Meat Less: The Next Food Revolution (Copernicus Books) [1st ed. 2023] 9783031239632, 3031239636

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THE NEXT FOOD REVOLUTION

DAVID JULIAN MCCLEMENTS

Copernicus Books Sparking Curiosity and Explaining the World

Drawing inspiration from their Renaissance namesake, Copernicus books revolve around scientific curiosity and discovery. Authored by experts from around the world, our books strive to break down barriers and make scientific knowledge more accessible to the public, tackling modern concepts and technologies in a nontechnical and engaging way. Copernicus books are always written with the lay reader in mind, offering introductory forays into different fields to show how the world of science is transforming our daily lives. From astronomy to medicine, business to biology, you will find herein an enriching collection of literature that answers your questions and inspires you to ask even more.

David Julian McClements

Meat Less: The Next Food Revolution

David Julian McClements Department of Food Science University of Massachusetts Amherst AMHERST, MA, USA

ISSN 2731-8982     ISSN 2731-8990 (electronic) Copernicus Books ISBN 978-3-031-23963-2    ISBN 978-3-031-23961-8 (eBook) https://doi.org/10.1007/978-3-031-23961-8 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

Dedicated to Isobelle, Jayne, and the rest of my family

Preface

The strong reliance of the modern diet on meat as a major source of protein and other nutrients is leading to ethical, environmental, and health concerns. The raising of livestock for food is linked to greenhouse gas emissions, pollution, water depletion, and biodiversity loss. Billions of animals are confined and slaughtered for food each year, often under highly stressful conditions on factory farms. The production of livestock animals increases the risk of antibiotic resistance and zoonotic diseases (like coronavirus), which is a major safety concern. The consumption of red meat and processed meat has been linked to health concerns. However, replacing meat with alternative protein sources may have unforeseen nutritional consequences. This book critically explores the environmental, ethical, health, and safety reasons for reducing the amount of meat in our diet. It also highlights the scientific and technological advances that are creating protein-rich alternatives to meat, such as plant-, microbial-, and insect-based meat analogs, as well as laboratory grown (“cultured”) meat. The potential of each of these technologies to create a more sustainable and healthy diet is assessed. Amherst, MA, USA

David Julian McClements

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Acknowledgements

There are many people I must thank for their contributions to this book. First, I must thank my wife Jayne and daughter Izzy who encouraged and supported me throughout the writing process. I must also thank my family in England and Scotland who provided thoughtful comments and suggestions on several of the chapters, including my brother Guy, my nephew Jake, and my niece Chelsea, as well as my Mam and Dad. I thank Matthew Moore and Hualu Zhou, from my department at the University of Massachusetts, for providing valuable comments and suggestions on some of the chapters. I thank Steven Finn, the production manager at the Billingham site of Quorn, for taking time out of his busy schedule to show me around the production facilities there. Steven was a fantastic host who revealed how an idea I had only read about in academic articles (producing proteins from microbes) could be implemented in the real world. I thank Christian Bärtsch from Essento in Switzerland for his valuable input into the chapter on insect foods, as well as providing photographs of the delicious bug burgers his company makes. I am grateful to Amadeus Driando Ahnan-Winarno for many fruitful discussions about tempeh and tofu. I also thank all the food companies who provided photographs for this book, including Impossible Foods, Beyond Meat, Upside Foods, Revo Foods, Rival Foods, Better Nature, Air Protein, Quorn, and several others. I am extremely lucky to work in an intellectually stimulating and collegial environment at the University of Massachusetts, which is a tribute to all the undergraduates, graduate students, Post Docs, visiting scientists, staff, and faculty in our department. Special thanks go to my drinking buddies, Profs. Lutz Grossmann, Matthew Moore, and David Sela, for all their sage advice over fermented beverages in our local pubs. Finally, I would like to thank ix

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everybody at Springer, especially Daniel Falatko, for believing in this project and helping to bring it to fruition.

Contents

1 Should  I Eat Meat?  1 A Meat-Stuffed Past   1 2 Meat  and the Environment: How Livestock Are Taking a Big Bite Out of Our Planet  5 The Need to Feed    6 People Love Meat (Especially Americans)    7 Animals are Not Efficient Food Sources    8 Don’t Feed the Animals (or You’ll Damage the Environment)    9 All Farms Are Not the Same   12 It’s Important to Set Clear Boundaries   15 Support Diversity  17 My Takeaway  18 References  20 3 An  Ethical Dilemma: To Meat or Not to Meat? 23 Doing the Right Thing Is Hard   24 What Is Ethics?   25 Situational Ethics  30 Where Do We Get Our Moral Compass?   31 The Size and Shape of the Problem   32 All Lives Are Not the Same   34 Meat Eating: All or Nothing?   36 Regulating Life and Death: Do Animal Welfare Regulations Solve the Problem?  37 xi

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Cowmageddon – What Would Happen to Livestock Animals If We Stopped Eating Meat?   39 My Takeaway  40 References  41 4 M  eat and Nutrition 43 Is Eating Less Meat Healthier?   44 What Is Health?   44 How Does Food Affect Our Health?   45 Fantastic Voyage: From Our Foods to Our Bodies   45 Gut Evolution: Are We Designed to Eat Meat?   48 The Agricultural Revolution: Going Backwards   52 Can We Get All the Nutrients We Need from a Meat-Free Diet?   53 Macronutrients  58 Proteins  58 Fats  63 Carbohydrates  67 Micronutrients  68 Iron  70 Zinc  71 Calcium  71 Vitamin B12  72 Vitamin D  72 Omega-3s  73 Nutraceuticals  75 Digestibility and Bioavailability   76 Are Vegetarians and Vegans Healthier than Meat Eaters?   79 All Plant-Based Diets Are Not the Same   80 My Takeaway  81 References  82 5 Staying  Alive: Is a Meat-Free Diet Safer? 85 Keeping Our Foods Safe   86 The Good Old Days   87 Food Regulations  88 Which Is Safer: Animal- or Plant-Based Foods?   90 The Severity of Illness   92 Drugs and Chemicals   95 The Rise of Superbugs: Antimicrobial Resistance   96

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The Shock of the New: Allergies   99 Not to Be Taken Lightly: Heavy Metals  100 A Growing Problem: Microplastics  102 Home Chemistry: Toxins Produced During Cooking  104 Global Pandemics  106 My Takeaway  108 References 109 6 Plant-Based  Meat: Building Meat from Plants113 Turning Plants into Meat  114 The Structural Architecture of Meat  115 Plant-Derived Ingredients  118 Proteins 119 Carbohydrates 120 Fats 122 Special Effects: Colors and Flavors  124 The Food Artists Palette: Plant-Based Ingredients  126 Food Architecture: Assembling Plant-Based Meats  129 Designing and Building Meat Analogs  129 Machining Meat Analogs  130 Molecular Design of Meat Analogs  135 Data-Driven Design  136 Are Plant-Based Foods Better for Our Planet?  137 Is Plant-Based Meat Healthier?  139 Is Plant-Based Meat Safer to Eat?  141 Is Plant-Based Meat More Ethical?  142 But Can Eating Plant-Based Meat Really Make a Difference?  143 My Takeaway  144 References 145 7 Biotech  Meat: Growing Meat from Cells149 Should We Believe the Hype?  150 The Biotech Revolution  150 Cultured Animal Cells: Clean Meat  151 How Is Cultured Meat Made?  151 A Brief History of Cultured Meat  154 Better than Real Meat?  157 Making Cultured Meat a Reality  158 Cultured Bug Meat  160

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Celebrity Meat and Cannibal Burgers  161 Cultured Microbial Cells: Microbial Meat  162 A Fortuitous Tour  162 Producing Microbial Meat  163 Better than Real Meat?  168 A Diverse World  169 Food from Air  170 Precision Fermentation: Milking Microbes  174 What Is Precision Fermentation?  175 I Love GMO  176 Fermenting Our Future Foods  178 My Takeaway  181 References 182 8 Bug  Meat: Assembling Meat from Insects185 What’s for Dinner? Bug Meat!  186 Eating Bugs Is Normal  186 Cooking with Bugs  188 The Science of Bug Meat  192 But Would You Eat It? The Yuck Factor  194 The Power of Expectation  194 Bug Burger Taste Tests  195 Why Don’t We Like Eating Bugs?  197 Changing Minds, Changing Palates  198 We Shall Overcome  199 We Are All Entomophagists Anyway  200 Bug Farming: Mini-livestock  200 Is Eating Bugs Good for the Environment?  202 Is Bug-Based Meat Healthier for Us?  203 Are Bugs Safe to Eat?  204 Factory Pharms: Using Bug Bits as Pharmaceuticals and Nutraceuticals 206 Is it More Ethical to Eat Bugs?  206 My Takeaway  209 References 210 9 The  Past Is the Future: Tofu and Tempeh Rejuvenated213 Inspirations from Our Edible History  213 A Missed Opportunity in China  215

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History of Meat Alternatives  216 Tofu 220 History of Tofu  220 Tofu Production  223 Future Tofu  224 Tempeh 226 History of Tempeh  228 Tempeh Production  230 Future Tempeh  233 Tofu and Tempeh: What Are the Benefits?  235 My Takeaway  237 References 237 10 Future  Foods: Diet 2050239 Should I Eat Meat?  239 Diet 2050  242 References 243 I ndex249

About the Author

David Julian McClements  was born in the north of England but has lived in California, Ireland, France, and Massachusetts since then. He is currently a Distinguished Professor at the Department of Food Science at the University of Massachusetts where he specializes in the areas of food design and nanotechnology. He has written numerous books, published over 1300 scientific articles, been granted several patents, and presented his work at invited talks around the world. He is currently the most highly cited author in the food and agricultural sciences. He has received awards from numerous scientific organizations in recognition of his achievements and is a fellow of the Royal Society of Chemistry, American Chemical Society, and Institute of Food Technologists. His research has been funded by the United States Department of Agriculture, National Science Foundation, NASA, and the food industry.

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1 Should I Eat Meat?

Abstract  In the past, the author was an avid meat eater. Several years ago, he became a vegetarian because his daughter stopped eating meat and he wanted to support her. After she left home, he had to decide whether to remain a vegetarian or to start eating meat again. This question stimulated him to investigate the arguments for and against eating meat. This book outlines the environmental, ethical, health, and safety arguments for reducing the amount of meat in our diet. It then highlights the new technologies being developed to create delicious, affordable, healthy, and sustainable alternatives to meat, including insect-, microbial-, and plant-based meat analogs, as well as lab-­ grown meat. The principles behind each of these disruptive technologies are discussed, as well as their potential to replace meat as a source of proteins in the diet. Keywords  Vegan • Vegetarian • Ethical • Environmental • Health • Meat • Plant-based meat Nothing will benefit human health and increase the chances for survival of life on Earth as much as the evolution to a vegetarian diet. Albert Einstein

A Meat-Stuffed Past I was brought up in Northern England on a diet where meat was the centerpiece of almost every meal. Meat pies, bangers (sausages), and corned beef sandwiches were some of my favorites. But the king of meals was roast beef © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 D. J. McClements, Meat Less: The Next Food Revolution, Copernicus Books, https://doi.org/10.1007/978-3-031-23961-8_1

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and Yorkshire pudding, which we typically had for Sunday dinner. I can still remember the house filling up with the wonderful aroma of roasting meat in my mother’s kitchen on Sunday mornings. This smell still takes me back to fond memories of my family sitting around the dining room table eating together. It never occurred to me then that meat would not always be such an integral part of my life. I first became a vegetarian over three decades ago after taking a meat science class in my undergraduate degree. The guest speaker worked in the livestock industry and had come to our class to tell us how they turned animals into meat. He started his lecture with a photograph of an anxious-looking cow being transported to an abattoir and then methodically explained all the steps needed to convert this beautiful animal into a pile of minced and sliced flesh. The gruesome images of the various steps involved had a visceral impact on me. They brought home the link between a living creature and the food on my plate. I immediately became a vegetarian. My newfound ethical sensibility did not last very long though. After only a few months, I was eating bacon sandwiches, pork pies, and roast beef again, which was mainly because the vegetarian food available at the time was so bad, and I did not have the time, energy, or skills to prepare tasty meat-free dishes for myself. I only became a vegetarian again a few years ago. My daughter Isobelle, who was 13 at the time, came home from middle school one day and declared she had become a vegan and was never going to eat meat again. In her environmental science class, they were reading a book about the meat industry. As my wife and I sat at the dinner table enjoying our sautéed chicken breast, she lectured us about all the things wrong with eating meat. For many years, my wife and I had considered going vegetarian, but we were so set in our culinary habits that it was hard to change. Now we were confronted by our passionate teenage daughter who was making a stand on something she really believed in. It was time for us to get out of our comfort zone and give vegetarianism another go. An added benefit was that we wouldn’t have to prepare two versions of every meal. A few years later, my daughter left home for college and so there was no need to prepare any additional meat-free meals or to justify eating meat to a passionate teenager. We could finally eat meat again! But we didn’t. Rather than stopping off at the first hamburger joint we passed after dropping her off at college, I decided to investigate the reasons for remaining a vegetarian. In this book, I explore the pros and cons of being a vegetarian or vegan by critically examining the environmental, ethical, nutritional, and safety impacts of not eating meat. I also show how modern science is developing a range of innovative technologies that are making it easier for us all to eat less meat.

1  Should I Eat Meat? 

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Before we start, I should state that there are no easy answers, and it is up to each person to make their own decisions on whether they decide to eat meat or not. My intention is to provide the knowledge that might help people make an informed choice about this important issue. I also want to introduce some of the passionate scientists and entrepreneurs who are making it their life’s mission to create a more healthy, sustainable, safe, and ethical food supply. Many of these people are still relatively young and so have the most to gain by creating a food system that protects our planet for themselves and for future generations.

2 Meat and the Environment: How Livestock Are Taking a Big Bite Out of Our Planet

Abstract  One of the most compelling reasons for not eating meat is to reduce the negative impacts of livestock production and processing on the environment. The raising of livestock animals for food leads to appreciable greenhouse gas emissions, pollution, water resource depletion, deforestation, and biodiversity loss. The global population is growing, and people are becoming wealthier, which means more food needs to be produced in the future. This is putting an increasing strain on our natural resources. Life cycle analyses have shown that the production of plant-based meat analogs, as well as meat analogs created from other sources of alternative proteins, is more sustainable than meat production. Consequently, there would be large environmental benefits if more people reduced the amount of meat in their diet. However, the alternative protein industry is only in its infancy and so it will be important to focus on finding effective strategies to reduce the environmental impact of the livestock industry in the near future. Keywords  Greenhouse gas emissions • Biodiversity loss • Pollution • Water resources • Deforestation By eating meat we share the responsibility of climate change, the destruction of our forests, and the poisoning of our air and water. The simple act of becoming a vegetarian will make a difference in the health of our planet. Thích Nhất Hạnh

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 D. J. McClements, Meat Less: The Next Food Revolution, Copernicus Books, https://doi.org/10.1007/978-3-031-23961-8_2

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The Need to Feed Listening to the news, it is hard not to be alarmed about the future of our planet. The temperature is rising. The polar ice caps are melting. Devasting floods and droughts are happening more frequently. Our rivers and oceans are being polluted and depleted. Deforestation is occurring at an alarming rate, causing a steep decline in animal, bird, and insect populations. The soil we need to grow our crops is rapidly losing its vitality. These widespread global disruptions are leading to serious concerns about whether we will be able to produce enough food for future generations without irreversibly damaging our planet. One of the major contributors to this impending global catastrophe is the way we currently produce our foods, especially our overreliance on meat. The rearing of cows, pigs, sheep, and chickens for food is depleting our planet’s resources and polluting our land, water, and air. Left unchecked, this problem is only going to get worse. The global population is continuing to rise and is expected to reach nearly 10 billion by 2050, meaning we will have to produce enough food by then to feed another 3 billion mouths (Fig. 2.1). Moreover, people in many parts of the world are becoming wealthier and their lifespans are increasing – which is certainly a wonderful thing. But there are 10

Global Population (Billions)

9 8 7 6 5 4 3 2 1 0 1900 1925 1950 1975 2000 2025 2050

Year

Fig. 2.1  The global population is predicted to rise to around 10 billion by 2050, meaning we have to produce much more food to feed all the extra mouths. (www.ourworldindata.org)

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consequences. As people become more affluent, they typically include more meat in their diet. In the past two decades, there has been an 80% increase in the number of animals eaten globally. If current trends continue, there may be another 50% increase in the amount of meat consumed by 2050. If left unchecked, the adverse effects of meat on our environment will only get worse. In this chapter, I explore the environmental impacts of consuming meat.

People Love Meat (Especially Americans) A wonderful resource for anyone looking for information about all sorts of things is Our World in Data (ourworldindata.org), which is run by Drs. Hannah Ritchie and Max Roser from the University of Oxford in the United Kingdom. They have compiled data on global meat production over the past few decades (Fig. 2.2), which shows there has been a rapid rise during this period. The world eats almost four times as much meat now as it did 50 years ago, with around 340 million metric tons being produced in 2018 (the latest year we have data for). This mountain of flesh is made up of over 70 billion

Meat Prodution (Million tonnes)

400 350 300 250 200 150 100 50 0

1960

1970

1980

1990

Year

2000

2010

2020

Fig. 2.2  The amount of meat produced each year is rising as the global population increases and people become wealthier. (www.ourworldindata.org)

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animals, with the vast majority of unfortunate creatures being chickens (69 billion). Even so, there are still around 1.5 billion pigs, 574 million sheep, and 302 million cows slaughtered every year. These numbers are truly staggering – for every person on the planet, almost 10 animals must die a year to feed them meat. Of course, this depends on the economic resources and cultural habits of the people in different parts of the world. On average, Americans eat much more meat than people in most other regions of the world (even beef-­ loving Argentina!). In 2017, the average American ate over 124 kg (273 lb.) of meat a year, which is equivalent to about a quarter of a cow, 1 pig, or 37 chickens.

Animals are Not Efficient Food Sources To raise, feed, house, slaughter, and transport this huge number of animals requires vast amounts of energy and has a major impact on our environment. This is because animals are not a particularly efficient means of converting the planet’s resources into food. The energy conversion efficiency of different livestock animals is shown in Fig. 2.3. This is related to the amount of dry feed that must be given to the animals to produce a given amount of meat. On average, the energy conversion efficiency for beef is less than 2%, which means

Beef

1.9

Lamb

4.4

Pork

8.6

Poultry

13

0

5

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Energy Conversion Efficiecy (%)

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Fig. 2.3  Energy conversion efficiency of different livestock animals. This is related to the amount of dry feed required to produce a given amount of meat. (www.ourworldindata.org)

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that over 98% of the energy used to produce it is wasted.1 For other types of meat, the conversion efficiency is better, but even for poultry it is still only around 13%. It would be much more efficient for us to simply eat plant-based foods directly, rather than using them to feed animals that we then eat. This low conversion efficiency is because the animal needs to use some of its food to grow and maintain organs that are not used as meat (hooves, cartilage, and bones). Moreover, it uses some of the energy stored in the food to power the biological processes needed to stay alive, such as breathing, thinking, moving, and maintaining its body temperature. If we just looked at these feed conversion efficiencies, we would think that it is never a good idea to consume meat. But we are not really comparing apples with apples. In many cases, animals are converting something we cannot eat (grass and hay) into something we can (meat). For food security reasons, there are therefore some strong arguments for raising livestock on land that humans cannot easily cultivate for plant-based foods. In the northeast of England, where I grew up, there are many rugged valleys and hills where it is impractical to grow agricultural crops (such as soybeans, corn, or wheat) suitable for human consumption, so farmers have traditionally raised sheep and cows there. Indeed, some of the most beautiful landscapes in England are the bleak moorlands and craggy hills and valleys found in the Yorkshire Dales and North Yorkshire Moors. These barren landscapes are divided by ancient stone walls that were used to keep the animals in place, which provides an enigmatic beauty and sense of history. More importantly, in many developing countries, the land and climate are unsuitable for raising agricultural crops but are suitable for raising animals that can eat grasses and other vegetation that is inedible to people. Consequently, meat is a critical source of nutrients and calories in the diet, which can help stave off hunger and malnutrition.

 on’t Feed the Animals (or You’ll Damage D the Environment) Despite these caveats, over three-quarters of the agricultural land available is currently used to produce crops to feed animals, rather than to feed us, even though the animal-based foods produced contribute less than a fifth of our calories (Fig.  2.4). The fact that livestock, particularly cows, are not very efficient at converting feed into food means that much more land and water  It should be noted that these are global averages. In reality, there are large differences in the energy conversion efficiencies of livestock animals depending on how they are raised. 1

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Agricultural Land

Calories

77% Livestock

17%

Livestock

23% Crops

83%

Crops

Fig. 2.4  Over three-quarters of the available agricultural land in the world is currently used to graze or feed livestock animals, but they produce less than a fifth of our calories. (www.ourworldindata.org)

is needed to produce the same amount of food, as well as much more fertilizers and pesticides. Moreover, there is much more pollution and greenhouse gases associated with livestock production. Again, it is useful to look at the data to get an idea of the magnitude of the impact of meat eating on our environment. There have been some very comprehensive studies on this subject that we can draw on. Joseph Poore from the University of Oxford led a study that compared the environmental impacts of around 38,000 farms producing over 40 different commonly consumed agricultural products around the globe [1]. The environmental impacts of producing different kinds of animal- and plant-based foods were compared, which involved a detailed analysis of all the inputs required to produce them, including water, land, fertilizers, pesticides, petroleum, electricity, farm machinery, trucks, ships, etc., as well as all the outputs associated with their production like methane and carbon dioxide emissions and the release of pollutants into the environment. The impacts of different protein-rich foods, including a traditional plant-based one (tofu) and several animal-based ones (beef, lamb, pork, and poultry), on environmental factors, such as land use, water used, greenhouse gas emissions, and pollution, are compared in Fig. 2.5. This data clearly shows that the production of plant-based proteins is much less damaging to our environment than that of animal-based ones, requiring less land and water to produce and causing much less pollution and greenhouse gas emissions. Indeed, the Economist magazine reported that the production of beef generates around 31 times more greenhouse gasses per calorie than tofu. Based on his findings, Poore concluded that a vegan diet is probably the single biggest way we can reduce our impact on planet Earth. In reality, while adopting a vegan diet is important, there are many other things we can also do to reduce our environmental

2  Meat and the Environment: How Livestock Are Taking a Big Bite… 

Water Use 1200

200 180 160 140 120 100 80 60 40 20 0

Water Use (L/NU)

Land Use (m2/NU)

Land Use 1000 800 600 400 200 0 Tofu

Beef Lamb Pork Poultry

Tofu Beef Lamb Pork Poultry

Protein Source

Protein Source

Greenhouse Gasses

Pollution 180 160 140 120 100 80 60 40 20 0

45 40 35 30 25 20 15 10 5 0

Acidification (lgSO2/NU)

GHG (lgCO2/NU)

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Tofu

Beef Lamb Pork Poultry

Protein Source

Tofu

Beef Lamb Pork Poultry

Protein Source

Fig. 2.5  Comparison of the environmental impacts of different protein sources. Livestock production is much worse for the environment than plant-based foods. (Figures replotted from original data in Poore and Nemecek [1])

impact, including driving, flying, and buying less, as well as reducing our food waste and energy use. The large land use of cows and sheep is because they usually have much more space to roam around than chickens and pigs. The relative freedom that these animals experience (provided they are not raised in factory farms) can be seen when one hikes across the hills and valleys of the Yorkshire Dales. There are cows and sheep dotted along the hillsides munching the lush green grass that comes from living in a rainy climate. In contrast, pigs and hens often have much less space because they are crammed into pens, coops, or sheds. The soybeans used to make tofu don’t mind being tightly packed together. The high level of greenhouse gasses produced by cows is partly because of the

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energy required to raise, transport, and process them, but mainly because of their methane-rich gaseous emissions (farts and burps). There has been some criticism of these kinds of studies by the livestock industry who believe they do not accurately reflect the real environmental impacts of livestock production. For instance, Farmers Against Misinformation argue that much of the water used for livestock production (at least for pastured animals) is green water that comes from rain, rather than freshwater sources. However, all our freshwater ultimately comes from rain and could be used to grow agricultural crops, rather than for raising animals. The same organization also argues that the overall contribution of greenhouse gas emissions attributed to livestock animals is grossly overstated. They argue that carbon dioxide in the air is converted into nutrients (sugars) by plants through photosynthesis. These plants are then eaten by livestock animals, which releases the carbon dioxide back into the air. Thus, when you consider the whole life cycle of carbon in the atmosphere, the net effects are small. This would seem to be an argument for keeping the food production system the way it is now. However, we urgently need to reduce the amount of greenhouse gasses in our atmosphere. If the livestock animals did not eat the plants, then some of the carbon in them would pass through their roots into the soil where it would be stored. We would then have a lot less greenhouse gasses released into our atmosphere, which would help in combating global warming. Obviously, farmers and others involved in the production of meat are concerned that their livelihoods would be negatively impacted if we all started eating less meat. It is therefore important to listen to these concerns and ensure that any transition to a meat-less diet is based on the best evidence available and considers the impact on all those involved. Ideally, some of the farmers who currently produce meat could produce ingredients for plant-­ based foods. But the total number of farmers needed in the future could be reduced because we would not need to produce as much food as we do now (because most of it is currently fed to animals).

All Farms Are Not the Same The environmental impact of raising animals for food depends on the manner in which it is done. There are huge variations depending on the type of animals and farming practices used [1]. The domesticated animals now used for livestock have been bred over centuries to be efficient at producing as much meat as possible, in as short a time as possible. Moreover, modern industrial farms often involve concentrated animal feeding operations (CAFOs), where

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huge numbers of animals are confined into a relatively small space and their feed is carefully designed to ensure maximum growth rates. This means that the animals raised for meat on large industrial farms often have less environmental impact (on some important measures) than those free to roam across green pasture lands. This was highlighted by the authors of a scientific study on the environmental impacts of different farming practices [2], who concluded “modern, intensive livestock systems, especially for beef, offer substantially lower land requirements and greenhouse gas emissions per kilogram of meat than traditional, extensive ones.” There is a wide variation in the environmental impacts associated with raising cows on different farms, but overall raising them on open pastureland requires much more land and generates much more greenhouse gasses (Fig. 2.6). I must admit, this really surprised me – I had always assumed that factory farming would be much worse for the environment. These authors went so far as to argue that modern factory farming practices could help protect the environment, especially in places like the Brazilian Amazon, since less land and resources would be needed to raise the cows. This is because the animals grow much faster and reach their full size in a shorter time. As a result, there would be less pressure to cut down the rainforests, which are essential for maintaining a healthy global climate. Before herding together all the cows happily roaming around our pasture lands and forcing them to live in the squalid conditions of a factory farm, it should be noted that there are serious ethical and environmental problems with these farms. The animals in CAFOs lead short and miserable lives, and they generate millions of tons of manure, which pollutes the surrounding land, air, and water. Indeed, the stinking sewage lakes associated with CAFOs Greenhouse Gas Emissions

Land Use

Pastoral

Pastoral

Factory

Factory

0

20

40

60

80

100

120

Greenhouse Gasses (kg CO2-eq)

140

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Land Use (m2)

Fig. 2.6  Comparison of some environmental impacts of raising cows on pastureland or in factory farms. Raising them in factory farms requires less land and produces less greenhouse gasses. (Figures replotted using data from Swain et al. [2])

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may greatly reduce the quality of life and health of the people living near them. Moreover, forcing animals to live under cramped conditions increases the risk of disease, both to the animals and to us, which will be discussed in a later chapter. As in much of life, there is often no perfect solution, and we must come to some compromise based on what we value most. If people consumed less meat as part of their diet, then there would be fewer concerns about producing livestock using traditional pastoral methods, which are less environmentally friendly. As a result, a greater fraction of livestock animals could be raised under conditions where they led happier lives, without causing excessive pollution. In addition, newer “regenerative farming” practices can reduce greenhouse gas emissions, improve soil quality, and reduce pollution [3]. However, these methods may not be suitable for the industrial-scale production of meat. Moreover, the meat produced is often much more expensive and so may not be affordable for many people. Researchers are trying to develop innovative methods to reduce the negative impacts of livestock on the environment. A major contribution of cows to global warming is their tendency to produce methane in their stomachs when they digest grasses and other feed, which is then released into the atmosphere through their mouth (burps) or rear end (farts). Scientists in Australia are working to reduce these methane emissions from cows, thereby decreasing their negative impact on global warming [4]. These scientists found that adding even small quantities of a crimson seaweed grown off the coast of Australia to the cow’s diet could reduce methane production by a staggering 98%. This seaweed contains a natural substance (bromoform) that blocks the conversion of hydrogen and carbon to methane inside the cow’s stomach. Moreover, growing seaweed actually extracts greenhouse gasses from the atmosphere, thereby having a beneficial effect on our climate. Several entrepreneurial companies around the world have already established seaweed farms and processing facilities to extract this methane-reducing compound, so they can provide ingredients that farmers can incorporate into their animal feed. If these ingredients can be produced economically in sufficient quantities, they could have a huge impact on global warming. Of course, it is also important that they don’t harm the cows and that the cows want to eat them. An innovative policy approach recently proposed by the New Zealand government to tackle this problem was to tax cow burps. Cow burps make such a large contribution to greenhouse gas emissions, any approach that can limit them is welcome.

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It’s Important to Set Clear Boundaries Another comprehensive study of the impact of different foods on the health of our planet and ourselves was led by Professor Walter Willett, a renowned nutrition scientist from Harvard University. The results of this study, which included 37 renowned scientists from different disciplines, were published in the prestigious medical journal Lancet [5]. This paper has already been cited thousands of times by other scientists and has attracted substantial media attention. The authors recommended that one of the most effective ways of creating a healthier and more sustainable food production system is to reduce the amounts of animal foods we consume, especially red and processed meat [5]. Professor Willett and his colleagues state: Transformation to healthy diets by 2050 will require substantial dietary shifts. Global consumption of fruits, vegetables, nuts and legumes will have to double, and consumption of foods such as red meat and sugar will have to be reduced by more than 50%. A diet rich in plant-based foods and with fewer animal source foods confers both improved health and environmental benefits.

The authors of this study don’t mince their words: “Global food production threatens climate stability and ecosystem resilience and constitutes the single largest driver of environmental degradation and transgression of planetary boundaries.” In other words, we’re all screwed if we don’t do something soon to change our eating habits. Indeed, they state that we need a “radical transformation” of the global food system if we are going to have any hope at all. Luckily, the scientists have some concrete suggestions about how we can go about doing this. Indeed, they go so far as to set “universal scientific targets for the food system that apply to all people and the planet.” Despite being a highly ambitious goal, I think this kind of kick up the bum is what we need at this critical time. Prof. Willett and his colleagues came up with a concrete set of guidelines to define how a healthy food supply can be produced without transgressing planetary boundaries and damaging the planet. Some of these boundaries are shown in Table 2.1. This framework can be used by individuals, governments, and industries to work towards a more environmentally sustainable food supply, so that we can feed future generations without damaging the planet. Unfortunately, we are already approaching or exceeding many of the proposed boundaries and this is only likely to get worse unless we do something about it soon (Fig. 2.7).

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Table 2.1  Targets for key food and agriculture processes that need to be reached to produce a healthy global diet without damaging our planet – proposed by the EAT-­ Lancet Commission [5] Earth system process

Control variable

Target boundary

Climate change Land-system change Freshwater use Nitrogen cycling Phosphorus cycling Biodiversity rate

GHG emissions Cropland use Water use Nitrogen application Phosphorus application Extinction rate

5 gigatonnes CO2-eq/year 13 million km2 2500 km3/year 90 teratonnes/year 8 teratonnes/year 10 species per year

Planetary Boundaries

400

5500

350 300 250 200 150

Target Planetary Boundary

100 50 ra te io n

Ex t

in ct

ic

at io n

n ho ro us

ap pl

pl ic

at io

ns ap

Ph os p

N it r og en

H

G

em is

si o

us an d G

C ro pl

W at

er

us e

e

0

Fig. 2.7  Comparison of the current situation with the target planetary boundaries (expressed as percentage of target) set by the EAT-Lancet Commission [5]. Unfortunately, we have already exceeded many of the boundaries, especially the rate of extinction

The team of scientists involved were certainly focused on solving this problem. They came up with a specific set of actions that could be adopted to meet the proposed targets, which will involve some radical changes in the way we produce and consume foods: • Dietary changes: We need to change the types and amounts of foods we eat. In particular, we should eat less meat and more plant-based foods like fruits, vegetables, whole grains, nuts, and seeds.

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• Increase yields and efficiency: We need to improve our agricultural, transportation, and food production systems so we can sustainably produce more of these healthy foods using fewer resources (land, water, fertilizers, pesticides, and fossil fuels). • Reduce waste: We need to reduce the amount of food currently wasted during production, storage, and consumption. Radical changes in our agricultural, transportation, and food manufacturing systems are urgently needed to achieve these goals, as well as in the way our foods are promoted and sold. This will require policy changes at both the national and international levels to promote affordable, accessible, and sustainable healthy foods, such as taxes, subsidies, regulations, grants, and education programs. These policy changes should be designed to encourage the agriculture and fishing industries to produce a diverse range of healthy and sustainable foods, rather than on just increasing quantities and lowering costs. A new agricultural and food revolution is also required that stimulates the development and adoption of technological and management innovations. Improved farming practices like regenerative agriculture will be critical, as well as advanced technologies such as gene editing, cellular agriculture, alternative proteins, biotechnology, nanotechnology, sensors, robotics, automation, and big data [6, 7]. The food and agricultural industries are ripe for transformation. Later in this book, I will explore some of the exciting research that is being carried out to create healthy and sustainable alternatives to meat.

Support Diversity Finally, the land we are using to raise cattle is displacing other animals leading to a dramatic decrease in global biodiversity [8]. To produce ever more food for humans, we are cutting down rainforests, savannas, and grasslands and converting them into crop and pasture lands, which is threatening many plant, animal, and insect species with extinction. The World Wildlife Fund estimates that over 69% of the mammals, birds, fish, and reptiles on the planet have been wiped out by humanity since 1970, with food production being a major contributor to this problem [9]. Indeed, the majority of mammals and birds on the planet are now those used to produce our food (Fig. 2.8). The devastating impacts of the modern food system on biodiversity have also been pointed out by the Royal Institute of International Affairs in London [10]. They found that the average rate that species are now going extinct is orders of magnitudes higher than at any time during the past 10 million years. In the

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Mammals

FARMED ANIMALS (60%)

Birds

WILD BIRDS (29%)

HUMANS (36%) FARMED BIRDS (71%)

WILD ANIMALS (4%)

Fig. 2.8  Distribution of global biomass across all mammals and birds [11]

relatively short time that modern human beings have been around we have caused irreparable damage to the other species that share our planet. The conversion of natural ecosystems (like the rainforests) into farmland for pasture or crop production was found to be the main driver for biodiversity loss, which was itself a result of our demand for ever cheaper and more abundant foods. Indeed, it is estimated that rainforests covering an area equivalent to that of California have been cut down during the past decade. The Royal Institute of International Affairs stresses the urgent need for societal, policy, and economic changes to create a more sustainable food supply, with special emphasis on switching from animal- to plant-based foods.

My Takeaway After exploring the scientific evidence about meat production and its impact on our environment, I am convinced that we will all have to eat less meat in the future. Otherwise, we will be unable to meet the food needs of future generations. Moreover, the environmental damage caused by relying on livestock to produce our food will make many parts of the planet unhabitable or at least hostile and unpleasant places to live. The alternative sources of proteins discussed in latter chapters, such as plant, microbial, bug, and cultured meat, require much less land and water than raising livestock, as well as causing less pollution, greenhouse gas emissions, and biodiversity loss. If we are serious about feeding the billions of new people that will be born over the next 30  years, we must make dramatic changes to the way we currently

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produce our foods. From an environmental viewpoint, this does not mean that all people have to completely stop eating meat – there are places in the world where it is not possible to grow sufficient agricultural crops. Livestock animals can convert grasses and other substances that are inedible to humans into nutritious foods, which is essential to the wellbeing and livelihoods of many people. In the past, livestock animals were an effective way of providing nutrients for relatively small communities. But with the rising global population and finite amount of air, land, water, and other resources available to us, we have to find alternatives to supplement or replace meat in the future. The land that is freed up from animal grazing or from producing feed for livestock animals could be allowed to return to the wild, which would help us to reduce greenhouse gas levels and biodiversity loss. Based on this evidence, I strongly believe that the environmental reasons for me not eating meat are extremely compelling. Having said this, the alternative protein technologies being developed to facilitate the transition to a meat-less diet are still in their infancy and currently make up only a tiny fraction of the market for real meat. It is therefore unlikely they will make an appreciable contribution to reducing meat consumption in the near future. For this reason, efforts to make the livestock industry less environmentally damaging should be a major priority for the near future. However, it is important that these efforts do not lead to even greater distress and suffering to livestock animals. Finally, I should stress that livestock production is only one factor contributing to global warming and other adverse environmental effects. The United Nations estimates that livestock production contributes around 14.5% of all total greenhouse gas emissions. Thus, while reducing the amount of meat we eat will improve our environment, we also need to reduce the negative impacts of the other major contributors to greenhouse emissions, like transportation, construction, and manufacturing. Ideally, we can all contribute to this goal by changing our own behavior. To gain some insight into my family’s environmental impact, I used the Cool Climate calculator from the University of California, Berkeley, to estimate our carbon footprint (coolclimate.org) (Fig. 2.9). Compared to other factors contributing to our carbon footprint, such as travel (mainly air and car), home (mainly energy, heating, construction, and water), goods (mainly furniture and clothing), and services, food only made up a relatively small contribution (8%). As a result, switching from an omnivore to a plant-based diet only leads to a modest reduction in greenhouse gas emissions of around 2.6%. This is significant, but it highlights the importance of looking at all aspects of our lives when trying to live more sustainably.

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Services

With Meat Without Meat

Goods

Food

Home

Travel 0

5 10 15 20 25 Carbon Footprint (tons CO2 eq/year)

Fig. 2.9  Calculation of the carbon footprint of my household (two adults with two cars in Western Massachusetts) using the cool climate carbon footprint calculator from the University of California, Berkeley (coolclimate.org). Food makes a small but significant contribution to our overall environmental impact

References 1. Poore, J. and T. Nemecek, Reducing food's environmental impacts through producers and consumers. Science, 2018. 360(6392): p. 987–+. 2. Swain, M., L. Blomqvist, J. McNamara, and W.J. Ripple, Reducing the environmental impact of global diets. Science of the Total Environment, 2018. 610: p. 1207–1209. 3. Kleppel, G.S., Do Differences in Livestock Management Practices Influence Environmental Impacts? Frontiers in Sustainable Food Systems, 2020. 4. 4. Schlossberg, T., An unusual snack for cows, a powerful fix for climate, in Washington Post. 2020, Washington Post: Washington, D.C. 5. Willett, W., J. Rockstrom, B. Loken, M. Springmann, T. Lang, S. Vermeulen, T. Garnett, D. Tilman, F. DeClerck, A. Wood, M. Jonell, M. Clark, L.J. Gordon, J.  Fanzo, C.  Hawkes, R.  Zurayk, J.A.  Rivera, W.  De Vries, L.M.  Sibanda, A. Afshin, A. Chaudhary, M. Herrero, R. Agustina, F. Branca, A. Lartey, S.G. Fan, B.  Crona, E.  Fox, V.  Bignet, M.  Troell, T.  Lindahl, S.  Singh, S.E.  Cornell, K.S. Reddy, S. Narain, S. Nishtar, and C.J.L. Murray, Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems. Lancet, 2019. 393(10170): p. 447–492. 6. WEF, Innovation with a Purpose: The role of technology innovation in accelerating food systems transformation. 2019, World Economic Forum: Geneva, Switzerland. p. 1–42.

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7. McClements, D.J., Future Foods: How Modern Science is Transforming the Way we Eat. 2019, New York, NY: Springer. 8. Diaz, S., J. Settele, E.S. Brondizio, H.T. Ngo, J. Agard, A. Arneth, P. Balvanera, K.A.  Brauman, S.H.M.  Butchart, K.M.A.  Chan, L.A.  Garibaldi, K.  Ichii, J.G. Liu, S.M. Subramanian, G.F. Midgley, P. Miloslavich, Z. Molnar, D. Obura, A. Pfaff, S. Polasky, A. Purvis, J. Razzaque, B. Reyers, R.R. Chowdhury, Y.J. Shin, I.  Visseren-Hamakers, K.J.  Willis, and C.N.  Zayas, Pervasive human-driven decline of life on Earth points to the need for transformative change. Science, 2019. 366(6471): p. 1327–+. 9. WWF, Living Planet Report 2022 – Building a nature- positive society. 2022, World Wildlife Fund: Gland, Switzerland. p. 1–115. 10. Benton, T., C.  Bieg, H.  Harwatt, R.  Pudasaini, and L.  Wellesley, Food system impacts on biodiversity loss: Three levers for food system transformation in support of nature. 2021, Chatham House: London, U.K. p. 1–75. 11. Bar-On, Y.M., R.  Phillips, and R.  Milo, The biomass distribution on Earth. Proceedings of the National Academy of Sciences, 2018. 115(25): p. 6506–6511.

3 An Ethical Dilemma: To Meat or Not to Meat?

Abstract  Many people do not want to eat meat for ethical reasons  – they believe it is wrong to confine and slaughter animals for food. There are billions of animals killed each year to feed us, with the vast majority being chickens. Livestock animals often live in uncomfortable and stressful conditions on factory farms and are then killed in traumatic ways in animal processing facilities, such as abattoirs. The people who work in these facilities are often traumatized by having to handle and slaughter large numbers of animals every day. There are therefore important ethical benefits from adopting a diet that reduces the number of animals killed for food. However, there are also ethical issues with plant-based diets, since some animals, birds, and insects are also killed during the growing and harvesting of agricultural crops. However, these numbers are much lower than the ones killed by the livestock industry. The major ethical theories applied to eating animals are discussed, including rights-based and utilitarian-based theories, as well as government regulations developed to improve animal welfare, which are often derived from these ethical theories. Keywords  Rights-based ethics • Utilitarianism • Regulations • Animal welfare • Vegetarianism • Veganism If it is in our power to prevent something bad from happening, without thereby sacrificing anything of comparable moral importance, we ought, morally, to do it. Peter Singer

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 D. J. McClements, Meat Less: The Next Food Revolution, Copernicus Books, https://doi.org/10.1007/978-3-031-23961-8_3

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Doing the Right Thing Is Hard One of the main reasons many people (including myself ) have given up eating meat is due to ethical considerations [1]. Indeed, a recent survey reported that animal welfare was the top concern of younger Americans [2]. They believe it is wrong to confine and kill animals for foods. For most of my life, I was comfortable with eating meat because I lived in a state of cognitive dissonance. I simply did not associate the delicious juicy slab of beef on my plate with the beautiful animals grazing on the green grass of North Yorkshire farms (Fig.  3.1). Moreover, my younger self was not motivated to find out more about the conditions that livestock animals lived under, or how they were reared and slaughtered for food. As I mentioned in an earlier chapter, I could no longer ignore this when I took a class on meat science as part of my undergraduate degree in Food Science at the University of Leeds. A guest speaker from the meat industry described how they would play music to pigs before they were slaughtered to relax them, because their flesh would be too tough if they were highly stressed before they were killed. (I hate to think what they would have done if their flesh was more tender when they were stressed.) The speaker also showed graphic pictures of how the animals were led from the trucks transporting them to the abattoir, slaughtered, and then hacked and sliced into different meat cuts. I was horrified by the images and stories I encountered in this lecture, which led me to (temporarily) become a vegetarian. But clearly, my ethical motivations were not strong enough then to stop me from eating meat for good. Other considerations overrode them, such as

Fig. 3.1  Cognitive dissonance stops us relating the beef on our plates to the animals they come from. (Images: cows on pastureland by Tim Green (left); roast beef on a plate by Jeremy Keith (right) (CC BY-SA 2.0 license))

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my unwillingness to invest the time, money, and energy into designing and cooking plant-based foods for every meal. In the mid-1980s, it was extremely difficult to buy high-quality plant-based meals in the supermarket or to find good vegetarian or vegan options in restaurants, and so it was necessary to get creative and make them yourself. I simply did not have the motivation, passion, or skills to do this. Now it is much easier to be a vegetarian or vegan in many countries with many supermarkets and restaurants offering a variety of tasty plant-based alternatives to meat. In the future, we may also have real meat products that have never been part of an animal, as well as other sources of protein-rich foods (like insects and microbes), which may help to alleviate many of these ethical concerns. These innovative approaches to creating a more ethical and sustainable food supply by replacing meat in our diet will be discussed later in this book.

What Is Ethics? When I started thinking about the ethics of eating meat, I realized I only had a vague idea about what ethics actually was. After dipping into a few philosophy books, I quickly realized it is an extremely complex discipline with a history stretching back through millennia to Socrates, Plato, Aristotle, and beyond. Philosophers have proposed numerous ethical theories, whose validity, merits, and limitations are still hotly debated. The Merriam-Webster dictionary defines ethics as “a set of moral principles” or “the principles of conduct governing an individual or a group,” whereas morals is defined as the “principles of right and wrong in behavior.” Thus, ethics is the branch of philosophy that deals with how individuals or groups choose to make decisions and take actions based on what they believe to be right or wrong. It is no surprise therefore that ethics is an extremely complicated and contentious subject, with many conflicting viewpoints. Human individuals are complex creatures living in dynamic and diverse societies that have different needs and wants that change over time. Different people and societies value things differently  – what may seem good to one person or group is not to another. Consequently, there is no single ethical system that fits everybody. These divisions are clearly apparent in many parts of the modern world. The polarization of ethical views is particularly extreme (and appears to be widening) in America, where I live, even though we all share the same country and government.

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Fig. 3.2  Thomas Jefferson was an American statesman and founding father who drafted the US Declaration of Independence, which is an example of a rights-based ethics. (Images from Wikimedia Commons)

In this chapter, I briefly outline the two major ethical approaches relevant to our discussion of the ethics of meat eating: rights-based and utilitarian-­ based ethics [3]. Rights-Based Ethics  In this approach, it is proposed that we all have certain rights just because we are human beings, such as the right to life, food, education, work, health, and liberty. The actions of an individual or a group can then be judged based on whether they are infringing on the rights of another person or group. For example, killing someone for no reason would be seen as a bad action. The United States Declaration of Independence is an early example of a document based on rights-based ethics. This document, which was drafted by Thomas Jefferson, enshrines the right to life, liberty, and the pursuit of happiness (Fig.  3.2). The United Nations Universal Declaration of Human Rights is a more comprehensive modern document that specifies the fundamental rights we should all have as humans. The eighteenth-century English philosopher John Locke was one of the first proponents of this ethical approach, and his theories were one of the main inspirations for the Declaration of Independence.

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Utilitarian-Based ethics  This approach to ethics is very different from the rights-based one. It decides whether an action is good or bad depending on whether it maximizes the overall “good outcomes” and minimizes the overall “bad outcomes” of the action. An ethical choice is therefore one that benefits the most people (or harms the fewest). For example, a right action could involve killing someone, if it resulted in other people’s lives being saved. The utilitarian approach is therefore incompatible with a rights-based approach, as utilitarian decisions could sacrifice the rights of the minority to protect the majority. The eighteenth- and nineteenth-century English philosophers Jeremy Bentham and John Stuart Mill played a seminal role in the elaboration of this approach to ethics and their theories are still hotly debated today (Fig. 3.3). The period of history when Bentham, Mill, and Locke lived was such a fertile time for the development of new ethical theories because of the major upheavals in politics, religion, and society that were occurring. Both the American and French Revolutions took place during this period. Ultimately, these thinkers were trying to understand how to create new relationships between people that would allow them to live better lives.

Fig. 3.3  Jeremy Bentham and John Stuart Mill were English philosophers who were some of the first proponents of utilitarianism. (Images from Wikimedia Commons)

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Several modern philosophers have applied these ethical theories to meat eating. Some of them have taken the rights-based approach, while others have taken the utilitarian-based one [4, 5]. In both cases, they have extended ethical principles originally designed to govern our behavior towards other people to include our behavior towards animals. Peter Singer, a Professor of Bioethics at Princeton University, wrote one of the seminal books on the ethics of meat eating in the mid-1970s, Animal Liberation. He takes a utilitarian-based approach to the welfare of animals, including livestock. He argues that these animals are sentient creatures with the capacity to experience joy, happiness, pain, and suffering. We should therefore consider these feelings when making decisions about how we interact with them. A “right” act would therefore be one that maximizes the happiness and joy of both the animals and humans involved (or at least minimizes their pain and suffering), whereas a “wrong” act would be the opposite. Consequently, the raising and slaughtering of animals for meat is usually considered to be wrong because it leads to an increase in the overall amount of pain and suffering in the world. However, utilitarianism does not necessarily mean that humans should not eat animals in all circumstances. If eating animals leads to an overall increase in the welfare of the humans and animals involved, then it may be deemed right to eat them. For instance, it may be morally acceptable to eat animals provided they led a relatively good life and were killed painlessly without experiencing stress, and the benefits to the people eating them outweighed the costs to the animals. In practice, it is hard to accurately weigh the overall benefits and costs associated with eating meat, since life is messy and can rarely be quantified using simple mathematical equations. Moreover, there may be some disconcerting consequences. Would it be justifiable to murder a cattle rancher if it saved 100 cattle from being slaughtered for meat? Other philosophers, like Tom Regan in his book The Case for Animal Rights, argue that animals have inherent rights, like the right not to be harmed or killed. However, there are a range of viewpoints on precisely what rights should be given to animals. Some people believe they should be given the same rights as humans and never be used as food. Others believe they should have a right not to be treated cruelly but otherwise can be used as food. It is extremely challenging to decide which animals to give rights to and what kinds of rights to give them. Where do we draw the line? Livestock animals appear to be creatures that deserve some rights, but what about shellfish, insects, and plants? At a conference organized by the US National Academies of Sciences, Garrett Broad and Robert Chiles proposed a conceptual map for understanding the different ethical attitudes to eating meat and meat alternatives

3  An Ethical Dilemma: To Meat or Not to Meat? 

EcoModernists

Meat Attachment

Techno-Optimism (Utilitarian)

Ethics of Meat Eating

Carnivore Traditionalists

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High-Tech Vegans

Meat Aversion

Plant-based Foodies Techno-Skepticism (Rights-based)

Fig. 3.4  The ethics of meat eating can be mapped out depending on a person’s attachment to meat and their techno-skepticism. Based on a scheme presented by Garrett Broad and Robert Chiles at the “Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health” meeting of the National Academies of Science (2022).

(Fig. 3.4). They categorized people’s ethical stances according to their views on meat eating and modern technology. Interestingly, they equated a person’s stance on modern tech to specific ethical views. Modernists tend to be more utilitarian, whereas traditionalists tend to be more rights-based. According to Broad and Chiles’ conceptual map, people with a strong attachment to meat eating, but who are wary of modern tech, are carnivore traditionalists who adamantly defend their right to enjoy platefuls of burgers and steaks. People who have favorable views on meat eating, but are more comfortable with modern tech, are willing to reduce the amount of meat they consume and try meat alternatives. These eco-modernists are more likely to become flexitarians. Those of us with a strong aversion to eating meat may be high-tech vegans or vegetarians willing to try the new generation of meat substitutes (like plant- or microbial-based meat analogs) or plant-based foodies who stick to a more traditional vegan diet consisting of fruits, vegetables, cereals, nuts, and legumes. Knowledge of the ethical beliefs of consumers is important to the government and the food industry because it influences how they promote and market meat alternatives. The American philosopher Carlo Alvaro has recently published several books on the ethics of veganism and vegetarianism [4, 5]. He points out that

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there is no consensus among philosophers on this subject, and that most regular people do not even know, understand, or care about the various theories put forward by philosophers. He states: “ethical theories are for philosophers not for people.” Alvaro argues for a more practical approach to the ethical treatment of animals based on virtue ethics. In this approach, a right action is one that a virtuous person would make in a given situation. A virtuous person would not confine and slaughter animals because they believe compassion, empathy, benevolence, and nonviolence are important. Personally, I don’t find this argument to be clear, convincing, or useful either, since it is hard to objectively define what virtues are. In many cases, violence may be undesirable, but in specific cases it may be desirable because it leads to less violence overall. For instance, shooting a gunman before he can kill a classroom of school children would be considered virtuous by most people. Even without knowing anything about the ethical theories that philosophers argue about, I think many of us would agree that livestock animals are sentient beings that can feel pain and experience suffering. If possible, we should therefore act in a way that reduces this pain and suffering. For instance, we could ensure that they do not live in undesirable conditions and should not be killed in a way that causes them fear and distress (if they are to be killed at all).

Situational Ethics Ethical beliefs are not universal or fixed. They change over time and are different in different places and situations. We cannot simply apply the ethical standards of a modern agricultural-industrial society to other existing and past societies. People who rely on meat to survive may have a different view of animal rights than those of us who can buy our food in supermarkets and restaurants. In some cases, the animals they eat may live freely before they are killed, which is in stark contrast to the livestock animals trapped in the industrial-­scale mass-killing systems used to produce meat in modern Western societies. We must therefore be careful not to impose our ethical beliefs on those living in different circumstances. Having said this, we may disagree with some of the practices carried out in other societies when they subject animals to unnecessary pain and suffering, and be warranted in encouraging people in these societies to change their practices. The vast majority of people in developed countries do not need to raise or kill animals for food – they simply go to a restaurant or supermarket to buy meat. Consequently, they do not have direct experience of raising and

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slaughtering animals and can easily dissociate the meat on their plate from the animal it came from. This makes us ignorant of the pain and suffering that livestock animals experience. Moreover, in many developed countries there are now good alternatives to meat that can help to alleviate this industrial-­ scale pain and suffering. We are therefore in a different ethical situation than many other people throughout history and in other parts of the world.

Where Do We Get Our Moral Compass? Most people in the United States and other developed countries eat meat, whereas a small but growing minority do not. It is interesting to consider the factors influencing people’s choices around meat eating, as this may impact the transition from a more to less meat-orientated diet. Before becoming a vegetarian, I did not spend a lot of time considering the ethical implications of eating meat. I simply chose foods that were familiar, tasty, affordable, and convenient, which usually meant meat. I did have periodic misgivings about eating animals, which were related to ethical, environmental, and health issues, but I never thought too deeply about them. I think many people are in a similar position. They have some concerns about meat eating but they have so many other things going on in their lives they do not have the time, energy, or inclination to change their diets. Moreover, they may simply not have the financial resources to purchase meat alternatives, which are often more expensive than real meat. Sometimes, our attitudes towards eating meat are strongly influenced by other beliefs. Religion is one of the most important belief systems influencing our decisions towards eating animals. Some religious doctrines provide the practitioners of their faiths with clear guidelines about what they can and cannot eat. There are, however, wide variations in the guidelines provided by different religions about whether meat can be eaten or not, and what types of meat can be consumed. Buddhists, Jains, Rastafarians, and Seventh-Day Adventists completely avoid meat. Jews and Muslims avoid pork, Hindus avoid beef, and Catholics avoid meat on Lent Fridays, Ash Wednesday, and Good Friday. Most Protestants appear to have no restrictions about eating meat, and so people are free to choose an omnivore, vegetarian, or vegan diet. For those of us who do not believe in a higher power, there are no external ethical rules that stipulate whether we should eat meat or not. We must make this decision based on our own values. However, we may also be influenced by other factors, such as peer pressure and marketing. If I lived in a small rural town in Texas surrounded by cattle ranchers, I might be much less likely to

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become vegan than if I lived in a Californian metropolis surrounded by hippies.

The Size and Shape of the Problem The number of animals killed to provide us with food is staggering. Over 70 billion animals are slaughtered every year to feed us, with chickens making up over 98% of this number (Fig. 3.5). This corresponds to more than two thousand animals being killed every second of every day. Many of these animals spend their entire lives under uncomfortable and highly stressful conditions, especially those raised in factory farms. Livestock animals may be prematurely taken away from their mothers, force fed, restricted to confined spaces, bred to have bodies designed for meat rather than for living comfortably, and handled and killed in brutal ways (Fig. 3.6) [6]. The fact they are packed so closely together promotes mental distress, fighting, and injury. The USDAs Poultry Industry Manual recommends that a fully grown chicken should have about 1 square foot of space, which is just bigger than its body size. Imagine spending NUMBER OF ANIMALS KILLED PER SECOND FOR FOOD

2200

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18

10

Fig. 3.5  Billions of livestock animals are killed each year to put food on our plates. This figure shows the number of animals killed per second for food

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Fig. 3.6  Chickens, pigs, and cattle in factory farms often have little room to move and live under unnatural conditions that are highly stressful. (Images: Creative Commons – see Figure Permissions)

most of your life in a box the size of a coffin. Farmers often cut off the horns of cattle, the tails of pigs, and the beaks of chickens to avoid these injuries, which is good for the farmer but not for the animals or birds. Livestock animals living under these stressful and unnatural conditions are more prone to disease and deformity, further reducing their quality of life. Clearly, there is a huge amount of distress and suffering associated with raising these animals for food, especially in factory farms. As discussed later, the public’s concern about animal welfare has led to major improvements in the ways animals are bred, housed, handled, and killed in some countries. In these places, government regulation of the meat industry has become stricter with the aim of improving animal welfare. However, the very nature of this industry means that animals will always suffer to some degree. Several individuals and organizations have played a pivotal role in highlighting the terrible plight of the animals living in factory farms, which have helped change people’s attitudes towards the treatment of livestock. The vivid descriptions of these animals’ lives in the books by Peter Singer (Animal Liberation), Jonathan Safran Foer (Eating Animals), and Ed Winters (This Is Vegan Propaganda) are heart wrenching and chilling. The nonprofit organization People for the Ethical Treatment of Animals (PETA) is an animal rights group that highlights the inhumane practices on factory farms and slaughterhouses and has advocated for veganism for several decades. This organization

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has been criticized for some of the tactics it has employed in its campaigns, but it has played a pivotal role in highlighting many of the injustices done to animals by people. I read Ed Winters book This Is Vegan Propaganda as I was writing this chapter and was horrified by the level of pain and suffering that animals in the meat, dairy, and egg industries endure to provide us with food. He describes the lives of animals on farms and slaughterhouses in the United Kingdom, which is considered to be one of the most humane countries in the world for its treatment of animals. Even here, livestock animals lead terrible lives, despite the fact the conditions on farms, feeding lots, and slaughterhouses have often been approved by the Royal Society for the Prevention of Cruelty to Animals (RSPCA) and have received the “Red Tractor” seal of approval. The RSPCA is an organization that prides itself for its kindness to animals and that states on its website that “animals have feelings too.” On its website, the Red Tractor organization states that “animal welfare is the number one priority for all Red Tractor livestock farmers. They work tirelessly to ensure the wellbeing of their animals.” If the animals whose welfare is protected by these organizations are mutilated (castrated, debeaked, detailed, dehorned, etc.), live in cramped and stressful conditions, and are slaughtered in terrifying ways, then what is happening to the animals that live in other parts of the world where their treatment is considered to be less humane?

All Lives Are Not the Same A livestock animal’s quality of life depends on where it is raised. A cow raised on a rural farm producing organic beef may spend much of its life on grass pastures where it is free to roam, before being fattened up and killed. In the United States, the Department of Agricultural (USDA) has created regulations that specify how livestock should be raised if the meat obtained from them is going to be labeled as “organic” (and therefore sold at a premium). The animals should have access to outdoor pastures throughout the year, fed organic feed, given access to clean water, and not treated with growth hormones or antibiotics. They should also be managed in a way that preserves natural resources and biodiversity. However, they can still be branded, dehorned, debeaked, and castrated if it is deemed necessary for their wellbeing and done in as humane a way as possible – although I cannot imagine a humane way of being castrated! Calves are often separated from their mothers early and cattle are often transported long distances to abattoirs to be

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slaughtered. Thus, these animals still suffer, albeit much less than those who spend most of their lives on factory farms. Only a relatively small fraction of livestock animals has the luxury of living their pre-slaughter days entirely on organic farms. The Sentience Institute estimates that the vast majority of these animals are currently raised in factory farms, including over 70% of cows, 98% of pigs, and 99% of chickens. These animals have a much more stressful and depressing life than their counterparts on organic farms. They spend most of their lives in cramped unnatural environments that cause high levels of stress and discomfort (Fig.  3.6). These facilities are designed to produce meat quickly, efficiently, and affordably, rather than ensure an animal’s welfare. Livestock animals are fed nutrient-­ dense foods, growth hormones, and antibiotics to ensure they grow quickly and stay healthy. Once they reach a sufficiently high weight, they are transported to the slaughterhouse. There are several promotional videos produced by the livestock industry, such as Farm to Fork: Life of a Beef Cow (YouTube). Typically, these videos show contented cows munching fresh grass in a lush green field on a rural farm rather than those cramped in a factory farm. They conveniently omit the stage where the cows enter the processing facility and come out the other end as steaks, bones, hooves, and heads (Fig. 3.7). This is not surprising considering the horrors occurring inside these facilities, even when they are operated according to regulations.

Fig. 3.7  The gruesome journey of a cow from the abattoir to the supermarket shelf. (Images: Creative Commons – see Figure Permissions)

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If one is going to eat meat, there is therefore a strong argument for only buying it from sources that use animals raised and killed in a more humane way. The Food Animal Concerns Trust (FACT), a nonprofit organization based in Chicago, advocates for humane farming practices. It argues that beef cattle should be provided access to open pastures rather than being confined to feedlots, they should be fed a diet that is natural to them, they should not be separated from their mothers too early, they should have access to outdoor pastures, and they should not be subjected to branding or removal of their tails or horns. Moreover, they should only be given antibiotics to treat specific diseases or illnesses, not as a prophylactic. Following these guidelines would greatly improve the quality of life of the cows and lead to healthier meat products. However, it may make meat more expensive and cause more damage to the environment  – because the animals need more land and water to raise them, as well as more food to feed them over their longer lifespans.

Meat Eating: All or Nothing? From an ethical perspective, we can reduce the level of animal suffering by reducing the amount of meat in our diets. But how far should we go? Is it necessary for us to completely stop eating meat (veganism or vegetarianism) or simply to reduce the level of meat we consume (flexitarian)? Personally, I believe that people should do whatever they can. Any reduction is progress. The more people who reduce the level of meat in their diet, the bigger will be the demand for meat alternatives, like plant-based meat analogs. This will lead to improvements in the quality, diversity, and affordability of meat substitutes. As a result, people may find it easier to move away from meat, leading to a self-reinforcing cycle towards a meat-less world. Are there situations where an ethical person can eat meat? Some philosophers argue that it is unethical to consume meat when meat substitutes are available that are not produced by causing pain and suffering to animals [7, 8]. Other philosophers argue that a virtuous person is justified in eating meat in some circumstances [9]. For example, the “virtuous new omnivores” do not support consumption of meat produced in factory farms, but they do believe that it is ethical to consume animals that have died from natural or other causes (like roadkill) or that are not supposed to feel pain and suffering (like insects). They argue that eating roadkill or bugs would reduce the demand for livestock animals, thereby reducing the overall level of animal suffering. It seems unlikely, however, that eating dead animals found on the side of the road would be sufficient to meet market demands or even be an acceptable

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source of meat for most people. In contrast, bugs could be a viable alternative to meat, which will be explored in Chap. 8. Recently, however, some studies have suggested that insects are sentient beings that can feel pain and suffering [10]. Given the huge number of insects that would be needed to feed the world (in the trillions), this finding could have major ethical implications. There are also ethical issues for those of us who do not eat meat. Even growing plants for foods causes harm to animals. The application of pesticides, the clearing of land for crops, and the harvesting of crops injure or kill numerous wild animals, birds, and insects. Nevertheless, the extent of this damage can be mitigated by modifying current agricultural practices. Moreover, most agricultural land is currently used to grow food for livestock animals. If we reduced the amount of meat we consumed, then we would also reduce the level of this collateral damage to wildlife.

 egulating Life and Death: Do Animal Welfare R Regulations Solve the Problem? It is important not to confuse animal welfare with animal rights. Animal welfare is related to the wellbeing of animals, which is something we can quantify using objective methods, like measuring an animal’s behavior, physiology, or health status. In contrast, animal rights are ethical views of how animals should be treated, which are debated and decided on by people depending on their moral values. As discussed earlier, several philosophical approaches have been developed to establish what the most ethical way to treat animals is. Regulations on animal welfare are often based on these kinds of ethical considerations. Concerns about the suffering of livestock animals have prompted many governments to establish regulations designed to improve their wellbeing. The legislation in many countries is based on the Five Freedoms proposed in a 1965 report prepared for the British government. This report states that animals should have the following five freedoms: (1) freedom from hunger and thirst; (2) freedom from discomfort; (3) freedom from pain, injury, or disease; (4) freedom to express their normal behavior; and (5) freedom from fear and distress [10]. Based on these five freedoms, legislation has been crafted that stipulates the minimum requirements for rearing, transporting, and slaughtering livestock animals. However, the regulations in many countries have been criticized because they are not tough enough, or are not enforced, and therefore there is still a considerable level of animal suffering. As an example,

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the “Humane Methods of Slaughter Act” in the United States regulates how livestock animals should be handled and killed. When using a captive bolt stunner, which is a device that delivers an intense punch to the forehead of an animal, these regulations state that the “animals shall be stunned in such a manner that they will be rendered unconscious with a minimum of excitement and discomfort” “before they are shackled, hoisted, thrown, cast, or cut.” Note, this procedure is not meant to kill an animal, just to make it unconscious. The abattoir wants the animal’s heart to be still beating when it is strung up and its jugular veins and arteries are severed, so the blood will pump itself out. Death by this process, known as exsanguination, has been reported to take from around 1 to 2 minutes, provided all goes well. The USDA recognizes that the “stunning operation is an exacting procedure and requires a well-trained and experienced operator.” This is grueling work that is performed under harrowing conditions, and like all human activities, it is not always possible to carry it out perfectly. Given, that nearly 34 million beef cows are “processed” in slaughterhouses every year [11], an appreciable number of them are not fully unconscious when they are strung up, cut, and drained of blood. Researchers have reported that it is often difficult to conclusively determine whether an animal is unconscious by simply looking at it [12]. So, there is a chance the animal is still alive when processing is carried out. For this reason, these researchers recommended “sufficient time should be left for the animal to die following exsanguination before starting invasive dressing procedures such as scalding or skinning.” A survey of people working in the livestock industry with pigs reported that the vast majority of them (nearly 96%) were uncomfortable with the methods they were using to kill livestock animals, partly because they detected some level of consciousness in the animals after stunning treatments [13]. Studies of the effectiveness of stunning methods have reported that around 4–15% of cattle still showed some signs of consciousness after the treatment [13, 14]. These signs include eyeball rotation, blinking, and rhythmic breathing. Just in the United States, this corresponds to millions of cattle every year still being conscious when their throats are cut or their bodies are dismembered. The numbers are much higher when pigs, sheep, and chickens are included. Even the use of electrical prods to coax animals from the trucks transporting them to the place where they will be killed is not banned. Instead, the government regulations state that they should be used “as little as possible.” The severe distress of the animals is therefore likely to increase as soon as they arrive at the abattoir. Having legislation governing animal welfare is certainly an important advance and is better than having no legislation at all, but it still does not

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solve the problem. Many livestock animals still endure a life of discomfort and suffering, as well as a stressful and painful death.

 owmageddon – What Would Happen C to Livestock Animals If We Stopped Eating Meat? If everyone decided to stop eating meat, what would happen to the billions of domesticated livestock animals that are now alive? Most of them could not survive in the wild. They have been bred for centuries to be docile and a source of food, rather than autonomous creatures that fend for themselves. Livestock animals are very different from the animals our ancient ancestors encountered in the wild (Fig.  3.8). Domestic cows are descended from aurochs, which were large wild herbivores that are now extinct but appear in the ancient cave paintings of prehistoric peoples. Domestic pigs descended from wild boars that lived in Europe and Asia. Genetic analysis suggests that domestic chickens are descendants of red junglefowl from Southeast Asia [15]. These ancient animals were able to forage for foods and protect themselves, but their domesticated counterparts would have little chance of surviving in the wild. Indeed, their lives would likely be nasty, brutish, and short as

Fig. 3.8  Modern livestock animals are descended from wild animals: chickens from red junglefowl (photo by Francesco Veronesi), pigs from wild boars (photo by Valentin Panzirsch), and cows from now extinct aurochs (photo by Jaap Rouwenhorst). (All images from Wikimedia Commons)

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they were attacked by predators or starved from lack of food. This means that humans would have to care for them throughout their lives, which would require considerable resources. This would only need to be done for one generation, provided the animals were not allowed to breed (but this may be cruel too). Alternatively, all the existing livestock could be euthanized, leading to one last giant global barbeque before we all became vegan or vegetarian. A pertinent ethical question might then be: is it better to live a happy life and then be killed quickly at the end, rather than living no life at all? There are also socioeconomic and ethical concerns associated with reducing or eliminating the farms that raise animals for food, the trucks that transport them, and the slaughterhouses that process them. What will happen to all the people who work in these industries if we stop eating meat, as well as to all the local communities that rely on them for salaries and taxes? The U.S. Department of Labor estimated there were nearly half a million people working in the meat and poultry industry in 2010. Any disruption to this industry would therefore have huge socioeconomic consequences. Ideally, livestock farms would be repurposed to produce more sustainable and ethical foods (like cereals, nuts, fruits, and vegetables), while processing facilities would be repurposed to convert alternative protein sources (like plants, microbes, or lab-grown meat) into food products. However, this is going to take time and will require support from local and federal governments to facilitate the transition. Thus, there are still important ethical issues that society needs to address even if we do decide not to eat meat anymore.

My Takeaway After viewing (far too many) photographs and videos of factory farms and abattoirs, reading about the suffering and distress experienced by animals living and dying in these facilities, and considering the huge number of livestock animals involved, I strongly believe that it is ethical to stop eating meat or at the very least to only eat meat from animals raised and killed humanely. Eating more foods produced from alternative protein sources would reduce the misery many chickens, pigs, sheep, and cows endure throughout their lives. Having said this, the alternative protein industry is only just emerging and is still a long way from competing with the meat industry. Consequently, it is still important to do everything we can to promote the wellbeing of the animals living on farms and killed in abattoirs. Ideally, they would not have to be raised in factory farms, but this would increase food costs and lead to more

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environmental damage, leading to other ethical concerns. We must also recognize there are ethical issues associated with producing alternatives to meat. For instance, some animals, birds, and insects will always be harmed or killed when agricultural crops are raised, stored, and distributed because of the mechanical machinery (like combine harvesters) and pesticides required to grow and harvest them. These collateral deaths will, however, be larger if we continue eating meat because most agricultural crops are currently grown to feed livestock animals rather than humans. In terms of ethics, each of us must make our own decisions about eating meat based on what we value most. I cannot eat meat now because I find the thought of putting animal flesh into my mouth to be repulsive – after learning about the plight of animals in the modern livestock industry, I can no longer dissociate the food on my plate from the animal in the farm.

References 1. Ursin, L., The Ethics of the Meat Paradox. Environmental Ethics, 2016. 38(2): p. 131–144. 2. Feldmann, D., et al., Influencing Young America to Act. 2021, Cause and Social Influence. p. 1–5. 3. yourdictionary.com. 4. Alvaro, C., Ethical Veganism, Virtue Ethics, and the Great Soul 2019, Lanham, Maryland: Lexington Books. 5. Alvaro, C., Raw Veganism: The Philosophy of the Human Diet. 2020, New York, N.Y.: Routledge. 6. Rossi, J. and S.A. Garner, Industrial Farm Animal Production: A Comprehensive Moral Critique. Journal of Agricultural & Environmental Ethics, 2014. 27(3): p. 479–522. 7. Alvaro, C., Ethical Veganism, Virtue, and Greatness of the Soul. Journal of Agricultural & Environmental Ethics, 2017. 30(6): p. 765–781. 8. Alvaro, C., Veganism as a Virtue: How compassion and fairness show us what is virtuous about veganism. Future of Food-Journal on Food Agriculture and Society, 2017. 5(2): p. 16–26. 9. Bobier, C.A., What Would the Virtuous Person Eat? The Case for Virtuous Omnivorism. Journal of Agricultural & Environmental Ethics, 2021. 34(3). 10. Delvendahl, N., B.A.  Rumpold, and N.  Langen, Edible Insects as Food–Insect Welfare and Ethical Aspects from a Consumer Perspective. Insects, 2022. 13(2): p. 121. 11. USDA. Cattle: Commercial Slaughter Number of Head by Month and Year, US. 2022 [cited 2022 June 11, 2022]; Available from: https://www.nass.usda. gov/Charts_and_Maps/Livestock_Slaughter/caheadx1.php.

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12. Verhoeven, M.T.W., et al., Indicators used in livestock to assess unconsciousness after stunning: a review. Animal, 2015. 9(2): p. 320–330. 13. Dalla Costa, F.A., et al., On-farm pig dispatch methods and stockpeople attitudes on their use. Livestock Science, 2019. 221: p. 1–5. 14. Kaluza, M., et al., Reduction of the occurrence of incorrect stunning and the occurrence of reflexes and reactions in cattle after pneumatically powered captive-bolt stunning in comparison with cartridge-fired captive-bolt stunning. Animal Science Journal, 2022. 93(1). 15. Hata, A., et al., Origin and evolutionary history of domestic chickens inferred from a large population study of Thai red junglefowl and indigenous chickens. Scientific Reports, 2021. 11(1): p. 2035.

4 Meat and Nutrition

Abstract  There may be appreciable health implications from switching from an omnivore diet to one containing less meat, such as a flexitarian, vegetarian, or vegan diet. This chapter discusses the impact of foods on human health and wellbeing, as well as the events that occur when foods pass through our gastrointestinal tracts and are absorbed by our bodies. It then considers the evolution of the human gastrointestinal tract and whether we were designed to eat meat or not. The macronutrient and micronutrient compositions of omnivore and meat-free diets are different, which can have important nutritional and health implications. The role of different macronutrients (proteins, fats, and carbohydrates), micronutrients (iron, zinc, calcium, vitamin B12, vitamin D), omega-3 fatty acids, dietary fibers, and nutraceuticals on human health and wellbeing is therefore discussed. It is often assumed that a plant-based diet is better for our health, but this depends on the types and amounts of foods we eat. A meat-free diet may be more or less healthy than an omnivore one depending on whether you are eating fruit, vegetables, nuts, and whole grains or eating plant-based burgers, French fries, cookies, and potato chips. The concept of unhealthful and healthful plant-based diets is therefore introduced. Keywords  Macronutrients • Micronutrients • Dietary fiber • Omega-3 fatty acids • Phytochemicals • Health • Nutrition Let food be thy medicine and let thy medicine be food. Hippocrates

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 D. J. McClements, Meat Less: The Next Food Revolution, Copernicus Books, https://doi.org/10.1007/978-3-031-23961-8_4

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Is Eating Less Meat Healthier? Like all of us, I want to live a happy and healthy life. Preferably a long one. Would eating less meat make me healthier? Many people decide to become vegetarians or vegans because they believe it will make them slimmer, fitter, or less likely to suffer from diseases, such as diabetes, cancer, or heart disease. But is this true? I have read magazine and newspaper articles telling me a plant-­ based diet will make me healthier and others saying it will make me sicker. I therefore decided to dig into the scientific and medical literature and find out for myself. As with many things to do with nutrition, the picture turns out to be much more complex and nuanced than I first expected. How do we judge if we are healthier on one diet than another? There are several things we might consider. Absence of disease. Feeling better. A healthier body weight. Living longer. Some of these things can easily be measured, whereas others are quite subjective. I will therefore begin by considering what “health” is and how it might be affected by what we eat.

What Is Health? Everyone tends to take their health for granted, until something goes wrong. So far, I have been quite lucky and only suffered from minor illnesses, such as back pain, toothache, flu, and hangovers. But even when I am in the midst of these minor complaints I am pining to be well again. This urge is even greater for people suffering from debilitating conditions such as cancer, heart disease, hypertension, or diabetes. But good health is more than just the absence of illness – it also involves general wellbeing, such as a good mood and feelings of vitality. A healthy body is one where all the interlocking biological systems are functioning properly, at the molecular, cellular, tissue, organ, and body levels. Our bodies are truly amazing. They are complex and dynamic soft machines that build and maintain themselves throughout our lifetimes using only air, water, and food (and the occasional pharmaceutical intervention). Our bodies contain trillions of cells that all unconsciously coordinate their activities to keep us alive and kicking. But how does what we eat affect our bodies and our health?

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How Does Food Affect Our Health? Our bodies are mainly comprised of water, protein, and fat, with smaller amounts of carbohydrates, minerals, genetic materials (DNA and RNA), and other minor substances. These molecules are assembled into cells, which form tissues (brains, hearts, lungs, livers, kidneys teeth, skin, and bones) that carry out all the different functions we need to grow and survive. Food is critical because it provides the building blocks our bodies need to replace the parts that are running out, as well as the fuel to keep our bodies working. This fuel is needed to keep us warm, to power our muscles and brains, and to provide the energy that keeps our cells functioning. The foods we eat also play a critical role in our mental health and energy levels – whether we feel happy or sad, vital or exhausted. As humans, we cannot eat anything – we can only eat those things our bodies can safely use as building blocks or fuel. If you tried to live by eating grass alone (like a cow does), you would quickly die of starvation because your body does not have the enzymes needed to break down the cellulose in the grass. Even so, our gastrointestinal tract has adapted through evolution to efficiently break down a wide variety of substances we encounter in our environment so they can be absorbed and utilized by our bodies [1]. Historically, this included meat, insects, fruit, vegetables, leaves, nuts, and cereals. Now, it may also include hamburgers, veggie sausages, pizzas, cookies, pasta, candies, and bread. It is incredible that our guts have evolved to digest and absorb such a wide diversity of foods. This dietary flexibility is unlike most other animals, which have much more limited diets, like cows who mainly live off grasses and big cats who mainly live off meat. Our dietary dexterity has allowed us to live and thrive in extremely diverse environments around the world, including the icy cold tundra of the Arctic Circle, the barren deserts of Northern Africa, the luxuriant rainforests of the Amazon, and the temperate climates of Northern America and Europe.

Fantastic Voyage: From Our Foods to Our Bodies Before nutrients can be used to build and power our bodies, the foods we eat must be disassembled inside our guts, absorbed into our bloodstreams, and then distributed to our tissues and organs. To understand the differences between meaty and meat-free diets on our health, it is therefore important to understand our guts. Many of us have a negative opinion of our guts – we

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only become aware of them when they are causing us problems – stomach cramps, bloating, constipation, diarrhea, or excessive flatulence. In reality, our guts are performing minor miracles every day. They protect us from harmful substances that may be hidden in our foods, and they help us to break down foods so we can efficiently absorb and use their nutrients. If you look at any part of your body, it is made almost entirely from the foods you have eaten. To understand how different foods affect our health and wellbeing, we must understand their journey through out guts (Fig. 4.1). The journey begins when a food enters our mouth, then continues as it passes through the fleshy tunnels and cavities of our esophagus, stomach, small intestine, and colon. Finally, it ends when the remnants of our foods pass through our anus and into our toilet bowl. The human gut has been designed to protect us from any harmful substances we might put into our mouths, like chemical toxins or pathogenic microbes that might be hidden in the foods we eat. Of course, it

Ingestion (M (Mouth) M th) Pla Plant-based lant-based burger

Fragmentation tatio (Mouth and stomach)

Dissolution (Stomach and small intestine)

Lipid, protein, and carb carbohydrate r ohydrate produ d cts digestion products

Fig. 4.1  Foods are broken down by mechanical, chemical, and enzymatic processes inside our bodies, absorbed into our bloodstreams, and then distributed to our organs and tissues where they are used to build and power our bodies. (Images: Creative Commons – see Figure Permissions)

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Proteins

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Proteases Prote Pr t as a es e Amino Acids

Mucus Enterocytes

Amylases Amy m la lases e Carbohydrates Sugars Lipase Lip i as ae Fats Fatty Acids

Fig. 4.2  The proteins, carbohydrates, and fats in our foods are digested by enzymes in our gastrointestinal tracts and then absorbed by the epithelium cells that line our small intestines. (Images: Creative Commons – see Figure Permissions)

is also designed to break down our foods into a form that we can absorb. It does this using a combination of grinding motions, chemicals, and enzymes that break the foods into smaller pieces and eventually into tiny molecules that can pass through the cells lining our guts so they can be absorbed by our bodies (Fig. 4.2). Our teeth seem to have evolved to bite, chew, and grind both fibrous plant materials and fleshy animal tissues. In the mouth, solid foods like meat or its replacements are mixed with saliva and chewed to form a slimy “bolus” that slips down our throats when we swallow. These foods are then further broken down inside our stomach due to its muscular churning motions. Before I started working in this area, I never realized that my stomach was in continuous motion, expanding and contracting to fragment, mix, and transport the foods inside me. Our gastric fluids also contain strong acids (hydrochloric acid) and enzymes that further break down our foods. After about 2  h of churning within this muscular bag of acidic fluids, the partially digested food (“chyme”) is squirted through a small hole (the weirdly named “pyloric sphincter”) at the far end of our stomachs into our small intestines. Our small intestines look like giant earthworms coiled up inside us. They consist of a fleshy tube that pushes the chyme towards our colons using a wave-like (“peristaltic”) motion. They have been designed by evolution to be relatively long and have an extremely high surface area, since this increases the rate at which nutrients are absorbed by our bodies. This large surface area is achieved by having multitudes of tiny fingerlike projections (villi) on the surfaces of our gut linings (Fig. 4.2). As the chyme enters our small intestines,

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our bodies inject intestinal juices into them that contain a cocktail of digestive enzymes, natural detergents (bile salts), and other substances that carry out the final stages of disintegration and dissolution of the food. Proteases, lipases, and amylases break down proteins, fats, and starches into their basic building blocks so they are small enough to be absorbed by our bodies (Fig. 4.2). The bile salts act like washing-up liquid. They help to solubilize the digested fats and carry them to the walls of our guts where they can be absorbed (just like washing-up liquid contains detergents that solubilize the dirt on our plates and carries it down the sink). As a result of these evolutionary design features, most of the nutrients we need to survive are absorbed by our small intestines. However, some of the substances we eat cannot be broken down in our mouths, stomachs, or small intestines because our bodies are unable to produce the forces or enzymes needed to dissemble them. Consequently, they move into our colons where they may be broken down and fermented by the trillions of bacteria residing there (aka the “gut microbiome”).

Gut Evolution: Are We Designed to Eat Meat? Our guts have evolved over hundreds of millions of years to efficiently extract the nutrients our bodies need to grow and function, as well as to protect us from any harmful things we consume, such as pathogenic microbes and toxins. If we look back through the vast expanses of the history of life on earth, it is hard to establish exactly how and when the gut developed. But evolutionary biologists are getting some intriguing insights by combining modern genetics with studies of the design of the digestive systems of different animals [2, 3]. We all evolved from single-cell microorganisms that swam around in the primordial broth. These simple microbes did not have a gastrointestinal tract. Instead, they simply absorbed nutrient-rich fluids from their surroundings, turned them into energy and building blocks, and then excreted any waste products. Somehow, families of these microbes clustered together to form communities, which eventually became the first multicellular organisms. Over time, certain kinds of cells in these organisms specialized in one function while others specialized in another, eventually allowing the development of different kinds of organs and tissues, like hearts, livers, kidneys, muscles, skin, eyes, brains, and digestive tracts. At some point in history one multicellular organism consumed another, leading to the first example of carnivory. But we do not know when, where, or how this happened and who the “animals” involved were.

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Some people who argue against a vegan or vegetarian diet believe we are designed by evolution to eat meat. But has evolution really hard-wired us to be omnivores, vegetarians, or vegans? A team of scientists based in Italy recently published an article on the “Development and evolution of gut structures.” They state that “the emergence of a specialized system for food digestion and nutrient absorption was a crucial innovation for multicellular organisms.” Indeed, the same general pattern of mouth, esophagus, stomach, intestine, and anus is found in a wide range of species, including sea urchins, flies, worms, mice, and us. In addition, these diverse species have similar kinds of cells that carry out similar specialized functions, such as producing enzymes and hormones that regulate food digestion and energy balance. Despite the many similarities in the overall design of their gastrointestinal tracts, there are some important differences between species depending on what they have evolved to eat. Omnivores like pigs have a digestive tract with a mouth, stomach, small intestine, and large intestine that is very similar to ours. The digestive tracts of herbivores, like cows and sheep, have many similar features to ours but they also contain a specialized region known as the rumen that contains microorganisms that turn cellulose-rich substances (like grass or hay) into sugars that the animals can then use as nutrients. Birds, like chickens and turkeys, have other specialized regions, such as the crop to store and soak food, and the gizzard that contains small stones that grind their foods into small pieces, which is important because birds don’t have teeth. There are also differences in the diets of our closest relatives on the evolutionary tree [4]. Most nonhuman primates are omnivores, but they tend to eat mainly plant-based foods (such as fruit and leaves), with only small amounts of insects and meat. Chimpanzees and baboons typically eat the most meat, whereas lemurs and colobines eat the least. Even so, the amount of meat consumed by these animals is typically much lower than that found in the human hunter-gatherer diet. It is hypothesized that primates evolved to include meat in their diet as a source of energy, proteins, vitamins, and minerals. In environments where high-calorie plants were not readily available, it would have been an evolutionary advantage to consume more meat. These studies suggest that primates, including humans, evolved gastrointestinal tracts that were mainly designed to process plants but were also capable of digesting and absorbing meat. In some environments, this was essential for the survival of our species. However, it does not mean we have to eat meat to survive now. We can now get adequate amounts of energy, proteins, vitamins, and minerals from plant-based foods. Some primates participate in murder, cannibalism, rape, and incest, but we would not consider these to be traits that are natural or desirable to the modern human.

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There are other sources of evidence from anthropology that provide more insights into the evolution of meat eating by humans. Prof. Mann is an Australian anthropologist who has examined the fit between our bodies and our diets [5]. In his article on “Meat in the human diet” he quotes Prof. Boyd Eaton: We are the heirs of inherited characteristics accrued over millions of years, the vast majority of our biochemistry and physiology are tuned to life conditions that existed prior to the advent of agriculture. Genetically our bodies are virtually the same as they were at the end of the Paleolithic period. The appearance of agriculture some 10,000 years ago and the Industrial Revolution some 200 years ago introduced new dietary pressures for which no adaptation has been possible in such a short time span. Thus, an inevitable discordance exists between our dietary intake and that which our genes are suited to.

Anthropologists have gathered evidence from a diversity of sources to try to understand what our ancient ancestors ate [1, 5, 6]. They have looked at changes in our anatomy, particularly our brains, jaws, teeth, and gastrointestinal tract over time, as well as comparing our anatomies to those of our close relatives (such as gorillas and chimps). They have examined the dietary pattern of existing hunter-gatherer societies from around the world. They have studied the energy requirements associated with developing a large brain compared to body size. These findings suggest that sometime in the past, which is believed to be around 3–4 million years ago, our ancestors switched from a diet poor in energy and nutrients, and rich in fibrous materials, to one that contained more energy- and nutrient-dense animal foods [1]. As a result, the Homo sapiens of the Paleolithic period became meat eaters that were top-­ level carnivores. When scientists study the fossil remains of our ancient ancestors (hominids), they find that their teeth and jaws changed from being designed to consume coarse fibrous plant materials to becoming more generalized to eat a mixture of fruits, nuts, and animal flesh [1, 5]. Similarly, evidence from fossil isotope ratios is consistent with hominids changing from eating large amounts of fibrous plant materials to eating grazing animals that lived off grasses. Strong evidence for evolution to meat eating also comes by comparing the anatomy of our gastrointestinal tracts to those of animals that only eat plants (herbivores like cattle, horses, or gorillas) or that only eat meat (carnivores like big cats). Typically, herbivores have large stomachs and colons, which helps them break down fibrous plant materials and convert them into energy. Conversely, carnivores have highly acidic stomachs and an extended small

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intestine, which allows them to efficiently digest and adsorb muscle tissues. The anatomy of the human gut fits somewhere between that of strict herbivores and strict carnivores, indicating that we are indeed omnivores who developed to eat a wide range of different kinds of food. The size of our brains relative to our bodies is another indication that our ancient ancestors evolved to eat meat. Like other primates, our brains are relatively big compared to our bodies. The precise origin of this effect is still unclear, but several interesting hypotheses have been put forward. The brain needs a lot of energy to run and also requires certain unique food components to build it, such as omega-3 fatty acids, which mainly come from meat. One hypothesis is that to have a big brain, the body had to reduce the size of another major body organ – the gut. When we started eating foods with a higher nutritional and energy content and that were easier to digest, then we did not need such a big gut. As our guts shrank, our brains grew. This was probably an iterative process driven by small evolutionary advantages that accumulated over millennia. It has also been proposed that cooking foods, especially meat, enabled us to grow bigger brains because then they were easier to digest, thereby releasing more calories [7]. Meats contain high levels of proteins and fats, especially the omega-3 fats needed to build brains, and so it seems possible that as our ancestors started moving from forests to grassy savannas, they started to eat more meat. Analysis of the diets of some existing hunter-gatherer societies indicates that they get the majority (>60%) of their calories from animal products, which is not surprising from a cost-benefit analysis of the foraging process. Overall, the amount of time and energy required to get a certain quantity of calories and nutrients from an animal source is typically much less than that required to get it from a plant source. This is because the plant-based foods available to our ancient ancestors were often difficult to digest and had a low energy density, such as wild roots, vegetables, nuts, and fruits. These foods would be nothing like the ones produced by modern agriculture that we can simply pick up from a local supermarket or restaurant. There are other clues from our metabolism that suggest that the human physiology is adapted to eat meat. For instance, there are certain components in fats (ω-3 fatty acids) and proteins (taurine) that are essential for human health, which can normally only be obtained from animal or fish sources. It is hypothesized that humans did not need to synthesize these components themselves because they were regularly getting them from their diet. Finally, there is evidence from parasites. Parasites tend to co-evolve with their hosts. Certain kinds of parasites (Taeniidae) co-evolved with carnivores and are spread by eating meat. Some of the parasites found in this family use humans

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exclusively as their hosts, which suggests there must have been a substantial period in history when early humans or their ancestors were meat eaters. At the end of his review of Paleolithic diets, Prof. Mann concluded “there is no historical or valid scientific argument to preclude lean meat from the human diet, and a substantial number of reasons to suggest it should be a central part of a well-balanced diet.” Our ancient ancestors lived in a very different environment than we do now, where eating meat (especially cooked meat) gave them an evolutionary advantage that helped them evolve into the species we are today. We live in houses, travel in cars, busses, trains, and airplanes, watch TV, surf the Internet, and get our foods from supermarkets and restaurants. Moreover, the types of foods available to us today are very different – our foods are much more abundant, calorific, nutrient rich, and digestible than those available to our ancestors. So, it is not just meat that our genetic profile is not adapted to, it is almost everything! The wonderful thing about evolution is that it has made us incredibly adaptable creatures, which is one of the reasons we have been able to survive in so many different ecological niches around the globe throughout history. Our ancestors may have evolved to eat meat, but we can certainly live without it (as demonstrated by the billions of people who have been born, lived, and died vegetarians or vegans). We can get the nutrients that our ancestors got from animal sources, such as iron, zinc, ω-3 fatty acids, and vitamin B12, from other sources now. Moreover, our ancestor’s main problem was food scarcity, whereas for most of us living in developed countries today it is food overabundance.

The Agricultural Revolution: Going Backwards Our species experienced a profound change in its diet around 10,000 years ago due to the Agricultural Revolution [5]. Many humans made a transition from hunting and gathering in relatively small tribes to growing and cultivating wild cereal crops. As a result, they tended to live in a particular location for extended periods so they could cultivate and harvest their crops, which eventually led to the development of the first towns and cities. One might expect that this increased access to food would have made our ancestors healthier, but in fact, there is strong evidence that it made them less healthy. People living in early agriculture societies appeared to be shorter and have worse bones and teeth, more nutritional deficiencies, and more infectious diseases than the hunters and gatherers who preceded them. This change in health has been attributed to a switch from a diverse diet consisting of wild

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animals (deer, antelope, and gazelle), nuts, fruits, root plants, and wild pulses, to a more nutritionally restricted diet consisting largely of cereal crops, such as wheat, oats, barley, rice, or corn, depending on the geographical location. Thus, people went from eating a diet high in protein, omega-3 fats, and dietary fiber containing a diverse range of nutrients to a diet consisting largely of digestible carbohydrates containing a much narrower range of nutrients. As a result, early agricultural societies were more prone to nutritional deficiencies and disease than hunters and gatherers. I was surprised when I found this out. I had always assumed that people living in cities would be healthier than those in the wild. So why did our ancestors make this transition? I think they must have got caught in a history-trap – once they had settled down and established large towns, it was difficult for them to go back to hunting and gathering – there would have been too many people to support and too many possessions to move. Over the past 200 years or so there has been another dramatic change in our diets, which started with the industrial revolution and has continued to the highly processed mass-produced foods many of us consume today. Modern food processing methods, such as milling, refining, and thermal processing, often remove or destroy valuable dietary fibers, phytochemicals, vitamins, and minerals. As a result, many of our foods are highly palatable and safe, but also calorie-dense, nutrient-poor, rapidly digestible, and full of fat, sugar, and salt, which is leading to modern diseases such as obesity, diabetes, heart disease, and cancer. Professor Mann compared the estimated daily intake of nutrients by our Paleolithic ancestors to that of modern humans living in the United States (Table  4.1). He found that modern humans eat much less protein, dietary fiber, and vitamins than their ancient ancestors, but much more fat, salt, and carbohydrate. This suggests that our ancestors had a healthier diet than most of us have today.

 an We Get All the Nutrients We Need C from a Meat-Free Diet? If we are going to switch from an omnivore diet to a vegan or vegetarian one, then it is important there are not any adverse nutritional and health consequences. Here, I focus on replacing meat with plant-based foods, since these are currently the most widely consumed alternatives to meat. In general, we require fats, proteins, carbohydrates, vitamins, and minerals to provide the

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Table 4.1  Comparison of the estimated daily intake of nutrients of our Paleolithic ancestors and that of modern humans living in the United States Nutrient Macronutrients (% energy) Protein Carbohydrate Fat Vitamins (mg/day) Vitamin B1 (thiamine) Vitamin B2 (riboflavin) Vitamin B9 (folate) Vitamin C (ascorbate) Vitamin A (retinols) Vitamin E (tocopherols) Minerals (mg/day) Iron Zinc Calcium Sodium Potassium Dietary fiber (g/day)

Paleolithic

Modern

37 41 22

15 51 34

3.9 6.5 0.36 604 2870 32.8

1.5 1.7 0.18 93 1300 8.5

87 43 1956 768 10,500 104

10.5 12.5 750 4000 25,000 15

Adapted from Mann [5]

energy and building blocks we need to grow and live. However, we have quite a lot of flexibility about how much of these different nutrients we require and where we get them from, provided we exceed certain minimum thresholds. During a meeting with my research group, one of my students presented some data on the nutritional content of plant-based products on the US market. She showed a plant-based cheese that contained almost zero percent protein and had very high levels of saturated fats and salts. I was really surprised – when I think about cheese, I think of it as being a good source of protein and micronutrients. This led me to look at the nutritional profiles of other kinds of commercial plant-based foods, such as seafood and meat analogs. I found some plant-based salmon products containing less than 2% protein instead of the 20% or so found in real salmon. But I also found other plant-based salmon products with protein levels much closer to those found in real salmon. The ones with low protein contents tended to use starch as a replacement, which is a digestible carbohydrate that might contribute to high blood glucose levels and diabetes. In general, the plant-based products varied widely in their nutritional contents, even within the same category, and were often very different from the animal source foods they were designed to replace (Table 4.2). This could have important nutritional consequences. If someone replaced the seafood in their diet with a plant-based alternative that was much lower in protein and omega-3 fats but much higher in salt, starch,

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Table 4.2  Representative examples of typical nutritional profiles of commercial real and plant-based salmon Per 100 g Energy (kcal) Protein (g) Total fat (g) Saturated (g) Monounsaturated (g) Polyunsaturated (g) Cholesterol (mg) Total carbohydrate (g) Sugars (g) Dietary fiber (g) Calcium (mg) Iron (mg) Sodium (mg) Zinc (mg) Vitamin D (μg) Vitamin B12 (μg)

Real salmon

Plant-based salmon (#1)

Plant-based salmon (#2)

131 22.2 4.7 0.8 1.4 1.1 51 0

160 2 4 0.7a 0.4a 3.3a 0 32

211 14 14.1 2.1 – – 0 6

0 0 9 0.43 78 0.46 14.1 4.7

0 6 24 0 520 – – –

1 4 56 2.5 535 – – –

Given per 100 g of product. Data from the USDA food database for real salmon and plant-based salmon (#1). Data from Internet for plant-based salmon (#2) a Calculated for olive oil assuming 72% MUFA, 11% PUFA, and 17% SFA

and saturated fat, this could have a detrimental effect on their health. Of course, this does not have to be the case, plant-based foods can be designed to have nutritional profiles that are equivalent to, or even exceed, those of animal-­based ones. However, it is important that food manufacturers design their products to be nutritious and healthy, and not just to be tasty, convenient, and affordable. Most of us living in developed countries get more than enough calories in our diets. Indeed, we often get far too many, which leads to overweight and obesity. However, some nutritionists have expressed concerns about a lack of certain kinds of nutrients in a vegan or vegetarian diet, especially some vitamins (vitamin B12 and D) and minerals (iron and zinc), as well as proteins and omega-3 fatty acids. I wanted to find out how much of an issue this really was, and so I turned to recent studies on the differences in nutrient profiles of animal- and plant-based diets. A study published in 2021 reported that Canadians who got the majority of their protein from plant sources had daily protein intakes that were either around or below those recommended by the Canadian government, i.e., 0.8 g of protein per kilogram of body weight per day (g/kg/day) (Fig.  4.3) [8]. Those with the highest level of plant proteins in their diet (75–100%), which

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Plant Protein in Diet (%)

Impact of Protein Source on Protein Intake

Percentages of population who eat different levels of plant-proteins

Total

75-100%

Corrected

3.4% 15.5% 29.9%

50-75%

25-50%

0-25%

0

0.2

0.4

0.6

0.8

1

1.2

Protein Intake (g/kg BW/day)

1.4

51.2% 0-25%

25-50%

50-75%

75-100%

Plant Protein in Diet (%)

Fig. 4.3  Levels of total and available (corrected) daily protein intake in Canadian consumers that have different percentages of plant proteins in their diet. (Charts replotted from data reported in Marinangeli et al. [8])

constituted about 3.4% of the population (probably vegans), had corrected protein intake levels well below (0.54  g/kg/day) the recommended levels. Even those who got the majority of their proteins from plants (50–75%) but still got a significant percentage from animals, which constituted about 15.5% of the population (probably vegetarians and flexitarians), were just above the borderline (0.81  g/kg/day). For some segments of the population, such as infants, the elderly, and athletes, significantly higher levels of protein are recommended (around 1.2 g/kg/day), and so some of these people may also be at risk of a protein deficiency [9]. The low corrected protein intake for vegans and vegetarians is mainly a result of the lower amount, digestibility, and quality of proteins in plant-based foods compared to those in animal-based ones, like meat, seafood, eggs, or milk. Thus, an appreciable fraction of Canadians may not be getting enough protein in their diet, which could lead to undesirable health consequences. Ciaran Forde and Rachel Tso, who are clinical nutrition researchers working in Singapore, recently highlighted some of the other unintended nutritional consequences that might arise when switching from an animal- to plant-based diet [10]. They compared the differences in essential vitamins and minerals obtained from model omnivore, flexitarian, vegetarian, and vegan diets. These diets were designed so that the total number of calories and macronutrients in each of them was fairly similar. In the low or no meat diets, they also examined the impact of replacing the meat with traditional

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plant-based foods (like tofu, bean burritos, eggs, fruits, vegetables, and nuts) or with next-generation plant-based foods (like meat, egg, and dairy analogs). The researchers found that all the diets with the traditional plant-based foods (except the purely vegan one) met the daily requirements for essential micronutrients. In contrast, the diets containing the next-generation plant-based foods had levels of calcium, potassium, magnesium, zinc, and vitamin B12 below recommended values, and levels of saturated fat, sodium, and sugar above recommended values, which could have adverse health effects. The Singaporean researchers highlighted that many plant-based foods currently have a “health halo” around them – consumers believe they are eating something that is healthier for them. In reality, most of the scientific evidence for the health benefits of a plant-based diet is from studies of people who eat traditional vegetarian or vegan foods (like fruits, vegetables, legumes, and nuts), rather than the new generation of highly processed meat, seafood, egg, and dairy analogs. In another recent study, this time carried out in the United Kingdom, researchers examined the nutritional implications of reducing the amount of meat in the diet [11]. They found that replacing meat with meat alternatives led to an increase in carbohydrate, dietary fiber, sugar, and sodium intake but a reduction in protein, total fat, saturated fat, iron, and vitamin B12 intake. The nutritional consequences of eating less meat may therefore be beneficial or detrimental to human health. Eating more dietary fiber and less saturated fat should improve health, whereas eating more sugar and salt and less protein, iron, and vitamin B12 could have adverse health effects. This study also compared the effects of replacing meat with nutritionally fortified or unfortified meat alternatives. Fortification increased the level of proteins and micronutrients (such as iron and vitamin B12) consumed, which would be expected to improve the healthiness of a plant-based diet. Consequently, there are compelling reasons for the food industry to fortify their meat alternatives with nutrients that might be missing from a plant-based diet. Taken together, these studies suggest that there may be some undesirable nutritional consequences from adopting a more plant-based diet if the foods used to replace meat are not chosen carefully. Ideally, consumers should read the labels of plant-based foods before buying them and only select those products that are healthy. Of course, many people do not have the time or inclination to read the labels of every product they buy, or the nutritional knowledge to make informed decisions on the information provided. Consequently, it would be better for the food industry to design their plant-based products to contain all the nutrients required. Otherwise, the health of the general population may decline.

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In the following sections, I examine the importance of specific kinds of nutrients in the diet and highlight some of the risks and benefits that might be associated with transitioning to a more plant-based diet.

Macronutrients The macronutrients in foods are those nutrients that are usually present at the highest levels, such as proteins, fats, and carbohydrates. They are typically the main source of calories in our diets, as well as important sources of the building blocks our bodies need to grow and survive, like amino acids, fatty acids, and sugars. After we ingest them, the macronutrients are usually broken down by digestive enzymes in our gastrointestinal tracts, which are small biological machines designed by evolution to cut these large molecules into miniscule fragments that our bodies can adsorb (Fig. 4.2).

Proteins Animal- and plant-based products differ in the types and amounts of proteins they contain, which has nutritional implications. This is not surprising because evolution has designed the proteins in plants to do different things than the ones in animals. For instance, muscle proteins are designed to help an animal move around, whereas storage proteins in plants are designed to provide a source of energy and nutrients when the plant grows. Some of the main ways animal and plant proteins vary and their nutritional implications are summarized here: Amino Acid Profiles  Proteins are natural polymers consisting of strings of amino acids linked together like the pearls in a necklace (Fig. 4.4a). The number, type, and sequence of these amino acids depend on the origin of the proteins. In nature, there are 20 different amino acids commonly found in proteins. Some of these amino acids can be made inside our bodies from other substances we have eaten, which are therefore referred to as non-essential amino acids because we do not need to obtain them directly from our diet. In contrast, other amino acids cannot be made in our bodies and so we must get them from our diets, which are therefore referred to as essential amino acids. There are nine essential amino acids: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Animal proteins typically contain all the essential amino acids we need, which is not

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Animal or Soy Protein

Legume Protein L L

L

M

L

LM

L M

L L

Cereal Protein L M

L

M M

M

LM

M

M

M

L L

M

M

L Methionine Deficient

Non-essential Amino Acid

Essential Amino Acids

Lysine Deficient

L Lysine M Methionine

Fig. 4.4a  Highly schematic diagram of protein composition. Proteins in foods contain a mixture of non-essential and essential amino acids. Different essential amino acids may be limiting like methionine (M) or lysine (L) depending on protein source

surprising because they are made from the same building blocks we are. In contrast, most common plant proteins (like those from cereals and legumes, but not soybean) lack one or more of the essential amino acids. This does not mean they do not contain them; it just means they are not present at high enough levels to meet all our nutritional needs. Cereal proteins like those in wheat, rice, barley, and oats have low levels of lysine, whereas legume proteins like those in peas, chickpeas, and lentils have low levels of methionine and cysteine [12]. If we only consumed one source of plant protein in our diet, we could therefore become sick from lack of essential amino acids. In practice, however, we tend to consume plant proteins from a variety of sources and so this is not a major concern. Interestingly, traditional food practices have arisen in many countries that address this issue. For instance, people in South America often eat rice (cereals) and beans (legumes) together so they would meet all their nutritional requirements for essential amino acids. In developed countries, most of us eat more than enough protein to meet our nutrient needs. Consequently, it is rare for us to be deficient in essential amino acids. As mentioned earlier, however, a recent Canadian study reported that people who got the majority (>75%) of their proteins from plants did not meet the government recommendations for protein intake, which could have undesirable health consequences [8]. This effect was partly attributed to the lower amount and quality of the proteins in plants compared to those in meat.

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Digestibility  The amounts of essential amino acids that we can absorb from our foods are sometimes limited by poor protein digestibility (Fig. 4.4b). In other words, even when foods contain sufficient essential amino acids, they may still not get into our bodies because the proteins are not fully broken down inside our guts. The proteins in meat tend to be highly digestible (90–95%), whereas those in plants tend to be less digestible (75–80%). However, when plant proteins are isolated from their natural environment and turned into food ingredients, then their bioavailability usually increases. There are several reasons for the relatively low bioavailability of the proteins found in some plant sources, like nuts, cereals, and legumes [13]. The individual protein molecules may be packed into compact structures and so the digestive enzymes in our guts cannot easily cut them into smaller fragments, e.g., gluten. The protein molecules may stick strongly to their neighbors and form dense aggregates, which again restricts the ability of our digestive enzymes to fragment them. The protein molecules may be trapped inside tough fibrous plant tissues that are resistant to digestion, and so they are not released, digested, and absorbed within our guts. Moreover, some edible plants contain antinutritional factors, like trypsin inhibitors and polyphenols, that inhibit protein digestion and absorption. If proteins are not fully digested

Protein

L

LM

L M

Protease

NON-ABSORBED

L

M

Peptides and Amino Acids L

L

ABSORBED

L

M M

L

M

Non-essential Amino Acids

L M

M

M LM

M

L

Essential Amino Acids

Fig. 4.4b  The proteins are cut into smaller fragments by digestive enzymes (proteases) in the human stomach and small intestine, which releases amino acids and peptides of different sizes. The amino acids and small peptides can be absorbed, but the larger peptides cannot

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in our stomachs and small intestines, then they will reach our colons where they can be metabolized by the bacteria living there, thereby altering our gut microbiome, which can have important health consequences. Some of these effects are discussed in more detail later in this chapter. Protein Quality  The overall nutritional quality of a protein therefore depends on the types and amounts of amino acids it contains (especially the essential ones), as well as the fraction absorbed by the body (bioavailability). The ability of different kinds of proteins to meet our nutritional needs can be classified by a score. Several scoring systems have been developed for this purpose. Historically, one of the most widely used measures of protein quality is the protein digestibility-­corrected amino acid score or PDCAAS (Table 4.3). A protein that fully meets the nutritional needs of humans is assigned a score of 100%, whereas one that is deficient in one or more essential amino acids is given a lower score. Most animal proteins have scores around or above 100%, whereas many plant proteins have much lower scores because they lack one or more essential amino acids or they are not fully digested and absorbed. As mentioned earlier, the quality of plant proteins can also be improved by blending them together to ensure they do contain all the required essential amino acids (such as combining rice and beans), and by processing them to ensure they are highly digestible and bioavailable. Soybeans are one of the few sources of plant proteins that have a high PDCAAS value and should therefore meet all our needs for essential amino acids.  A team of Dutch scientists recently examined the impact of eating plant versus animal proteins on the ability of our bodies to create new muscle tissue [14]. They reported that plant proteins tended to be less effective at creating new muscle than animal proteins. However, this effect depended on the total amount of protein conTable 4.3  Protein quality (PDCAAS) scores of some common animal and plant proteins, along with their limiting amino acids (taken from various sources) Protein source

PDCAAS

Limiting amino acids

Beef Chicken Milk Eggs Soybeans Kidney beans Chickpeas Peas Corn Rice Wheat

92% 100% 100% 100% 99% 68% 74% 60% 42% 73% 42%

Branched amino acids – – – Methionine, cysteine Methionine, cysteine Methionine, cysteine Methionine, cysteine Lysine Lysine Lysine

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sumed, as well as the age of the person. If you ate enough protein in your daily diet, or you were relatively young, then there was not a big difference. The authors attributed the worse muscle-building effects of the plant proteins to the fact they lacked some essential amino acids, and they were not fully digested. In the same study, the Dutch scientists reported the amounts of different kinds of plant- and animal-based foods that must be consumed to obtain a given amount of protein (Fig.  4.5). If you wanted to eat 20  g of protein, you would have to eat less than one serving of meat or fish, but 1–2 servings of peas or soybeans, 2–4 servings of corn or oats, and a whopping 3–6 servings of brown rice or potatoes. As a result, you would have to eat much more food, and therefore many more calories, if you only got your protein from fruits, vegetables, cereals, and legumes like in a traditional vegan diet (Fig. 4.6). This is a good argument for creating next-generation plantbased foods that contain protein levels like those found in meat and fish. Then consumers can get all the proteins they need, without having to eat too many other calories.

Fig. 4.5  Comparison of the amounts of different kinds of foods required to get 20 g of protein based on typical serving sizes. (Figure from Pinckaers et  al. [15] (Creative Commons, License 4.0))

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Fig. 4.6  Weights of different whole-food protein sources that need to be consumed to get 20 g of protein. (Figure from Pinckaers et al. [15] (Creative Commons, License 4.0))

Fats The fats from animal- and plant-based sources also vary considerably, which can have important nutritional implications. In general, most fats in foods are triglycerides, consisting of three fatty acids attached to a glycerol backbone. The fatty acids may have different lengths (short, medium, or long) and degrees of unsaturation1 (saturated, monounsaturated, and polyunsaturated), which impacts their physical, chemical, and nutritional properties (Fig. 4.7). According to current nutritional guidelines, consuming large quantities of saturated fats is considered to be bad for your health, whereas consuming high levels of unsaturated ones (especially polyunsaturated ones) is considered good. Nevertheless, this is certainly a gross simplification because there are many kinds of saturated and unsaturated fats, which have different nutritional and health effects. The fatty acid profiles of some common animal- and plant-derived fats are shown in Table 4.4. Fats derived from meat, especially beef and pork, tend to have high levels of saturated fat and low levels of  The degree of unsaturation refers to the number of double bonds a molecule has: zero (saturated), one (monounsaturated), and two or more (polyunsaturated). 1

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Fig. 4.7  The fats in our foods are made up from fatty acids, which vary in the length of their chains and the number of double bonds they contain (saturation). The double bonds are shown with blue arrows. These differences in the molecular characteristics of fatty acids impact their health properties and functionality in foods. Structures kindly drawn by Yuting Wang

polyunsaturated fats and would therefore be considered to be unhealthy. However, many nutrition scientists are now questioning the link between saturated fats and chronic disease and believe that the scientific evidence originally used to establish this link is weak [16]. Consequently, it is difficult to make a strong argument that increasing the level of saturated fats in the diet by reducing meat consumption will have major health benefits. The high saturated fatty acid content of animal fats means they tend to be solid-like at refrigerated and room temperatures, which often plays an important role in determining their eating quality. Fats derived from fish, especially fatty ones like salmon, tend to have much lower levels of saturated fats and higher levels of polyunsaturated ones, which is currently believed to be healthy. This difference is mainly because of the different environments that land and marine animals live in. Fish live in a much colder environment.

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Table 4.4  Fatty acid profiles of some common animal and plant fats Food type Animal-derived fats Beef Pork Poultry Salmon Milk Egg Plant-derived fats Algae Canola Coconut Corn Flaxseed Olive Palm Peanut Sunflower Soybean

Saturated

Monounsaturated

Polyunsaturated

37 40 29 18 61 29

59 48 44 30 31 43

2 11 21 50 2 23

16 6 90 16 10 12 48 16 10 14

18 56 7 31 20 78 40 38 14 23

46 36 2 53 70 8 10 41 75 58

Adapted from McClements and Grossmann (2021) [41]

Therefore, if more of their fats were saturated, they would solidify inside their bodies, and the fish would not be able to function properly. Most plant-derived fats tend to have relatively low levels of saturated fatty acids and high levels of unsaturated ones. Some plant-based fats have high levels of polyunsaturated fats (omega-3 ones), such as flaxseed and algal oils, which means they can be used as replacements for fish oil. A few plant-derived fats, notably coconut and palm oils, have high levels of saturated fats. This means they tend to be solid-like at ambient temperatures and melt in the mouth when heated. They can therefore be used to replace some of the functionality normally provided by animal fats. However, their high saturated fat content may also have nutritional consequences. As mentioned earlier, most nutrition scientists believe that consuming high levels of saturated fats is bad for you. For instance, the World Health Organization (WHO) recommends that we should get less than 10% of our total energy from saturated fats because of their link to coronary heart disease. However, some nutrition scientists suggest that the evidence that saturated fats are bad for our health is overblown [16]. The effects of saturated fat on human health are likely to depend on the length of the fatty acid chains (short, medium, or long), as well as what they are replaced with in our diets (e.g., monounsaturated fats, polyunsaturated fats, proteins, or carbohydrates) [17]. For instance, medium-­ chain saturated fats (like those in coconut oil) may behave differently than

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long-chain ones (like those in beef fat) inside our bodies. Moreover, the effects of different kinds of fatty acids on our health may also depend on our genetics, lifestyle, and health status. There are also some uncertainties about the nutritional impact of unsaturated fats. These fats may contain one double bond (monounsaturated) or multiple double bonds (polyunsaturated). Moreover, the double bonds may be in different positions within the fatty acid molecules, such as omega-3 or omega-6. The number and position of the double bonds, as well as the chain length of the fatty acids, impact their nutritional effects, and currently we only have a limited understanding of the health implications of these molecular differences. Thus, there are likely to be some nutritional consequences from changing the type of fats in our diet. Apart from losing the omega-3 fatty acids obtained from fatty fish, which are believed to have health benefits, there appears to be few adverse effects from switching to a more plant-based diet. Moreover, these kinds of healthy fatty acids can be obtained from some plant-derived sources. Both algal oil and flaxseed oil have high levels of omega-3 fatty acids, but the ones in algal oil more closely resemble those found in fish. This is not surprising because the fish get their omega-3 fatty acids by eating algae or plankton. Cholesterol People often assume consuming cholesterol is bad for their health. But it is essential for keeping us healthy because it plays several critical roles inside our bodies. It helps our immune and tissue repair systems function properly, and it acts as a template for the synthesis of vitamins, bile salts, and hormones [18, 19]. But having too much cholesterol in our bodies can cause health problems. There is some evidence that having high levels of specific types of cholesterol (small dense LDL) in our bloodstream increases our risk of heart disease [19, 20]. Consequently, adopting a diet that reduces our blood cholesterol levels could be beneficial to our health. It should be stressed that not all the cholesterol in our bodies comes from eating cholesterol-rich foods. Some of it is made inside us from other food components, such as fats and carbohydrates. Consequently, our blood cholesterol levels depend on our overall diet and not just the amounts of cholesterol-rich foods we eat. Switching to a plant-based diet may have some advantages for those with a high cholesterol level. The fats derived from plants contain less cholesterol than those from animals. Moreover, many plants contain high levels of phytosterols or phytostanols, which have chemical structures and biological functions like those of cholesterol. Consumption of foods containing these plant-based versions of cholesterol has been shown to reduce the cholesterol levels of humans [21]. The origin of this effect has been attributed to the

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ability of the p ­ hytosterols or phytostanols to interfere with the normal absorption of cholesterol from foods. Plant-based foods rich in these cholesterolreducing substances include vegetable oils, as well as certain fruits, vegetables, nuts, grains, and legumes [22].

Carbohydrates Meat and fish naturally contain relatively low levels of carbohydrates, whereas plants contain relatively high levels [23]. Consequently, there may be important nutritional implications from switching from animal- to plant-based foods caused by changes in the types and amounts of carbohydrates we consume. The most common carbohydrates in plants are sugars, starches, and dietary fibers, which each have different nutritional and health effects (Fig. 4.8). Sugars are small water-soluble molecules that provide sweetness to foods, as well as other beneficial features, such as generating desirable colors and flavors during cooking. Starches are natural polymers consisting of long chains of glucose molecules linked together like the pearls in a necklace. They are commonly used as ingredients in plant-based foods to provide desirable textural, binding, and fluid holding properties. Consuming foods containing high levels of sugars and starches is usually considered to be undesirable from a nutritional perspective because they have been linked to obesity, diabetes, and heart disease. Starches may be rapidly broken down by the digestive

Simple Sugars

Rapidly Absorbed

Starches

Digested and Absorbed

Dietary Fibers Not Digested

Amylose

Amylopectin

Fig. 4.8  Many kinds of carbohydrates are used to formulate plant-based foods. These carbohydrates are assembled from monosaccharides. The type, number, sequence, and bonding of the monosaccharides in a carbohydrate determine its nutritional and functional properties

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enzymes in our bodies to form glucose that is absorbed into our bloodstreams and causes “sugar” spikes. These spikes can cause us to overeat, as well as leading to problems with the way our bodies process glucose, resulting in insulin resistance and eventually diabetes. They can also cause us to experience a sugar crash, where we feel tired and have low energy. Regularly consuming sugary foods may also cause dental problems, such as tooth decay. Eating plant-based foods containing high levels of sugars and starches may therefore have undesirable health consequences. Some companies are using starches to formulate plant-based foods because they can give similar textural attributes to those normally provided by the proteins in meat and seafood products. Consumers should therefore carefully check the labels of plant-based foods to ensure the products do not contain unhealthy levels of sugars and starch. Many plants are rich sources of dietary fibers, which are a form of carbohydrate that cannot be digested or absorbed in the upper regions of our guts but may be fermented by the bacteria living in our colons. Unlike sugars and starches, consuming dietary fibers is good for us. Several health benefits have been linked to dietary fibers, including reducing constipation, cholesterol levels, and colon cancer. All dietary fibers, however, are not the same. They come from different parts of plants, have different chemical compositions, and have different molecular structures. As a result, they have different nutritional and health effects. However, we are only beginning to understand how specific kinds of dietary fibers impact our health. Once we have a better understanding, this knowledge could be used by food formulators to fortify plant-based foods with those dietary fibers known to improve our health. As mentioned earlier, meat and fish contain very low levels of dietary fibers and so switching to a fiber-rich plant-based diet could have some health benefits.

Micronutrients Micronutrients are dietary components essential to life, such as vitamins and minerals, which are normally found in relatively low levels in our foods. We must get enough of these substances from our diets to remain healthy. For this reason, governments typically stipulate a recommended daily amount (RDA) that people should consume to meet their nutritional requirements (Table 4.5). Different kinds of micronutrients are found in different kinds of foods. Most of the micronutrients we need can be obtained from plants, but there are some that are mainly obtained from animal-derived foods, such as meat, fish, milk, and eggs. Consequently, switching from an omnivore diet to a vegetarian or vegan one could have important nutritional consequences, unless a

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Table 4.5  Overview of the micronutrients (vitamins and minerals) that might be lacking in a vegetarian or vegan diet and their role in our nutrition and health Micronutrient Function

Source

Vitamin B12

Dairy products, eggs, meat, 2.4 μg seafood, fortified cereals, fortified plant-based foods

Vitamin D

Iron

Calcium

Zinc

Conversion of food into energy, nervous system function, red blood cell formation Blood pressure regulation, bone growth, calcium balance, hormone production, immune function, nervous system function

RDA

Eggs, fish, fish oil and cod 15 μg liver oil, pork, fortified dairy products, fortified margarine, fortified orange juice, fortified plant-based beverages, fortified breakfast cereals, mushrooms Meat, seafood, eggs, beans, 8–18 mg fruits, green vegetables, nuts, peas, seeds, tofu, whole grain

Energy production, growth and development, immune function, red blood cell formation, reproduction, wound healing Blood clotting, bone and Dairy products, canned 1000 mg teeth formation, seafood with bones, constriction and relaxation fortified orange juice, of blood vessels, hormone fortified plant-based secretion, muscle beverages, fortified contraction, nervous breakfast cereals green system function vegetables, tofu Growth and development, Meat, seafood, dairy 8–11 mg immune function, nervous products, beans, peas, nuts, system function, protein whole grains, formation, reproduction, fortified cereals taste and smell, wound healing

This information is adapted from the Vitamins and Minerals Chart of the USDA. Key: RDA is the recommended daily amount for adults (which depends on sex, age, and pregnancy status)

person takes special precautions to get enough of the micronutrients lacking in plant-based foods. Here, I explore some of the most important micronutrients that may be missing from a plant-based diet, discuss the potential health implications, and highlight where they can be obtained from non-animal sources.

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Iron Iron is critical for the proper functioning of hemoglobin and myoglobin within our bodies. These two proteins are responsible for carrying oxygen through our bloodstreams and muscles, which is essential for a healthy life. Iron is also required for the creation of some of the hormones needed to regulate the proper functioning of our bodies. In foods, iron is present in the form of heme or nonheme iron, which has important nutritional consequences. Meat and fish products contain high levels of heme iron, which is iron held inside hemoglobin or myoglobin. This form of iron tends to have a relatively high bioavailability because the heme proteins carry the iron into our guts and then release it when they are digested in our stomachs and small intestines. Many plant-derived foods, such as beans, legumes, dark leafy vegetables, dried fruits, nuts, seeds, whole grain breads, and fortified breakfast cereals, also contain high levels of iron. However, the iron in these foods is in a nonheme form, which has a relatively low bioavailability, meaning that only a small fraction of the amount consumed is actually absorbed and used by our bodies. The poor bioavailability of iron in plant-based foods is often because it is strongly bound to other food components that do not release it inside our guts, such as polyphenols. It is for this reason that the National Institutes of Health (NIH) in the United States recommends that those on a strictly plant-­ based diet eat twice as much iron as those who eat meat. To try to overcome this problem, food researchers are developing innovative ways of increasing the bioavailability of nonheme iron in plant-based foods, e.g., by removing the polyphenols or by encapsulating the iron within nanoparticles. These nanoparticles prevent the iron interacting with antinutrients and help to carry it to our gut walls where it can be absorbed. Some innovative food companies are using heme iron that does not come from animals. Leghemoglobin is a heme protein found in the roots of soybeans. Due to its structural similarity to hemoglobin and myoglobin, the iron in leghemoglobin would be expected to have a similar bioavailability to the iron found in meat or fish. Leghemoglobin is mainly used in the plant-based meat products developed by Impossible Foods because it produces the same desirable colors and flavors provided by the heme proteins in real meat. In practice, there is not enough leghemoglobin in the roots of soybeans to meet the huge demands of the plant-based food industry. Consequently, Impossible Foods has used genetic engineering and fermentation approaches to produce leghemoglobin using microbes rather than plants.

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Zinc Vegans and vegetarians may also be deficient in zinc because it mainly comes from animal-derived foods, like meat and seafood [24]. Several physiological processes that impact our health and wellbeing depend on zinc, including our growth and development, our immune and nervous systems, our ability to synthesize proteins, the ability of our bodies to heal wounds, our reproductive systems, and our sense of taste and smell. If we do not get enough zinc from our diets, there may therefore be many undesirable health consequences, like an increased risk of infection, stunted growth, skin problems, reproductive problems, and taste, smell, and sight disorders. Zinc is present in relatively high levels in some kinds of natural plant-derived foods, like peas, beans, nuts, and whole grains. However, its bioavailability is typically much lower from these sources than from animal ones. This is because plants often contain antinutrients like phytic acid and oxalates that strongly bind to the zinc and reduce its absorption by our bodies [25]. For this reason, vegans and vegetarians are often recommended to take zinc supplements or foods fortified with zinc [26], especially pregnant women [27]. The bioavailability of zinc can be improved using food processing technologies that remove or deactivate the antinutrients or by controlling the composition and structure of foods.

Calcium Calcium is required at much higher levels than other minerals in our diets because of its critical role in bone health [24]. However, calcium also plays important roles in other physiological processes within our bodies, such as those involved in making sure our muscles, nerves, blood vessels, hormones, and enzymes operate properly. A deficiency of calcium in our diets can lead to osteoporosis and an increased risk of bone fractures, as well as to other adverse health effects, such as numbness, tingling in the fingers, convulsions, and abnormal heart rhythms. In developed countries, the main source of calcium in the human diet is dairy products, including milk, yogurt, and cheese [28, 29]. Vegetarians who consume dairy products are therefore not at great risk of a calcium deficiency. However, vegans are at risk unless they take calcium supplements, eat calcium-fortified foods, or select foods that are naturally rich in calcium. Several kinds of natural plant-based foods do contain relatively high levels of calcium, including kale, broccoli, Brussel sprouts, collard greens, and grains. Moreover, many processed foods are fortified with calcium,

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including fruit juices, milk analogs, yogurt analogs, and breakfast cereals. As with zinc and iron, the bioavailability of calcium in plant-based sources is often relatively low because they contain antinutrients like phytic acid or oxalate that bind strongly to it and inhibit its absorption by our guts [30]. When designing plant-based foods it is therefore important to fortify them with a sufficiently high quantity of bioavailable calcium.

Vitamin B12 Vitamin B12 is a water-soluble substance that mainly comes from animal sources like meat, fish, eggs, and milk. Vegetarians who eat egg or dairy products, or pescatarians who eat fish, may therefore get enough of this vitamin in their diet. However, vegans who completely avoid all animal products may not get enough. Vitamin B12 is essential for keeping the nerve and blood cells in our bodies healthy, as well as for creating the genetic materials within our cells required to help us function [31]. A diet deficient in this micronutrient may therefore cause serious health problems. Vegetarians and vegans can avoid these problems by taking supplements or fortified foods. In this case, vitamin B12 can be derived from microbial sources, rather than from animal ones.

Vitamin D Vitamin D is an oil-soluble substance that is only found in a limited number of foods, which mainly come from animals. There are actually two major forms of this micronutrient: vitamin D2 and D3. Vitamin D3 is only present at significant levels in animal foods, such as meat, milk, and eggs. However, it can also be synthesized in our bodies when sunlight strikes our skin, but this source is limited in people who live in regions of the world with low sunlight or who are heavily protected by clothes or sunscreen. For this reason, people living in countries far from the equator are often recommended to take vitamin D supplements in autumn and winter when the sunlight levels are low. Many people in Scotland, where many of my family now live, suffer from low vitamin D levels because of the lack of sunlight there. Surprisingly, some people in hot sunny climates, like Saudi Arabia, may also suffer from vitamin D deficiency because they are often fully covered by clothing and so get little direct exposure to the sun. Vitamin D2 is typically obtained from plant-based sources, such as fungi, but these are usually scarce in most people’s diets.

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Moreover, the bioavailability of vitamin D may be relatively low from many natural sources and supplements because of its poor solubility in the gastrointestinal fluids inside our bodies. Many people following a purely plant-based diet may therefore be deficient in this essential micronutrient. A lack of vitamin D in the human diet can result in a range of health problems, including osteoporosis, weak bones, growth retardation, and muscle weakness. For this reason, vegetarians or vegans should consider taking a supplement or eating foods fortified with vitamin D.  The vitamin D2 used in supplements is always from non-animal sources, but the vitamin D3 may come from either animal or non-animal sources, and so one must be careful if one wants to strictly conform to a vegan or vegetarian diet. Scientists are developing innovative ways of fortifying plant-based foods with vitamin D to provide a good source of this essential micronutrient. Vitamin D is a very hydrophobic molecule, which means that it hates to be in water. In fact, if you tried to mix vitamin D with water, it would simply separate and form an oil slick on top, which makes it difficult to incorporate into many kinds of foods and drinks. In my research lab, we have used nanotechnology to increase the ability of vitamin D to be mixed into foods and drinks, as well as to enhance its bioavailability. We do this by trapping it inside tiny fat droplets, which are like those found in cow’s milk but made from plant-­ based ingredients. These vitamin-enriched fat droplets can then be incorporated into food products such as plant-based meat, seafood, egg, or dairy products. The bioavailability of the vitamin is increased because the fat droplets are rapidly digested by the enzymes in our guts. The digested fats then form tiny particles (“micelles”) that incorporate the vitamin D and transport it to the cells that line our gastrointestinal tracts where it can be absorbed.

Omega-3s Omega-3s are a type of healthy fat found in relatively high levels in certain kinds of fish, such as salmon, mackerel, or tuna. They may therefore be lacking in the diets of vegans or vegetarians who do not eat fish. Nutritional studies suggest that eating foods rich in omega-3s can have significant health benefits. For instance, consumption of foods rich in omega-3s has been linked to a reduced risk of heart disease, inflammation, immune disorders, and mental problems, as well as enhanced infant development [32]. Like most other fats in our diet, omega-3s come in the form of triglycerides consisting of three fatty acids attached to a glycerol. Omega-3s are part of the family of

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Fig. 4.9  Different kinds of omega-3 fatty acids are present in foods: eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid (ALA). These fats are often considered to be healthy

polyunsaturated fatty acids (PUFAs), which are often listed on food nutrition labels. What makes the omega-3s different from their close cousins the omega­6s is the position of the double bonds in the molecules. This small difference has a major impact on their biological activities and health benefits. Even within the omega-3 family, there are several members that exhibit different nutritional effects, including alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). These three molecules differ in the number of carbon atoms and double bonds they contain (Fig. 4.9). It is widely accepted that EPA and DHA are more beneficial to our health than ALA, which can be a challenge for vegetarians and vegans. Traditionally, EPA and DHA mainly came from fish, whereas ALA came from some plant species, such as flaxseed oil. ALA can be transformed into EPA and DHA inside our bodies, but this is not a very efficient process, and so it is better to consume EPA and DHA directly. To address this challenge, some food companies are cultivating microalgae, which naturally contain high levels of these healthy fats, in large fermentation vats. They then break open the microalgae cells and collect the oils released. Vegetarians and vegans can then get the beneficial omega-3s they need by taking supplements or foods fortified with these microalgae oils. One advantage of getting omega-3s from plants or algae is that there is less risk of getting mercury poisoning. Many fatty fish contain relatively high levels of this toxic substance because of the pollution of our oceans. This is why women are recommended not to eat certain kinds of fatty fish when they are pregnant.

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Due to their low levels in many vegan and vegetarian diets, there has been a great deal of interest in incorporating omega-3s from algae or flaxseed oils into plant-based foods. This is, however, often challenging because they are not soluble in water and they tend to go rancid, leading to a highly undesirable smell. As with vitamin D, our laboratory has been using nanotechnology to create more stable and bioavailable forms of omega-3s that can be easily incorporated into plant-based foods. We trap the omega-3s in tiny fat droplets that are coated by antioxidant proteins that stop them from going rancid.

Nutraceuticals Another important difference between animal- and plant-derived foods is the types and amounts of nutraceuticals they contain. Nutraceuticals are edible substances that are not essential for human health (like vitamins and minerals) but may still provide health benefits, like reducing the risk of heart disease, cancer, or diabetes. Foods derived from plants tend to have much higher levels of nutraceuticals than those derived from animals. A broad spectrum of nutraceuticals with different health effects are present in plant-based foods, including carotenoids (e.g., from carrots, tomatoes, pumpkins, peppers, and kale), curcumin (e.g., from turmeric), anthocyanins (e.g., from berries and red cabbage), and other types of polyphenols (e.g., from coffee and tea). Eating a diet rich in foods containing nutraceuticals has been linked to lower risks of various kinds of chronic disease, including cancer, heart disease, diabetes, stroke, brain disorders, and eye diseases [33]. In some cases, consuming nutraceuticals has been reported to increase human performance, like attention, mood, endurance, or energy levels. The origin of these effects is still not understood, and this is an active area of investigation. Researchers have proposed many physiological mechanisms to account for the health benefits of nutraceuticals. In general, these substances may improve our gut microbiomes, or they may be absorbed into our bodies and interact with key biochemical pathways associated with health and wellbeing. In particular, they have been reported to exhibit strong antioxidant, antimicrobial, anti-­ inflammatory, and anticancer effects. For instance, the curcumin in turmeric, which is widely used as a color and flavor in Indian foods, has been claimed to have anti-inflammatory effects, whereas the green tea drank in many Asian countries has been claimed to have antidiabetic effects. Even so, many of the health claims made for nutraceuticals still need to be verified in rigorous scientific studies [34].

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Table 4.6  Examples of several kinds of nutraceuticals found in plant-based foods and their potential health benefits Nutraceutical

Plant-based source

Claimed health benefits

Omega-3 fatty acids (DHA, EPA, ALA)

Algae oil, flaxseed oil

Carotenoids β-carotene, lycopene, lutein, zeaxanthin Curcumin

Carrots, kale, mangoes, peppers, spinach, tomatoes, watermelon, yams Turmeric

Reduced heart disease, inflammation, immune disorders, and mental disorders Pro-vitamin A activity, anticancer activity, improved eye health

Resveratrol

Grape seeds, wine, berries, peanuts, cocoa Coffee, tea, cocoa, fruit, berries, beans

Polyphenols

Phytosterols/ phytostanols

Fruits, legumes, nuts, seeds, vegetables, whole grains

Reduced cancer, diabetes, depression, obesity, pain, and stroke Reduced cancer, heart disease, diabetes, and brain disease Reduced cancer, inflammation, obesity, diabetes, heart disease, brain disease Reduction in cholesterol levels

Adapted from McClements [34]

Nutraceuticals may be found in natural foods (like fruits, vegetables, herbs, and spices) or they may be extracted from these natural sources and then used as ingredients in processed foods. In the latter case, the foods must be carefully designed so the nutraceuticals remain stable during storage and are then bioavailable after consumption. My research group has used a variety of food architecture and nanotechnology approaches to achieve these goals. In general, plant-based foods tend to contain a greater number and diversity of nutraceuticals than animal-based ones, and so have better health-­ promoting effects. Consequently, incorporating a greater number of plant-based foods into your diet may improve your health and wellbeing. Several kinds of nutraceuticals commonly found in plant-based foods are shown in Table  4.6, along with some of the health benefits claimed for them [34].

Digestibility and Bioavailability There are some differences in how plants and animal foods behave as they travel through our guts, which have important health implications. As mentioned earlier, our bodies do not naturally produce enzymes that can digest certain kinds of plant materials, which we refer to as dietary fibers. This

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includes things like cellulose, hemicellulose, and pectin, which are structure-­ forming polysaccharides that give plants their mechanical strength. These dietary fibers therefore pass through the upper regions of our guts and reach our colons intact. Our bodies cannot extract energy directly from these dietary fibers, which was a problem in prehistoric times when there were scarce resources in our environment. Now, however, this is seen as a benefit. First, there are so many calories readily available to us; it is good to eat foods that contain lots of dietary fibers because they are bulky and satisfying, but do not fill us with lots of calories, thereby helping to prevent us from becoming overweight. Second, dietary fibers help to hold water inside the foods in our guts, making them sloppier. As a result, the remnants of our foods move through our guts more easily, helping us to avoid constipation. Indeed, researchers have shown that vegetarians have faster moving and more copious poop than meat eaters. Finally, some dietary fibers may have health benefits, such as reducing colon cancer or heart disease. Thus, there appears to be many health benefits from eating plant-based foods that are rich in dietary fiber. In contrast, meat contains little or no dietary fiber and so cannot provide these desirable health effects. Meat tends to be fully digested inside the human gut, so all its nutrients are released and absorbed. In the distant past, this would have been a huge evolutionary advantage to our ancestors. But now, there are so many calorie- and nutrient-dense foods in our diet we don’t need any extra ones from meat. There are, however, some potentially negative aspects from getting our nutrients from plant-based foods. As mentioned earlier, some plants contain antinutrients, which interfere with the normal digestion or absorption of foods, thereby reducing the number of calories and nutrients we obtain from them. Some of the most important antinutrients found in plant-based foods are highlighted here: • Phytate: Phytate is naturally present in many seeds, grains, and legumes. It is a negatively charged substance that can strongly bind to positively charged minerals in our foods, such as iron, zinc, magnesium, and calcium. As a result, the absorption of the essential minerals by our bodies is reduced because the mineral-phytate complexes formed are too large to penetrate through our gut linings. • Tannins: Tannins are also found in many plant-based foods. They are part of a class of substances called polyphenols, which can strongly bind to the digestive enzymes in our guts and inactivate them, thereby reducing the digestion of fats, proteins, and carbs.

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• Lectins: Lectins are a type of protein found in plant-based foods, especially seeds, legumes, and grains, which may be harmful when consumed in high amounts because they interfere with nutrient absorption and promote gut inflammation. • Oxalates: Many vegetables (such as spinach) contain high levels of oxalates, which can strongly bind to calcium, thereby decreasing its absorption by our bodies. For most people living in developed countries these antinutrients are not a major issue since we have so many other sources of nutrients in our diets. However, they may be a problem for people living in developing countries with nutrient-deficient diets or for those who live exclusively on a narrow range of plant-based foods. The potentially adverse effects of these antinutrients are often reduced during normal food preparation procedures, such as soaking, washing, or cooking. Moreover, modern food processing operations can be designed to remove or deactivate antinutrients. The term bioavailability has come up a lot when discussing the nutritional differences between animal- and plant-based foods. It is therefore worthwhile to look at this important concept in a bit more detail. The bioavailability of a nutrient is the fraction that is absorbed by our bodies in a biologically active form. A food can contain high levels of a nutrient, but if it never gets absorbed by our bodies, then it cannot do us any good. There are big differences in the bioavailability of the nutrients in foods from animal and plant sources. As mentioned earlier, the heme iron in meat and seafood is much more bioavailable than the nonheme version in plant-based foods. This is because the hemoglobin and myoglobin in meat carry the iron into the stomach and small intestine and then release it when they are digested, so it can be rapidly absorbed. Plants often contain antinutrients that bind strongly to the iron and prevent it from being absorbed. Consequently, it is important to understand the different types of these antinutrients in different kinds of plant-­ based foods and either remove or deactivate them. The bioavailability of many other essential minerals, like calcium, magnesium, or zinc, may also be low in plant-based foods because of the presence of these antinutrients, which can be overcome using similar approaches. The bioavailability of some vitamins may also be less in plant sources than animal ones, due to differences in the cellular structures containing them [35]. Muscle foods are often completely digested in the gastrointestinal tract and release all the vitamins, whereas the tough fibrous structures in plants may not be fully digested and so they do not release them all (think of the nutrient-rich sweetcorn in your toilet bowl). Moreover, the proteins in plants

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are often less bioavailable than those found in meat because of differences in the way they are digested in the gastrointestinal tract. Overall, switching to a plant-based diet could reduce the amounts of proteins and micronutrients in our diet. However, recent advances in modern science and technology have made it possible to increase the bioavailability of many nutrients in plant-based foods. For instance, encapsulating vitamins or minerals in tiny particles created using nanotechnology has been shown to greatly increase their bioavailability [36, 37]. The application of these innovative technologies could lead to a new generation of healthier plant-based foods.

 re Vegetarians and Vegans Healthier than A Meat Eaters? There is a lot of evidence from epidemiology (observational) studies that vegetarians and vegans tend to be healthier than omnivores [38, 39]. This evidence comes from comparing the health of a group of people who don’t eat meat with another group who do eat meat, trying to keep all other variables equal. These studies show that vegetarians and vegans tend to have lower incidences of obesity, heart disease, high blood pressure, diabetes, metabolic syndrome, cancer, and arthritis than meat eaters. Moreover, there is some evidence that vegetarians and vegans live longer and have a higher quality of life in old age. The health benefits of a plant-based diet have been attributed to lower consumption of substances in animal products that negatively impact our health (such as saturated fat, cholesterol, and salt), as well a higher consumption of substances found in plants that positively impact our health (such as dietary fibers and nutraceuticals). We must be careful, however, when interpreting these studies because vegetarians and vegans by their very nature are more selective about what they eat. As a result, they may be more likely to choose healthier foods because they are already concerned about their diet, and may also be more likely to exercise, and less likely to smoke and drink excessive amounts of alcohol. But it is not all good news from a nutritional perspective for those who choose not to eat meat. Being a strict vegetarian or vegan may not always make you healthier. In their review of the advantages and disadvantages of vegetarian and vegan diets, a group of Italian scientists concluded “despite the popular opinion that vegetarianism and veganism are healthy options, there are some precautions to be taken to ensure that the diet is well balanced” [38]. As discussed already, meatless diets are often lacking in key essential nutrients,

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such as essential amino acids, omega-3 fatty acids, calcium, zinc, iron, vitamin B12, and vitamin D, that are normally obtained from animal sources like meat, fish, egg, or milk products. This is not surprising. Animals are made from the same kinds of cells as we are and so they contain all the basic building blocks we need. In contrast, plants are very different organisms to us and so do not have everything we need to keep our bodies functioning properly. Some studies have shown that vegan children tend to be shorter and thinner than their omnivore counterparts and in some extreme cases may suffer from severe malnutrition [38]. However, with a well-planned diet, often including supplements, potentially adverse nutritional effects can be avoided.

All Plant-Based Diets Are Not the Same As stated by Prof. Frank Hu, a nutritional scientist from Harvard University: “All Plant Foods are Not Created Equal” [40]. There are good meat-free diets and bad ones, just as there are healthy omnivore diets and unhealthy ones. Sugar is an example of a sustainable plant-based food, but if you only lived off sugary cookies and candies, your health (and teeth) would certainly deteriorate. I have met fat vegetarians and thin ones, rosy-faced ones, and pasty ones. Just as I have for meat eaters. Prof. Hu has categorized plant-based diets as healthy or unhealthy depending on their composition. Healthy diets contain whole grains, fruits, vegetables, nuts, legumes, vegetable oils, tea, and coffee. These foods contain high levels of dietary fiber, unsaturated fats, and nutraceuticals that may promote our health. In addition, they are usually less energy-dense and digested more slowly, which helps to prevent us from eating too much and stops disruption of our hormonal and digestive systems, which could eventually lead to diabetes and other diseases. Conversely, unhealthy plant-based diets contain high levels of refined starches, potatoes, fruit juices, sugary drinks, snacks, sweets, and desserts. These foods are often calorie-rich but nutrient-poor. They also contain high levels of saturated fats and sodium that are linked to heart disease and high blood pressure. Moreover, the starches in these foods are rapidly digested, which can lead to a spike in our blood sugar levels, which promotes overeating and diabetes. Healthy plant-based diets have been reported to reduce our risk of heart disease, obesity, diabetes, high blood pressure, and various other diseases, whereas unhealthy ones have the opposite effect. Overall, these nutritional studies suggest that a well-planned plant-based diet can be healthy but a poorly planned one can be unhealthy [40]. A healthy plant-based diet has

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been reported to be better for us than a traditional omnivore diet. Nutritional studies have shown that even modest decreases in the amount of meat (especially beef ) consumed can lead to significant improvements in health. If you are going to eat meat, Prof. Hu recommends that you eat fish or chicken, rather than beef or lamb, because they are healthier for you and the planet.

My Takeaway Unlike environmental and ethical reasons, which I strongly believe favor adopting a meat-less diet, I find the argument for not eating meat because of health reasons to be much less convincing. The healthiness of any diet, whether it contains meat or not, depends on the types and amounts of foods you eat. As concluded by Prof. Hu in one of his publications, a plant-based diet is not synonymous with a “healthy diet.” Eating only plant-based foods doesn’t necessarily make you healthier and may even make you sicker, if you do not get enough good quality proteins, vitamins, and minerals in your diet. However, it is certainly possible to have a healthy diet without eating meat. Reducing the levels of certain kinds of highly processed foods (those containing high levels of salt, fat, and sugar), as well as increasing the amounts of fruits, vegetables, legumes, beans, nuts, and whole grain cereals in your diet, will have health benefits. Recent research suggests that plant-based meat alternatives can be designed to be as healthy, if not healthier, than the real meat products they are intended to replace. Simply swapping a beef burger with a well-designed plant-based alternative may therefore have health benefits. I stopped eating meat nearly 8 years ago and have not noticed any changes in my health during this time. However, I am a college professor who has the resources to purchase healthy plant-based foods, which are often more expensive, difficult to access, and more time consuming to prepare than real meat products. I also take supplements every morning, including a multivitamin and vitamin B12, to avoid any potential micronutrient deficiencies. Some food companies are already fortifying their plant-based meat products with bioavailable forms of proteins, vitamins, and minerals that might be lacking in a vegetarian or vegan diet. Moreover, they are trying to make their products nutritionally equivalent or better than those of real meat. As more of these nutritionally optimized meat alternatives come onto the market, it will become less important to take supplements, which should facilitate the transition to a more sustainable diet that is also healthier for us. In this chapter, I mainly considered the potential health effects of replacing meat with plant-based alternatives because these are currently the most

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common meat substitutes on the market. There are different nutritional implications when meat is replaced with other forms of alternative protein foods, such as those obtained from insects, microbes, or cultured meat. These implications will be considered in later chapters.

References 1. Mann, N.J., A brief history of meat in the human diet and current health implications. Meat Science, 2018. 144: p. 169–179. 2. Hejnol, A. and J.M.  Martin-Duran, Getting to the bottom of anal evolution. Zoologischer Anzeiger, 2015. 256: p. 61–74. 3. Nielsen, C., T. Brunet, and D. Arendt, Evolution of the bilaterian mouth and anus. Nature Ecology & Evolution, 2018. 2(9): p. 1358–1376. 4. Watts, D.P., Meat eating by nonhuman primates: A review and synthesis. Journal of Human Evolution, 2020. 149. 5. Mann, N., Meat in the human diet: An anthropological perspective. Nutrition & Dietetics, 2007. 64: p. S102–S107. 6. Pontzer, H. and B.M. Wood, Effects of Evolution, Ecology, and Economy on Human Diet: Insights from Hunter-Gatherers and Other Small-Scale Societies. Annual Review of Nutrition, 2021. 41(1): p. 363–385. 7. Wrangham, R., Catching Fire: How Cooking Made Us Human. 2009, New York, NY: Basic Books. 8. Marinangeli, C.P.F., et al., The effect of increasing intakes of plant protein on the protein quality of Canadian diets. Applied Physiology, Nutrition, and Metabolism, 2021. 46(7): p. 771–780. 9. Magkos, F., et al., Perspective: A Perspective on the Transition to Plant-Based Diets: a Diet Change May Attenuate Climate Change, but Can It Also Attenuate Obesity and Chronic Disease Risk? Advances in Nutrition, 2020. 11(1): p. 1–9. 10. Tso, R. and C.G.  Forde, Unintended Consequences: Nutritional Impact and Potential Pitfalls of Switching from Animal- to Plant-Based Foods. Nutrients, 2021. 13(8): p. 2527. 11. Farsi, D.N., et al., The nutritional impact of replacing dietary meat with meat alternatives in the UK: a modelling analysis using nationally representative data. British Journal of Nutrition, 2022. 127(11): p. 1731–1741. 12. Gorissen, S.H.M., et al., Protein content and amino acid composition of commercially available plant-based protein isolates. Amino Acids, 2018. 50(12): p. 1685–1695. 13. Joye, I., Protein Digestibility of Cereal Products. Foods, 2019. 8(6). 14. Pinckaers, P.J., et al., The anabolic response to plant-based protein ingestion. Sports Medicine, 2021. 51(1): p. 59–74.

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15. Pinckaers, P.J.M., et al., The Anabolic Response to Plant-Based Protein Ingestion. Sports Med, 2021. 51(Suppl 1): p. 59–74. 16. Astrup, A., et  al., Dietary Saturated Fats and Health: Are the U.S.  Guidelines Evidence-Based? Nutrients, 2021. 13(10): p. 3305. 17. Bloise, A., et al., Cardiometabolic impacts of saturated fatty acids: are they all comparable? International Journal of Food Sciences and Nutrition, 2021. 18. Luo, J., H.Y. Yang, and B.L. Song, Mechanisms and regulation of cholesterol homeostasis. Nature Reviews Molecular Cell Biology, 2020. 21(4): p. 225–245. 19. Yu, X.H., et  al., Cholesterol transport system: An integrated cholesterol transport model involved in atherosclerosis. Progress in Lipid Research, 2019. 73: p. 65–91. 20. Mach, F., et al., 2019 ESC/EAS Guidelines for the management of dyslipidaemias: lipid modification to reduce cardiovascular risk The Task Force for the management of dyslipidaemias of the European Society of Cardiology (ESC) and European Atherosclerosis Society (EAS). European Heart Journal, 2020. 41(1): p. 111–188. 21. Ghaedi, E., et  al., Phytosterol Supplementation Could Improve Atherogenic and Anti-Atherogenic Apolipoproteins: A Systematic Review and Dose-Response Meta-­ Analysis of Randomized Controlled Trials. Journal of the American College of Nutrition, 2020. 39(1): p. 82–92. 22. Moreau, R.A., B.D.  Whitaker, and K.B.  Hicks, Phytosterols, phytostanols, and their conjugates in foods: structural diversity, quantitative analysis, and health-­ promoting uses. Progress in Lipid Research, 2002. 41(6): p. 457–500. 23. Mattila, P., et  al., Nutritional Value of Commercial Protein-Rich Plant Products. Plant Foods for Human Nutrition, 2018. 73(2): p. 108–115. 24. Grungreiff, K., T. Gottstein, and D. Reinhold, Zinc Deficiency-An Independent Risk Factor in the Pathogenesis of Haemorrhagic Stroke? Nutrients, 2020. 12(11). 25. Rousseau, S., et al., Barriers impairing mineral bioaccessibility and bioavailability in plant-based foods and the perspectives for food processing. Critical Reviews in Food Science and Nutrition, 2020. 60(5): p. 826–843. 26. Bakaloudi, D.R., et al., Intake and adequacy of the vegan diet. A systematic review of the evidence. Clinical Nutrition, 2021. 40(5): p. 3503–3521. 27. Sebastiani, G., et al., The Effects of Vegetarian and Vegan Diet during Pregnancy on the Health of Mothers and Offspring. Nutrients, 2019. 11(3). 28. Gao, X., et al., Meeting adequate intake for dietary calcium without dairy foods in adolescents aged 9 to 18 years (National Health and Nutrition Examination Survey 2001–2002). Journal of the American Dietetic Association, 2006. 106(11): p. 1759–1765. 29. Romanchik-Cerpovicz, J.E. and R.J. McKemie, Research and professional briefs – Fortification of all-purpose wheat-flour tortillas with calcium lactate, calcium carbonate, or calcium citrate is acceptable. Journal of the American Dietetic Association, 2007. 107(3): p. 506–509. 30. White, P.J. and M.R. Broadley, Biofortifying crops with essential mineral elements. Trends in Plant Science, 2005. 10(12): p. 586–593.

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31. Rizzo, G., et  al., Vitamin B12 among Vegetarians: Status, Assessment and Supplementation. Nutrients, 2016. 8(12). 32. Tur, J.A., et al., Dietary sources of omega 3 fatty acids: public health risks and benefits. British Journal of Nutrition, 2012. 107: p. S23–S52. 33. Gul, K., A.K.  Singh, and R.  Jabeen, Nutraceuticals and Functional Foods: The Foods for the Future World. Critical Reviews in Food Science and Nutrition, 2016. 56(16): p. 2617–2627. 34. McClements, D.J., Future Foods: How Modern Science is Transforming the Way we Eat. 2019, New York, NY: Springer. 35. Schweiggert, R.M. and R. Carle, Carotenoid deposition in plant and animal foods and its impact on bioavailability. Critical Reviews in Food Science and Nutrition, 2017. 57(9): p. 1807–1830. 36. Tan, Y.B. and D.J. McClements, Improving the bioavailability of oil-soluble vitamins by optimizing food matrix effects: A review. Food Chemistry, 2021. 348. 37. Gharibzahedi, S.M.T. and S.M. Jafari, The importance of minerals in human nutrition: Bioavailability, food fortification, processing effects and nanoencapsulation. Trends in Food Science & Technology, 2017. 62: p. 119–132. 38. Petti, A., et al., Vegetarianism and veganism: not only benefits but also gaps. A review. Progress in Nutrition, 2017. 19(3): p. 229–242. 39. Sabate, J. and M. Wien, A perspective on vegetarian dietary patterns and risk of metabolic syndrome. British Journal of Nutrition, 2015. 113: p. S136–S143. 40. Hemler, E.C. and F.B. Hu, Plant-Based Diets for Cardiovascular Disease Prevention: All Plant Foods Are Not Created Equal. Current Atherosclerosis Reports, 2019. 21(5). 41. McClements, D.J. and L. Grossmann, The science of plant-based foods: Constructing next-generation meat, fish, milk, and egg analogs. Comprehensive Reviews in Food Science and Food Safety, 2021. 20(4): p. 4049–4100.

5 Staying Alive: Is a Meat-Free Diet Safer?

Abstract  There are differences in the safety risks associated with omnivore and meat-free diets. These differences may come from a variety of sources. There are differences in the types and levels of food contamination by harmful microorganisms (like bacteria, molds, viruses) and chemical toxins (like pesticides, fertilizers, heavy metals) for meat and meat alternatives. The use of antibiotics to treat animals in the livestock industry is raising the risk of antibiotic resistance, which means many of the drugs that we now use to treat common diseases may be ineffective in the future. There are allergy risks from introducing new sources of proteins into the human diet, such as those from unusual plant sources, insects, or microfungi. Raising animals for food increases the risk of global pandemics, like the coronavirus, which could have devasting health consequences. Consequently, it is important to carefully assess the risks and benefits from switching from an omnivore to a meat-­ free diet. Keywords  Foodborne illness • Coronavirus • Zoonotic diseases • Antibiotic resistance • Toxins • Allergies First, do not harm. Hippocrates

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 D. J. McClements, Meat Less: The Next Food Revolution, Copernicus Books, https://doi.org/10.1007/978-3-031-23961-8_5

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Keeping Our Foods Safe In the last chapter, I explored the impact of nutritional differences between diets with or without meat on our health. These differences typically only have a noticeable impact over long periods, often decades. Eating a bad diet throughout your early life increases your risk of chronic diseases when you get older. Foods also contain substances that can make us sick or kill us fairly quickly, such as chemical toxins or pathogenic microorganisms (Fig.  5.1). Moreover, the type of foods we eat impacts the risk of other kinds of serious illnesses, like those brought on by global pandemics or antibiotic resistance. It is therefore important to consider the food safety implications of switching from an omnivore to a vegetarian or vegan diet. We all have to eat every day to stay healthy. So, what is the risk of becoming sick or dying from simply putting foods in our mouths? In the United States, the Centers for Disease Control and Prevention (CDC) estimates around 48  million people get sick (around 1  in 6 of the population), 128,000 are hospitalized, and 3000 die from foodborne diseases every year [1]. There is also a large economic burden linked to these diseases, with estimates ranging from between $30 to $160  billion per year [2]. However, considering the enormous number of meals consumed every day, the personal risk of getting food poisoning is actually quite low per meal. For instance, in the United States, there are around 400 billion meals consumed each year, so the risk of

Fig. 5.1  Escherichia coli seen under a scanning electron micrograph. This type of bacteria is commonly found on meat and other food products. Each microbe is only a few micrometers big and so is much too small to see with the unaided human eye. (Image from the National Institute of Allergy and Infectious Diseases, National Institutes of Health (open access))

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actually dying from a particular meal is less than one-in-a-hundred million, which is about the same risk as crossing the road. Over your lifetime, the risk of dying from food poisoning is around 1-in-1500. According to the National Safety Council, this is less than drowning or dying in a fire, but more than choking on food. The modern food industry has been extraordinarily successful at reducing the risk of death and illness from what we eat. It is therefore important that any drastic changes we make to our food supply do not compromise our safety. Better still, if we can decrease the risk of death and illness by eating less meat, this would be an added advantage of switching to a meat-­ less diet.

The Good Old Days Food purists sometimes long for the “good old days” when our food was more wholesome, natural, and healthier, before the food industry created ultraprocessed foods that are slowly killing us by making us fat and unhealthy. But there were never any good old days. In fact, our food is much safer now than it has ever been, which is mainly because of the great efforts governments have taken to regulate the food and agricultural industries (see next section). As an example, death and disease due to consumption of non-pasteurized milk were common in the United States before 1900 [3]. These illnesses were caused by contamination of the milk with germs that cause foodborne diseases, like typhoid fever, botulism, scarlet fever, tuberculosis, anthrax, and foot and mouth disease. In 1906, Upton Sinclair published his famous novel The Jungle which graphically described the highly unsanitary conditions that food was produced in Chicago’s meat-packing district. Partly in response to the public’s increased awareness of food safety issues brought about by this book, the government introduced the Pure Food and Drug Act, which introduced measures such as handwashing, sanitation, refrigeration, and pasteurization. These measures led to major improvements in food safety. For instance, after widespread pasteurization of milk was introduced in the early 1900s, the incidences of diseases such as typhoid declined steeply (Fig. 5.2). This is because most harmful germs are killed when milk is heated above a certain temperature for a sufficient time (62.8 °C or 145 F for 30 min). The development of these preservation methods was particularly important for animal-derived products because they are full of the nutrients that germs need to survive and grow. This is one of the reasons we have to be extremely careful when handling raw meat and fish – they can contain harmful microbes that get onto our hands and into our mouths.

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Incidences of Typhoid

100 80 60 40 20 0 1900

1910

1920

1930

Year

1940

1950

1960

Fig. 5.2  The CDC estimates that the incidences of typhoid per 100,000 people decreased steeply after food safety initiatives, like pasteurization, were introduced in the early 1900s

Many of the traditional methods used to prepare foods, including cooking, salting, smoking, drying, and fermentation, were originally developed to improve food safety, as well as to preserve them. These are early examples of food processing, which are now so well established we do not even think of them as processing. Since then, scientists and regulators have developed much more sophisticated ways of ensuring our foods are safe, ranging from stipulating best practices to follow in farms, storage facilities, and factories, developing advanced forensic tools to detect contamination, and creating innovative ways of removing or killing any harmful microbes that contaminate our foods.

Food Regulations Dr. Diarrhea (a made-up name) is sitting in his office at the CDC on a warm summer day when he receives an urgent call. Numerous cases of illness have been reported in California, where people are reporting similar symptoms, including vomiting, diarrhea, fever, and stomach cramps. He knows these symptoms are typical of a foodborne illness, and so he gathers a team of scientists to establish the nature of the disease, what caused it, and how to prevent it from spreading. A foodborne outbreak occurs when two or more

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people become infected by the same harmful agent, which may be a microbe or a chemical toxin, and it is traced back to the same food source, such as a particular farm, factory, storage facility, or restaurant. These outbreaks are usually unintentional but may be caused by negligence or cost-cutting measures, such as not cleaning, handling, or cooking foods properly or not sanitizing factories or kitchens sufficiently. In other cases, they may just be bad luck – there are bacteria, viruses, and toxins all around us, and it is inevitable that they will sometimes get into our foods, even with the strictest food protection measures. Usually, the best we can do is to minimize the risk to an acceptable level. In the worst-case scenario, a foodborne outbreak could be an attack by domestic or foreign terrorists out to do us harm. In this case, we want to know what the harmful substance is and how we can minimize its impact. The discovery of a foodborne disease outbreak may lead to a food recall so as to mitigate its impact, although this can cause large economic damage to the companies involved, and so must be managed carefully. It is worth noting that the majority of foodborne outbreaks actually go undetected – people may get sick but never report it or the cause of their illness may never be identified. Safety concerns were one of the main reasons that laws were first introduced to regulate our foods. Some of the earliest laws governing food adulteration were passed in England by King John in the early thirteenth century. Similar laws were passed in New England in the seventeenth and eighteenth centuries. In 1862, Abraham Lincoln established the United States Department of Agriculture (USDA) and appointed a chemist to run the department responsible for testing food safety, which became the Food and Drug Administration (FDA) in 1906. In response to persistent and widespread food safety problems, a series of additional laws have been passed since then to regulate the way our foods are produced, handled, and sold. These regulations are usually a compromise between keeping us safe and ensuring foods can be produced economically on a large scale. Consequently, they are never perfect and evolve as we learn more about what causes food safety issues, and we develop new technologies to detect, remove, and deactivate harmful substances. Both animal- and plant-based foods are covered by strict regulations to ensure they are safe. Even so, there are differences in the safety risks associated with these different food categories.

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Which Is Safer: Animal- or Plant-Based Foods? In the summer of 2022, Consumer Reports did a survey of microbial contamination on meat products purchased from a supermarket [4]. Of the 351 packages of ground meat they tested, they found dangerous bacteria (Salmonella) in almost a third of the chicken products, as well as high levels in beef, pork, and turkey products. They detected a strain of pathogenic E. coli on one of the ground beef products that was present at such a dangerously high level that they alerted the USDA, which triggered a recall of over 28,000 pounds (12,700 kg) of the product from grocery stores. Ground meat is particularly susceptible to microbial contamination because the flesh of many different animals is combined, so if one of the animals is contaminated the whole batch is. The USDA requires meat producers to test for different kinds of microbes that may contaminate their products. However, this does not mean they are free from contamination. In the case of chicken, the product can still be sold if less than 10% of whole birds or 25% of ground meat from the birds is contaminated with Salmonella. Consequently, it is important for consumers to always assume these products are contaminated, to handle them carefully to avoid cross-contamination, and to thoroughly cook them. One of the important roles the CDC plays in the United States is to monitor the number of foodborne illness outbreaks for different kinds of microbes and food categories each year. A network of national laboratories, called PulseNet, uses DNA fingerprints of bacteria that make people sick to detect foodborne disease outbreaks. Information about these outbreaks is reported in the Foodborne Disease Outbreak Surveillance System (FDOSS), which is an online database accessible to the public. It is therefore possible to judge the relative risk of eating animal-derived foods (such as meat, seafood, dairy, and eggs) and plant-derived ones (such as fruit, vegetables, cereals, fungi, nuts, and seeds) on getting sick [5]. At the time of writing, the latest data available was for 2017. The report for that year indicated there were around 840 confirmed foodborne disease outbreaks in the United States, which resulted in around 14,000 illnesses, 827 hospitalizations, and 20 deaths. (These numbers are considerably lower than the ones given earlier because they only include cases that were actually reported to the authorities – the CDC estimates that the actual number of deaths and illnesses is much larger than these reported numbers.) Norovirus was the most common germ responsible for foodborne diseases, accounting for around 35% of the outbreaks and 46% of the reported illnesses, followed by Salmonella which accounted for around 29% of the outbreaks and 34% of the illnesses. Other common germs causing foodborne

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illnesses were Escherichia coli and Clostridium perfringens. My colleague Professor Matthew Moore at the University of Massachusetts is one of the world’s experts in noroviruses. When we go out for a pint of beer together, our conversations almost always gloriously descend to diarrhea. Matt talks passionately about his latest research findings on the development of new methods of isolating norovirus from poop, or new ways he can kill it. The most common foods associated with these outbreaks were marine and land animals (Fig. 5.3), with mollusks (19%), fish (17%), chicken (11%), and beef (9%) being the top four culprits. However, different microbes cause different degrees of illness. Consumption of contaminated land animals was the most common cause of illnesses associated with these food outbreaks, including turkeys (16%), chickens (13%), and pork (10%). However, fruit consumption (14%) also made an appreciable contribution. When looking at the data, I was surprised to learn that hospitalizations due to foodborne illnesses were much greater for plant-derived foods (55%) than for animal-derived ones (31%). The most likely reason for this is that many fruits are consumed raw (Fig. 5.4) and so do not undergo a heating step that would kill any harmful microbes on them. For this reason, it is always a good idea to wash your fruit before eating it. In contrast, most meat, seafood, egg, and dairy products 2500 Outbreaks

Illnesses

Hospitalizations

Number of Cases

2000

1500

1000

500

0

Aquatic animals

Land animals

Plants

Food Source

Fig. 5.3  Foodborne disease outbreaks and associated illnesses by food category in the United States in 2017. (Data from the Foodborne Disease Outbreak Surveillance System, CDC)

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Number of Hospitalizations

140 120 100 80 60 40 20 0

Root Veg Grains & Sprouts Beans

Herbs

Nuts & Leafy Veg Seeds

Fruits

Plant-based Food

Fig. 5.4  The number of hospitalizations due to foodborne disease outbreaks linked to eating plant-based foods. These incidences are mostly due to plant-based foods that are eaten raw, like leafy greens and fruits, because the microbes are not killed by cooking

undergo some form of heat treatment before they are consumed, such as cooking or pasteurization. In this case, the diseases arise because of poor handling of the food leading to contamination, or because the foods are not cooked properly. Many of the foodborne illnesses associated with plant-derived foods, such as fruits and vegetables, result from them coming into contact with animals or their waste products on farms, since agricultural crops and livestock animals are often raised on the same land. For example, pathogenic E. coli found on salad has been linked to contamination by the fecal matter in manure produced by livestock animals [6]. Consequently, reducing the number of animals on farms could also reduce the likelihood of getting food poisoning from raw fruits and vegetables.

The Severity of Illness All foodborne illnesses are not the same; some of them may make you mildly ill for a few hours or days, whereas others may hospitalize or even kill you (Table 5.1). Consequently, it is not only the number of people that get sick that is important, but also the seriousness of the illness. As mentioned earlier, there are differences in the nature and severity of the illnesses resulting from

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Table 5.1  Symptoms and sources of some of the most common germs responsible for food poisoning in the United States (CDC)

Germ

Symptoms

Salmonella

Symptoms begin 6 h to 6 days after exposure: diarrhea, fever, stomach cramps, vomiting

Foods commonly associated with the pathogen

Deaths (%)

28.0 Raw or undercooked chicken, turkey, and meat; eggs; unpasteurized (raw) milk and juice; raw fruits and vegetables Soft cheeses, raw sprouts, 18.9 melons, hot dogs, pâtés, deli meats, smoked seafood, and raw (unpasteurized) milk

Symptoms begin 1–4 weeks after exposure: pregnant women usually have a fever and other flu-like symptoms, such as fatigue and muscle aches. Infections during pregnancy can lead to serious illness or even death in newborns. Other people (most often older adults): headache, stiff neck, confusion, loss of balance, and convulsions in addition to fever and muscle aches Norovirus Symptoms begin 12–48 h after Leafy greens, fresh fruits, shellfish (such as exposure: diarrhea, nausea/ oysters), or unsafe stomach pain, vomiting water Campylobacter Symptoms begin 2–5 days after Raw or undercooked poultry, raw exposure: diarrhea (often (unpasteurized) milk, bloody), stomach cramps/ and contaminated pain, fever water Raw or undercooked Vibrio Symptoms begin 2–48 h after shellfish, particularly exposure: watery diarrhea, oysters nausea, stomach cramps, vomiting, fever, chills Beef or poultry, especially Clostridium Symptoms begin 6–24 h after large roasts; gravies; perfringens exposure: diarrhea, stomach dried or precooked cramps. Usually begins foods suddenly and lasts for less than 24 h. Vomiting and fever are not common Listeria

11.0

5.6

3.6

1.9

(continued)

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Table 5.1 (continued)

Germ

Symptoms

Foods commonly associated with the pathogen

Symptoms begin 3–4 days after Raw or undercooked ground beef, raw exposure: severe stomach (unpasteurized) milk cramps, diarrhea (often and juice, raw bloody), and vomiting. vegetables (such as Around 5–10% of people lettuce), raw sprouts, diagnosed with E. coli unsafe water develop a life-threatening health problem Symptoms begin 18–36 h after Improperly canned or Clostridium fermented foods, exposure: double or blurred botulinum usually homemade vision, drooping eyelids, (botulism) slurred speech. Difficulty swallowing and breathing, dry mouth. Muscle weakness and paralysis. Symptoms start in the head and move down as the illness gets worse Staphylococcus Symptoms begin 30 min to 8 h Foods that are not cooked after handling, aureus after exposure: nausea, such as sliced meats, vomiting, stomach cramps. puddings, pastries, and Most people also have sandwiches diarrhea E. coli (Escherichia coli)

Deaths (%) 1.5

0.67

0.44

Link: https://www.cdc.gov/foodsafety/symptoms.html#symptoms. The percentage of deaths due to foodborne illness was from “Foodborne Illness Acquired in the United States-Major Pathogens” [7]

eating contaminated animal- or plant-based products. Different kinds of microbes are present on different kinds of foods, which is mainly because each microbe has its own environmental and nutritional niche, just like animals do. A polar bear is unlikely to survive in the tropics, just as a cockatoo is unlikely to survive in the Antarctic. However, if you do encounter a polar bear, it is more likely to pose a health risk than a cockatoo. Some of the most common germs that cause food poisoning are shown in Table 5.1, along with the symptoms they cause and the kinds of foods commonly associated with their transmission. Many of the major causes of death resulting from foodborne illness arise from animal-derived foods, especially when they are raw or undercooked. Salmonella outbreaks are mainly caused by meat, eggs, and milk, Campylobacter outbreaks by poultry and milk, and Vibrio outbreaks by seafood. However, the severity of the outcome is often much greater for plant-­ derived foods, especially fruits and leafy greens (like read-to-eat salads), because they are not cooked. For this reason, the risk of getting very sick due

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to foodborne pathogens is worse for some plant-derived foods than animal-­ derived ones. Consequently, transitioning to a plant-based diet could have some drawbacks by increasing the overall number of deaths caused by foodborne illnesses. This problem may be partly mitigated if we consumed less meat, because then there would be less cross-contamination of plant-derived foods with pathogens from farm animals (such as the E. coli or Salmonella in manure). Even so, it is extremely important to handle and prepare plant-­ based foods carefully to avoid or reduce contamination with harmful germs, especially when they are going to be eaten raw. In particular, it is important to carefully wash raw fruits and vegetables with lukewarm water before eating them. The FDA recommends the following rather elaborate procedure when preparing raw fruits and vegetables for consumption: Before eating or preparing, wash fresh produce under cold running tap water to remove any lingering dirt. This reduces bacteria that may be present. If there is a firm surface, such as on apples or potatoes, the surface can be scrubbed with a brush. Consumers should not wash fruits and vegetables with detergent or soap [because] you could ingest residues. When preparing fruits and vegetables, cut away any damaged or bruised areas because bacteria that cause illness can thrive in those places. Immediately refrigerate any fresh-cut items such as salad or fruit for best quality and food safety.

It is also important to put the risk into perspective. As mentioned earlier, the CDC estimates that around 3000 people die from foodborne illnesses per year. This is much lower than the 415,000 people who died from COVID-19 in 2021. Moreover, we are not comparing apples with apples. The meat and seafood analogs designed to replace real meat and seafood have usually been thermally processed prior to sale, and most of them are cooked before eating. Consequently, there should be much less health risks associated with consuming these foods than raw fruits and vegetables.

Drugs and Chemicals The modern food supply relies on the use of many kinds of drugs and other chemicals to improve yields and reduce losses [8]. Fertilizers and pesticides are commonly applied to agricultural crops, whereas vaccines, antibiotics, and hormones are frequently given to animals. Some of these substances may have deleterious effects on human health, either in the short term (acute) or after

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prolonged exposure (chronic). Consequently, it is important they do not end up in our foods at levels that could cause us harm. Small amounts of pesticides and fertilizers inevitably remain on agricultural crops, such as cereals, fruits, and vegetables, because they may penetrate the plant tissues or stick to their surfaces. If pesticides and fertilizers are used correctly, these levels are quite low and are not considered to be a major health risk [9]. However, this is not always the case and so it is a good idea to wash these products prior to consuming them. The livestock industry commonly uses vaccines and hormones to ensure animals remain healthy throughout their lifespan, as well as to promote their rapid growth and so produce meat more quickly. Studies have shown that antibiotics and hormones given to livestock animals can end up in their manure, which then contaminates the soil and water used for growing agricultural crops [10]. They may also find their way into animal-derived foods, like meat, egg, and dairy products, which can promote allergic reactions, microbiome changes, and chronic illnesses in the people who eat them [9, 11]. Permissible levels of veterinary drug residues in animal-derived foods are strictly regulated and monitored in many countries, especially developed ones. Typically, most samples analyzed have residues below the legal limits and so should cause few health concerns [12]. However, a small fraction of food samples tested (usually less than 1%) do have veterinary drug residues exceeding these levels [11]. Given the huge number of livestock animals used as human foods every year, even 1% corresponds to an appreciable level of contaminated food products. It is therefore important for us to carefully control and test the levels of drugs and chemicals used in both animal- and plant-­ derived foods to ensure they are safe. Most of the agricultural crops we currently grow are fed to livestock animals. Consequently, reducing the amount of meat we eat would reduce the overall level of these contaminants in our environment and in our foods by reducing the total amounts of pesticides and fertilizers we need. Moreover, it would also decrease the amounts of hormones, vaccines, and antibiotics because these drugs would no longer need to be administered to livestock animals.

The Rise of Superbugs: Antimicrobial Resistance Imagine a time when many of our existing antibiotics no longer work. Diseases that used to cause large numbers of deaths every year, but are now easily treatable, may become deadly killers again, like pneumonia, tuberculosis, and gonorrhea. This is not something that is going to happen in the distant future, it

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is already happening now. The National Institutes of Health reports that more than 2 million people already become infected with antibiotic-resistant bacteria every year, and at least 23,000 people die due to these infections [13]. Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, who has played a major role in tackling both the HIV and COVID pandemics, has sounded the alarm on this issue. One of his biggest concerns was that people could go to hospitals for simple surgical operations and end up getting infected by an antimicrobially resistant bacteria from another patient, which could lead to severe illness or even death. The CDC reported that there was a large increase in deaths related to antimicrobially resistant bacteria during the first year of the COVID-19 pandemic, which was mainly related to the increased use of antibiotics to treat patients suffering from coronavirus infections [14]. The World Health Organization has also stated that increasing antibiotic resistance is one of the greatest threats to global health, economic development, and food security. Consequently, anything we can do to reduce it would be highly desirable. The misuse of antimicrobial drugs in the livestock industry is making this situation worse. It has been estimated that around 70–80% of all antibiotics are currently used by the livestock industry (Fig. 5.5). The rise of antimicrobial resistance due to the overuse of veterinary drugs (especially antibiotics) to treat livestock animals is one of the most urgent health risks associated with meat eating [9]. When we treat these animals with low levels of antibiotics over prolonged periods, the microbes that infect them evolve. Most of the Other

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Fig. 5.5  In 2018, the sales of medically important antibiotics were higher in livestock animals than in humans, which is raising concerns about the increase in antibiotic resistance

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microbes in an animal are usually killed after an antibiotic treatment, but a small fraction survives. These microbes and their decedents have some resistance to the antibiotics used. Over several generations, these microbes become immune to the current generation of antibiotics, thereby reducing our ability to treat diseases that may also harm humans, as well as reducing their efficacy in the livestock industry. Many of the diseases that can now easily be treated by prescribing antibiotics may become deadly. The National Institutes of Health has identified several germs that have already developed antimicrobial resistance and may lead to serious health problems in the future, including pneumonia, tuberculosis, salmonellosis, and gonorrhea. The Consumer Reports study mentioned earlier found that antibiotic-­ resistant bacteria were present in many of the meat products they bought from the supermarket [4]. Over 30% of the samples of ground chicken they tested were found to contain Salmonella. Of these, 100% were resistant to at least one antibiotic and 78% were resistant to multiple antibiotics. The same study found antibiotic-resistant bacteria in a significant number of the ground beef, pork, and turkey samples. One of the strains of Salmonella found in ground pork was resistant to 12 antibiotics. These findings are highly troublesome for people who eat meat for several reasons. First, it means they might get sick if they do not handle or cook the meat properly. Second, it means that if they do get sick, they may not be able to be treated properly for the infection using conventional antibiotics, thereby increasing their risk of hospitalization and death. Third, some types of Salmonella could transfer their resistant genes to other bacteria living in our guts, making them resistant too. The rise of superbugs in meat products is because antibiotics have been misused by the livestock industry. Instead of only using them to treat animals when they become sick, they have been using them at low doses throughout long periods of the animal’s life as prophylactics to stop them from becoming sick. As a result, the bacteria who infect livestock animals have the ideal conditions to evolve resistance to the antibiotics. Some of these antibiotics are the same ones used to treat human illnesses. Concerns about the growing problems with antimicrobial resistance have led some livestock producers to reduce the levels they use during the raising of farm animals, which will help to alleviate this problem. But not all livestock producers are doing this. The FDA has developed a 5-year plan to try to tackle this problem and reduce the level of antibiotics employed by the livestock industry. Evidence from Europe shows that countries that have introduced legal limits on the use of antibiotics to prevent diseases in livestock have seen a steep drop in their use [15]. This shows that it is possible to address this problem, provided governments are willing to act. Even so, the crowded and dirty conditions under which many

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livestock animals are raised still provide fertile breeding grounds for bacteria to multiply and mutate, which means that antimicrobial resistance will continue to increase because these sick animals still need to be treated with antibiotics. Some high value fruits and vegetables have been treated with antibiotics to tackle infections from certain kinds of bacteria, but this is very rare, accounting for less than 0.5% of total antibiotic use [16]. Thus, switching to a more plant-based diet could have large benefits to human health by reducing the total amounts of antibiotics used and thereby decreasing the likelihood of harmful bacteria becoming resistant to the drugs we need to treat them.

The Shock of the New: Allergies Many people experience allergic reactions when exposed to certain kinds of food ingredients (usually proteins), which may vary from mild to severe [17, 18]. In some cases, allergic reactions are so severe they lead to anaphylactic shock and even death. Typically, an individual is only sensitive to a specific kind of food protein (or closely related ones). The FDA reports that the main allergens in the United States are from milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, and soybeans. These foods account for around 90% of all food allergies reported in the United States. As can be seen, both animal- and plant-derived products are major sources of allergens. It should be stressed that several other kinds of foods can also trigger allergic reactions in some people. I have a friend who only has allergies to sunflower seeds. If you know the kinds of foods that give you allergies, then you can avoid them. If you are susceptible to a food allergy associated with milk, eggs, or seafood, then eating plant-based analogs of these products could help you enjoy these foods without having an allergic reaction. However, new allergen concerns may arise if meat, seafood, egg, and milk analogs are created using proteins that have not been common in the human diet before, such as those from insects or unusual plants [19, 20]. People who are allergic to proteins in one kind of food may be more sensitive to proteins in closely related foods. For instance, people with soy or peanut allergies should be careful when consuming pulse proteins, whereas people with wheat allergies should be careful eating barley or rye proteins. It is not obvious by simply looking at a meat or seafood analog to know what kinds of proteins it contains. So, people with concerns about allergies should always carefully check the label before eating these novel foods [21]. As new proteins are introduced into the food supply, and people become more exposed to them, new allergies may arise. For instance, after lupine

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proteins were introduced into the market in the 1990s, there was an appreciable increase in the number of people who became allergic to them [22]. A similar story occurred when soy proteins first began to be widely consumed in many Western countries. It is therefore likely that some people will exhibit allergies to some of the new proteins being used to formulate meat alternatives. Many of the cases reported as food allergies are actually caused by other issues, known as non-immune-mediated food intolerances [23]. A true allergic reaction is caused when a protein or a fragment of a protein that someone eats interacts with a specific antibody (immunoglobulin E) in their immune system. This antibody normally helps to protect us from infections, but it can lead to dangerous overreactions in some people. A survey in the United States found that almost 11% of people reported suffering from some kind of food allergy [24]. Other authors have stated that around 32 million people in the United States may be susceptible to life-threatening effects due to food allergies [22]. Consequently, the potentially adverse health impacts of introducing new sources of allergens into the food system are appreciable and should be taken seriously. The allergenicity of foods can sometimes be reduced by using processing methods to remove or deactivate them, such as fermentation, enzyme treatments, or heating [25]. But we still have a limited understanding of what makes some food proteins allergenic and others not [26]. It is therefore challenging to predict whether a new source of protein will cause allergies. Consequently, it is critical to test the potential allergenicity of new food products before they are introduced onto the market [27]. Food allergies and intolerances are increasing around the world and so it is important to consider their potential impact on human health when designing meat alternatives.

Not to Be Taken Lightly: Heavy Metals Heavy metals are natural metallic elements found in the Earth’s crust. Some heavy metals are essential to human life because they play critical roles in the physiological processes that occur inside us (like copper, iron, selenium, and zinc), whereas others are toxic even when consumed in relatively small amounts (like arsenic, mercury, and lead) [28]. Even the heavy metals that are essential to life become toxic when they are present in foods at sufficiently high levels. Consequently, it is important we have just enough of the beneficial heavy metals in our diet, while avoiding the bad ones. The heavy metals in our environment may come from human activities, like mining, industrial manufacturing, and agricultural practices. Others are produced by natural

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processes like soil erosion, volcanic eruptions, or weathering of the Earth’s crust. Heavy metals from natural processes and human activities contaminate our soil, water, and air and can therefore be absorbed by agricultural crops and pasture lands. They may also get into the livestock animals who consume the contaminated plants. If we eat plant- or animal-derived foods contaminated with these heavy metals, they can accumulate inside our bodies and interfere with our nervous, neurological, cardiovascular, gastrointestinal, immune, hormone, and reproductive systems, leading to problems such as cancer, diabetes, respiratory problems, and cognitive issues. These problems are particularly acute for pregnant women, infants, and children. Heavy metal accumulation has been reported in various kinds of plant-derived foods around the world, including rice, wheat, fruits, and vegetables [28]. Many of these are staple foods that form a large part of people’s diets, and so it is important we do everything we can to reduce their level of contamination to an acceptable level. Agricultural crops should not be grown near sites where there are high levels of heavy metal contamination. As a result of their potentially toxic effects on human health, researchers are developing new methods to treat soils contaminated with heavy metals to make them safer, such as using microbes that sequester and inactivate them [29]. Heavy metals may also be present in animal-derived foods, such as meat, fish, egg, and milk. Many kinds of wild fish contain relatively high levels of toxic heavy metals (Fig. 5.6), such as arsenic, cadmium, lead, and mercury [30]. They absorb these metals into their bodies from the surrounding water or from the foods they eat. There are numerous examples from around the world, including the New England coast near me, where the levels of toxic heavy metals in fish can exceed those considered safe. The fact that fish may contain appreciable levels of these toxic substances (especially mercury) is one of the main reasons the US government advises women not to eat wild fish

Fig. 5.6  Fatty fish in the wild are often contaminated with heavy metals like arsenic, cadmium, lead, and mercury that can be damaging to human health. (Picture of salmon from Timothy Knepp, Public domain, via Wikimedia Commons)

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when they are pregnant. People who regularly consume certain kinds of fish may also be prone to heavy metal poisoning. Switching to plant-based fish should help reduce this problem. Some meat products have also been reported to be contaminated with high levels of heavy metals [31]. However, there is still little information about the level of this problem and more research is needed. The challenge for us as consumers is that there is no way to look at a food and know whether it is contaminated with heavy metals or not. Expensive analytical instruments are needed that are only available in specialized scientific laboratories. Moreover, we cannot simply remove the heavy metals by washing or heating our foods (like we can remove or kill germs), because they are often located inside the foods and are chemically stable. We therefore rely on our governments to ensure the heavy metal levels in our foods are below the limits that may cause harm to us and our families, and trust that the food, fishing, and agricultural industries will follow these regulations. The levels of different heavy metals that cause harm have been established by careful experimentation, which has allowed government agencies to set maximum limits about the amounts that can be safely present in foods. In the United States, the USDA and FDA are working together on a Closer to Zero initiative, whose aim is to reduce the heavy metal content in our foods. In short, heavy metals are a major environmental and health concern in both animal- and plant-derived foods and it is important that governments and industry work towards reducing their levels in our foods. A recent study compared the levels of toxic metals in plant- and animal-based milks and found that the levels were relatively low in all of the samples tested and would not pose a major safety risk to human health [32]. More of these studies are needed for other kinds of food products.

A Growing Problem: Microplastics Over the past few years there has been an increasing number of alarming news stories about the negative impacts of microplastics on our environment [33]. Microplastics are the tiny particles that remain when discarded plastic-based materials, like cups, straws, cutlery, packaging, containers, or household goods, are eroded by natural processes like aging and weathering (Fig. 5.7). These particles may be as small as a few micrometers, which is around 100 times smaller than the human eye can detect. After being formed, microplastics may persist in our environment for years, where they can pollute our soils, rivers, oceans, and air. Indeed, it has been predicted that there will be more

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Fig. 5.7  Microplastics produced due to the fragmentation and erosion of plastics disposed into the environment can contaminate our foods. (Image of microplastics from Oregon State University (CC BY-SA 2.0))

plastics in our oceans than fish by 2050 if we continue on our current trajectory. Plastics may therefore get into our bodies when we breathe them in, or when we eat or drink contaminated food and water. Consumption of microplastics is of concern because they have been linked to adverse effects on human health and wellbeing [33]. Studies with animals have shown they can be absorbed into their bloodstream, tissues, and organs, where they can accumulate and cause damage. These harmful effects are partly because of the toxicity of the microplastics themselves but also because they can carry toxic substances they absorb from their environments, like heavy metals, pesticides, and other chemical pollutants. In 2022, a team of Dutch scientists collected samples of meat and dairy products from farms and supermarkets and measured the level of microplastics they contained [34]. Over 80% of the samples they tested contained microplastics. To identify the cause of this problem they also measured the levels of microplastics in the feed given to the animals, as well as in the blood of the animals. They found that all of the feed and blood samples they tested also contained microplastics. This was only a preliminary study, but it does raise concerns about microplastics getting into our bodies through animal-­ derived foods. Fish and other kinds of seafood have also been identified as a major source of microplastics in the human diet [35]. Our oceans and rivers are full of microplastics and so the marine animals we use as food can ingest

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or absorb them. As a result, the microplastics enter the human food chain and can have adverse effects on our health. There are some reports that microplastics can also get into foods derived from plants, like cereals, fruits, and vegetables, presumably by being absorbed through their roots, stems, or leaves. However, there are far fewer studies in this area. Thus, the consumption of microplastics may be a problem for carnivores, omnivores, pescatarians, vegetarians, and vegans. At present, however, the relative risk from these different types of diets is unknown and clearly more research is needed.

 ome Chemistry: Toxins Produced H During Cooking Cooking causes a complex series of chemical reactions to occur between the different kinds of molecules in foods, such as fats, proteins, carbohydrates, and minerals. These chemical reactions are responsible for many of the desirable colors, flavors, and textures of our foods. Cooking raw meat transforms it from a tough pinkish substance into a tender brownish substance that is more flavorful and easier to chew and swallow. Moreover, cooking inactivates harmful bacteria that can make foods unsafe to eat, such as Salmonella or E. coli.1 However, the same chemical reactions that lead to desirable colors, flavors, and textures can also generate potentially toxic substances. Cooking processed meat can lead to the formation of carcinogenic compounds, like polycyclic aromatic hydrocarbons, nitrosamines, and heterocyclic aromatic amines [36]. Studies with laboratory animals suggest these substances can cause cancer if regularly consumed at sufficiently high levels. There is therefore a need to better understand how much of these carcinogenic chemicals are formed in animal- and plant-derived foods during cooking, as well as the magnitude of their effects on our health. Dr. Monika Gibis is a German scientist who is an expert in the chemicals formed in meat products when they are cooked. A few years ago, she wrote an article on the formation of heterocyclic aromatic amines (HAAs) in cooked meat and their impacts on human health [37]. These toxic chemicals are generated when proteins and carbohydrates react with each other at the high temperatures used to grill, fry, and bake meat. HAAs are potent mutagens and carcinogens that can damage our DNA and promote the uncontrolled growth  Although cooking can usually kill most harmful bacteria, it may not deactivate some of the toxins that certain kinds of bacteria can produce in foods prior to them being consumed. 1

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of cancer cells. Studies of human eating habits and health suggest there is a link between the consumption of well-done meat products (which contain high levels of HAAs) and the risk of cancer. Other researchers have reported there are similar risks when consuming meat and seafood products that have been smoked [38]. Toxic chemicals, like polycyclic aromatic hydrocarbons, heterocyclic amines, nitrosamines, biogenic amines, and heavy metals, have been reported in smoked meat and seafood products at levels exceeding those recommended by government regulations. These products may taste great, but if you consume them often enough you increase your risk of a serious chronic illness. Other kinds of processing methods used to improve the taste or shelf life of meat products may also have adverse effects on our health. The World Health Organization placed processed meat products within their highest level (Group 1) of carcinogens to humans. Substances are placed into this category when there is convincing scientific evidence that they cause cancer in humans. This evidence mainly comes from epidemiological studies that show that people who eat high levels of processed meats are at a greater risk of getting cancer, especially colorectal cancer. The processed meats eaten most often are salted, cured, fermented, and smoked products made from beef or pork. This includes hot dogs, ham, sausages, corned beef, beef jerky, and canned meat. According to current guidelines, we should therefore avoid consuming too much of these processed meat products if we want to reduce our risk of cancer.2 We should not forget that plant-based foods also undergo chemical transformations when they are cooked or processed because they also contain fats, proteins, carbohydrates, and minerals that interact with each other. Consequently, they can also produce substances that have adverse effects on human health. However, there are differences in the types and amounts of molecules found in animals and plants, as well as the ways they are cooked, which may impact their potential to damage our health. Due to their relatively recent development, there have been far fewer studies on the potentially toxic chemicals formed in foods made from alternative protein sources (like meat, seafood, egg, or dairy analogs) during cooking and processing. Consequently, this will be an important area for scientists to focus on in the future. Conversely, some studies have reported that many plant-based foods contain natural substances (phytochemicals) that reduce the harmful effects of toxic substances in foods [39, 40]. This finding suggests that eating  It should be noted that some scientists have questioned the link between consuming processed meats and adverse health outcomes because they believe the strength of the evidence is too weak. 2

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plant-based foods may be less risky than eating animal-based ones. Moreover, eating plants with meat may reduce the harmful effects of any toxic chemicals produced during the cooking of the meat.

Global Pandemics When I first started planning this book, I did not even think about this next reason for not eating meat, but it has since become one of the most compelling arguments. Reducing meat consumption may help to prevent millions of people from dying and the global economy from crashing, by averting the next global pandemic [41]. A study published in the prestigious academic journal Science reported that zoonotic coronaviruses, which are viruses that can be transferred from animals to humans, have caused three major infectious disease outbreaks recently [42]: SARS (severe acute respiratory syndrome), MERS (Middle East respiratory syndrome), and COVID-19 (coronavirus disease 2019). The authors stated that nearly 90% of the RNA viruses that can cause health problems in humans are zoonotic. Other viruses that have had adverse effects on human health have also come from viruses originally found in animals: HIV from nonhuman primates; Ebola from bats; avian flu (H5N1 influenza) from birds; and swine flu (H1N1 influenza) from pigs. Zoonotic diseases are therefore a major concern to human health and wellbeing. At the time of writing, over a million people have already died from COVID-19 in the United States, and over six million people worldwide. We should therefore do everything we can to minimize the potentially devasting effects of zoonotic diseases. Indeed, in a recent United Nations report called “Preventing the Next Pandemic,” the top three issues putting us at risk of another devasting global pandemic were all related to the production and consumption of animal products. Reducing the amount of meat, eggs, and milk we consume would therefore greatly reduce the risk of global pandemics like the one caused by COVID-19 (Fig.  5.8) and other zoonotic diseases that could strike in the future. COVID-19 currently kills about 1% of the people it infects in the United States (and was much more deadly before we had vaccines) (ourworldindata. org). A future zoonotic disease could be much worse. Given the devasting impacts of these diseases on human lives and economies, we should certainly take seriously the potential health benefits of switching to a meat-less diet. The modern livestock industry feeds hundreds of millions of people with meat every day. The global production of beef, chicken, and pork is estimated to be over 340  million tons, which is equivalent to us eating 75  million

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Fig. 5.8  The risk of zoonotic diseases that transfer from animals to humans increases when we raise animals for food. (Image of coronavirus from Alissa Eckert, MS, and Dan Higgins, MAM (Public domain, via Wikimedia Commons))

elephants or 2.5 million blue whales a year. This is an enormous mountain of meat. To produce this much meat, the livestock industry must utilize large-­ scale industrialized feedlots, farms, and slaughterhouses. The animals are cramped into highly confined spaces under conditions where they are often stressed, which makes them much more vulnerable to catching and spreading diseases. In addition, tens of millions of livestock animals are transported around the globe annually [43], so there is more chance for diseases that have arisen in one place to spread to another. For instance, an animal contaminated with a virus could pass it on to other animals or people when it is shipped around the globe. Moreover, an increasing number of livestock farms are being located closer to wildlife, as forests are being cut down to house them, which means that diseases are more likely to be transmitted from wild animals to domesticated ones. All these factors mean that different viruses can share their genetic material and mutate into ever more diverse and dangerous forms. This is not only bad for humans, but also for livestock animals because they become more prone to catching diseases too. In 2018 and 2019, African swine fever (“pig Ebola”) swept through the pig population in China, resulting in most of them being slaughtered. This disease is incredibly contagious and deadly to pigs – nearly all pigs that get the disease die. It devastated the pork

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industry in China, with huge economic losses. China typically keeps around 440 million pigs, which is more than half the global population, because pork is one of the most popular foods there. The large rise in the cost of pork resulting from its scarcity therefore affected many people. Moreover, the price of pork also increased globally due to this pig pandemic, which put pressure on bacon lovers around the world. After the coronavirus hit, we all had to make drastic changes in our lives. Many of us were trapped in our houses most of the time, only venturing out for an occasional walk. No recreational shopping, eating out, going to the pub, watching sports, or working out at the gym. Everything stopped. If we want to reduce the risk of this happening again, are we willing to make a small sacrifice in our lives by eating less meat? Given the high quality of vegetarian and vegan foods available now, this may not even be a sacrifice at all.

My Takeaway Food safety is always an important concern when developing new food products. There would be important changes in the safety of our food supply if we transitioned to a meat-less diet. Eating more plant-­based foods would alter the risks from food poisoning by germs and chemical toxins, the rise of superbugs, global pandemics, contamination with microplastics, toxic substances produced during cooking, and the introduction of potentially harmful allergens. Due to the relatively recent development of many meat alternatives, there have been few systematic studies comparing their safety to that of the animal products they are designed to replace. Even so, it already seems clear that switching to a meat-less diet could have major benefits by reducing the risks of antibiotic resistance and zoonotic diseases. The health risks associated with these issues are huge, as demonstrated by the global COVID-19 pandemic, where millions of people have died, and economies have been devasted. I therefore believe that there is a strong argument for reducing the amount of meat in our diets from a food safety perspective. Even so, we still have to be vigilant and take all precautions necessary to reduce the harmful effects of toxins and allergens in our foods, whether they come from animals or plants.

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References 1. Yeung, M., Microbial Forensics in Food Safety. Microbiology Spectrum, 2016. 4(4). 2. Scharff, R.L., The Economic Burden of Foodborne Illness in the United States, in Food Safety Economics: Incentives for a Safer Food Supply, T. Roberts, Editor. 2018, Springer International Publishing: Cham. p. 123–142. 3. Holsinger, V.H., K.T. Rajkowski, and J.R. Stabel, Milk pasteurisation and safety: a brief history and update. Revue Scientifique Et Technique De L Office International Des Epizooties, 1997. 16(2): p. 441–451. 4. Gill, L.L., Is Our Meat Safe To Eat? 2022, Consumer Reports. p. 1–5. 5. Dewey-Mattia, D., et al., Surveillance for Foodborne Disease Outbreaks – United States, 2009–2015. Mmwr Surveillance Summaries, 2018. 67(10): p. 1–11. 6. Carr, T., Unclean greens: how America’s E coli outbreaks in salads are linked to cows, in The Guardian. 2020, The Guardian Group: Manchester, UK. 7. Scallan, E., et al., Foodborne Illness Acquired in the United States-Major Pathogens. Emerging Infectious Diseases, 2011. 17(1): p. 7–15. 8. Smulders, F.J.M., I. Rietjens, and M.D. Rose, Chemical hazards in foods of animal origin and the associated risks for public health: elementary considerations, in Chemical Hazards in Foods of Animal Origin, F.J.M. Smulders, I. Rietjens, and M.D. Rose, Editors. 2019. p. 21–47. 9. Atta, A.H., et al., Current perspective on veterinary drug and chemical residues in food of animal origin. Environmental Science and Pollution Research, 2022. 29(11): p. 15282–15302. 10. Ghirardini, A., V. Grillini, and P. Verlicchi, A review of the occurrence of selected micropollutants and microorganisms in different raw and treated manure  – Environmental risk due to antibiotics after application to soil. Science of the Total Environment, 2020. 707. 11. Bedale, W.A., Veterinary drug residues in foods of animal origin, in Chemical Hazards in Foods of Animal Origin, F.J.M. Smulders, I. Rietjens, and M.D. Rose, Editors. 2019. p. 51–79. 12. Trevisani, M., G. Fedrizzi, and G. Diegoli, Chemical hazards in meat and associated monitoring activities, in Chemical Hazards in Foods of Animal Origin, F.J.M. Smulders, I. Rietjens, and M.D. Rose, Editors. 2019. p. 315–340. 13. NIH. The end of antibiotics? NIH Medicine Plus Magazine 2022 [cited 2022]; Available from: https://magazine.medlineplus.gov/article/the-­end-­of-­antibiotics/. 14. CDC, COVID-19: US Impact on Antimicrobial Resistance. 2022, Centers for Disease Control and Prevention: Washington, D.C. p. 1–44. 15. Richie, H., How do we reduce antibiotic resistance from livestock? 2017, Our World in Data. p. 1–6. 16. McManus, P.S., et al., Antibiotic use in plant agriculture. Annu Rev Phytopathol, 2002. 40: p. 443–65.

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17. Valenta, R., et  al., Food Allergies: The Basics. Gastroenterology, 2015. 148(6): p. 1120–U64. 18. De Martinis, M., et al., New Perspectives in Food Allergy. International Journal of Molecular Sciences, 2020. 21(4). 19. Fasolin, L.H., et al., Emergent food proteins – Towards sustainability, health and innovation. Food Research International, 2019. 125. 20. Pali-Scholl, I., et al., Allergenic and novel food proteins: State of the art and challenges in the allergenicity assessment. Trends in Food Science & Technology, 2019. 84: p. 45–48. 21. Aimutis, W.R., Plant-Based Proteins: The Good, Bad, and Ugly. Annual Review of Food Science and Technology, 2022. 13: p. 1–17. 22. Hertzler, S.R., et al., Plant Proteins: Assessing Their Nutritional Quality and Effects on Health and Physical Function. Nutrients, 2020. 12(12). 23. Solymosi, D., et al., Food allergy? Intolerance? – Examination of adverse reactions to foods in 406 adult patients. Orvosi Hetilap, 2020. 161(25): p. 1042–1049. 24. Gupta, R.S., et  al., Prevalence and Severity of Food Allergies Among US Adults. JAMA Network Open, 2019. 2(1): p. e185630–e185630. 25. Pi, X.W., et al., Recent advances in alleviating food allergenicity through fermentation. Critical Reviews in Food Science and Nutrition, 2021. 26. Valenta, R., et  al., Molecular Aspects of Allergens and Allergy, in Advances in Immunology, Vol 138, F. Alt, Editor. 2018. p. 195–256. 27. Krutz, N.L., et al., Determination of the relative allergenic potency of proteins: hurdles and opportunities. Critical Reviews in Toxicology, 2020. 50(6): p. 521–530. 28. Munir, N., et al., Heavy Metal Contamination of Natural Foods Is a Serious Health Issue: A Review. Sustainability, 2022. 14(1). 29. Rajendran, S., et al., A critical review on various remediation approaches for heavy metal contaminants removal from contaminated soils. Chemosphere, 2022. 287: p. 132369. 30. Bosch, A.C., et al., Heavy metals in marine fish meat and consumer health: a review. Journal of the Science of Food and Agriculture, 2016. 96(1): p. 32–48. 31. Halagarda, M. and K.M. Wojciak, Health and safety aspects of traditional European meat products. A review. Meat Science, 2022. 184. 32. Astolfi, M.L., et al., Comparative elemental analysis of dairy milk and plant-based milk alternatives. Food Control, 2020. 116. 33. Wang, C.H., J. Zhao, and B.S. Xing, Environmental source, fate, and toxicity of microplastics. Journal of Hazardous Materials, 2021. 407. 34. van der Veen, I., et al., Plastic Particles in Livestock Feed, Milk, Meat and Blood. 2022, The Plastic Soup Foundation: Amsterdam, The Netherlands. p. 1–48. 35. Jin, M.K., et al., Microplastics contamination in food and beverages: Direct exposure to humans. Journal of Food Science, 2021. 86(7): p. 2816–2837. 36. Hadi, J. and G.  Brightwell, Safety of Alternative Proteins: Technological, Environmental and Regulatory Aspects of Cultured Meat, Plant-Based Meat, Insect Protein and Single-Cell Protein. Foods, 2021. 10(6).

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37. Gibis, M., Heterocyclic Aromatic Amines in Cooked Meat Products: Causes, Formation, Occurrence, and Risk Assessment. Comprehensive Reviews in Food Science and Food Safety, 2016. 15(2): p. 269–302. 38. Afe, O.H.I., et al., Chemical hazards in smoked meat and fish. Food Science & Nutrition, 2021. 9(12): p. 6903–6922. 39. Chung, R.T.M., Detoxification effects of phytonutrients against environmental toxicants and sharing of clinical experience on practical applications. Environmental Science and Pollution Research, 2017. 24(10): p. 8946–8956. 40. Rackauskiene, I., et  al., Phytochemical-Rich Antioxidant Extracts of Vaccinium Vitis-idaea L. Leaves Inhibit the Formation of Toxic Maillard Reaction Products in Food Models. Journal of Food Science, 2019. 84(12): p. 3494–3503. 41. Sprecht, L., Modernizing Meat Production Will Help Us Avoid Pandemics, in Wired. 2020: On-line. 42. Watsa, M., Rigorous wildlife disease surveillance. Science, 2020. 369(6500): p. 145–147. 43. Smiley, S. The Global Travels of Live Animals. 2020 [cited 2022]; Available from: https://www.globaltrademag.com/the-­global-­travels-­of-­live-­animals/.

6 Plant-Based Meat: Building Meat from Plants

Abstract  This chapter highlights the rapid advances in the development of plant-based meat alternatives. The basic building blocks needed to create plant-based meats are discussed, including proteins, carbohydrates, fats, colors, and flavors. The different methods of assembling these ingredients into meat analogs are then discussed, including processing technologies and soft matter physics approaches. The concept of food architecture is introduced, which involves the rational design of meat analogs from the bottom up. The importance of creating meat analogs that look, feel, and taste like real meat is highlighted, as well as designing these foods to have nutritional profiles that are similar or better than real meat. Finally, the environmental, health, ethical, and safety issues associated with switching to a more plant-based diet are critically assessed. Keywords  Food architecture • Proteins • Plant-based meat • Meat analogs • Extrusion • 3D printing • Nutrition • Ethics • Sustainability I have from an early age abjured the use of meat, and the time will come when men such as I will look upon the murder of animals as they now look upon the murder of men. Leonardo da Vinci

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 D. J. McClements, Meat Less: The Next Food Revolution, Copernicus Books, https://doi.org/10.1007/978-3-031-23961-8_6

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Turning Plants into Meat In essence, the meats from cows, pigs, sheep, and chickens are all plant-based foods. The animal’s bodies are built from plants, like grass, barley, oats, and corn. However, their digestive tracts (sometimes with the help of microbes) convert these plants into basic nutrients (proteins, fats, and carbs), which are then absorbed by the animal’s body and used to construct muscle cells through a complex network of integrated biochemical processes. As seen in earlier chapters, however, there are ethical, environmental, and health concerns associated with employing livestock to convert plants into human foods. It would be much better to simply eat the plants themselves. However, many people are so used to eating the flesh of animals that they find it hard to give up meat. One of the most exciting developments in the food industry over the past decade has been the use of advanced science and technology to create plant-­ based foods that look, feel, and taste just like real meat. The aim of the food companies working in this space is to create products that are more ethical and sustainable than real meat, but that meat eaters still love to eat. If you have two foods that taste the same, but one of them is much better for your health, animal welfare, and the environment, why would you not buy it? Of all the substances used to create alternatives to real meat, plants may be the strangest. As seen in later chapters, the tissues, cells, and molecules grown in bioreactors or extracted from insects have some similar features to those found in meat, which makes it easier to create meat-like products. In contrast, the biological elements of plants are very different from those found in animal flesh. The evolutionary branches of plants and animals diverged on the tree of life around a billion years ago. Since then, these two kingdoms of life have evolved different strategies to survive and procreate, which means the molecules, cells, and tissues they contain are very different (Fig.  6.1). Animals move around and need bones, muscles, and cartilage, whereas plants stand still and need roots, stems, and leaves. The strangeness of creating food products that mimic meat from plants can be seen if one tries to go the other way. I teach a graduate class on Future Foods at the University of Massachusetts. A good part of this course is spent talking about creating plant-based foods to replace animal-based ones, like meat, fish, eggs, and milk. But at the end of the course, I ask the students to work on a project where they have to create a meat-based fruit or vegetable. For instance, they may have to create an apple or a carrot using only ingredients from meat. We are so familiar with plant-based foods in our restaurants and supermarkets that we do not appreciate the complex science that has gone

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Animal-based Burger

Fig. 6.1  Plant-based meat products can be made to look, feel, and taste like real meat burgers, but they are more sustainable, healthier, and ethical (Images: See Figure Permissions for Credits)

into making them look, feel, and taste like real meat. In this chapter, I will therefore highlight some of the innovative ways food scientists are using to create plant-based foods, as well as some of the challenges they face.

The Structural Architecture of Meat To create delicious plant-based meat products it is important to understand the structural architecture of real meat. The reason beef, lamb, chicken, or fish taste the way they do is largely because of the types of molecules they contain, especially the proteins and fats, as well as the way these molecules are organized into complex structures in the animal’s flesh (Fig. 6.2). The most important structural elements in meat are the muscle fibers, connective tissue, and adipose tissue. These elements are organized into complex hierarchical structures within meat. To create authentic meat analogs, food scientists must therefore understand the structural architecture of these different elements. They can then use this knowledge to create similar structures from ingredients extracted from plants. During their lives, the main function of the muscle fibers in livestock animals is to allow them to expand and contract their muscles so they can move around [1]. Muscle fibers have been carefully shaped through hundreds of millions of years of evolution to allow animals to move. They consist of bundles of thin filaments of protein that provide both mechanical strength and flexibility to the living animal’s muscles. They also contribute to the desirable

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Fig. 6.2  The muscles in meat have complex hierarchical structures that are difficult to mimic using plant proteins. Muscle tissue contains bundles of small fibers packed into larger fibers that are wrapped by connective tissue. (Attribution: OpenStax, (CC BY 4.0), via Wikimedia Commons)

texture and mouthfeel of cooked meat. Muscle fibers are mainly assembled from two kinds of proteins: actin and myosin. These proteins are organized in a way that enables the contraction and expansion of the muscles driven by energy-generating cellular processes. The alignment of the muscle fibers inside meat is responsible for many of its unique sensory characteristics, including the way meat behaves inside our mouths when we chew it [2]. The structural architecture of muscle fibers is altered when we process meat, which is one of the reasons why burgers and sausages have different properties to beef steaks or pork chops [3, 4]. It is also altered by cooking, leading to changes in its texture and juiciness [5]. The high temperatures used during cooking cause an unraveling and reorganization of the complex structures inside meat, which leads to softening of the tissues, thereby making them more palatable [6].

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The connective tissue in animals helps to hold all the other components inside the muscles together – it is like a molecular scaffold and glue [1]. It forms thin sheets around the bundles of fibers inside the muscles (Fig. 6.2). The strength and amount of connective tissue in an animal increase as it ages, which influences meat quality, usually making it tougher to chew. The most important structural element inside connective tissue is collagen, which exists as a triple helix comprised of three intertwined protein chains [7]. At an animal’s body temperature, collagen exists as long rigid rods that make the connective tissue both strong and flexible. But when the muscles of an animal are cooked, the collagen unravels and becomes much more disordered and flexible [8]. This is one of the reasons that meat first softens when it is cooked. At longer cooking times, however, the meat hardens because some of the moisture is lost and because some of the muscle fiber proteins unravel and then stick tightly together. A good cook can therefore create different kinds of texture from the same piece of meat by changing the cooking times and temperatures to control these molecular events, leading to rare, medium, or well-­ done steaks. Adipose tissue is where most of the fat in an animal is deposited. In living animals, it plays several roles. It is used as a source of energy to power the muscles and other bodily functions [9], as well as to insulate the animal from the cold and regulate its energy uptake and use [10]. Adipose tissue is mainly assembled from fat cells, which consist of tiny pools of fat held inside cell membranes [11]. The fat cells in animals may be present in different locations, such as below the skin or as distinct regions within the muscle. In meat products, this latter kind of adipose tissue is referred to as “marbling.” The type, level, and location of the fat cells play an important role in determining the texture, mouthfeel, and flavor of meat [12]. It is therefore important for food scientists creating plant-based foods to mimic the behavior of these fat cells. Meat products come in many forms and some of them are much easier to mimic with plant-based ingredients than others. Whole muscle products, like beef steaks, pork chops, lamb shanks, and chicken breasts, have complex structural architectures like those found in the living animal. These structures are very difficult to simulate with ingredients isolated from plants, which is why there are far fewer of these kinds of plant-based products on the market. In contrast, comminuted products created by grinding meat up, like ground meat, sausages, and burgers, have structural architectures very different to those found in the living animal. These structures are much easier to mimic using ingredients from plants, which is why there are so many good quality plant-based products in this category, like the Impossible Burger or Beyond Burger.

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Plant-Derived Ingredients The first step in creating a plant-based meat is to select a suitable mix of ingredients. These ingredients may be whole or slightly processed parts of plants, like ground nuts, peas, beans, wheat, or mushrooms. Or they may be highly refined ingredients that have been extracted from plants and then purified, like proteins, carbohydrates, fats, colors, and flavors. Many of the ingredients used in the food industry come in the form of powders that can be mixed together in a suitable combination and then processed to create a plant-based food. The ingredients obtained from plants have different structures and properties than those obtained from animals, which makes it challenging to create plant-based foods that accurately mimic the desirable look, feel, and taste of real meat. A good deal of fundamental scientific knowledge is needed to choose the right ingredients and to put them together into meat-like products (Fig. 6.3). This knowledge is usually gained by scientists, engineers, and culinary experts working together in research and development laboratories. Once a suitable method has been discovered, then a “recipe” can be developed that the food manufacturer uses to produce the final product. Some of the most common ingredients that food scientists use to create plant-based meats are discussed here (Table 6.1).

Proteins

Starch

Fat Droplets

Dietary Fibers Salts

Fig. 6.3  Plant-based meat is assembled from different kinds of ingredients, including proteins, polysaccharides, sugars, fats, and salts. (Image of plant-based burger from Impossible Foods)

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Table 6.1  Food manufacturers use a broad range of ingredients to formulate plant-­ based meat products that look, feel, and taste like the real thing. A few examples are given here Ingredient

Purpose

Provides meat-like structures and textures, like firmness, chewiness, juiciness Binders Holds the different ingredients together into a solid mass Fats and oils Provides desirable textures and mouthfeel and carries oil-soluble nutrients, colors, and flavors Micronutrients Provide essential nutrients that might be missing from a plant-based diet Emulsifiers Helps to form and stabilize fat droplets Pigments Provides desirable color to the product. May be designed to change during cooking Flavors Provides meat-like flavor profile Texturizers

Preservatives

Protects the food from chemical or microbial degradation

Examples Plant proteins, starches, and gums Plant proteins, starches, and gums Plant-based fats and oils Vitamins and minerals Proteins and lecithin Natural colors

Flavorings, spices, herbs, sugars, salts Natural antioxidants and antimicrobials

Proteins Proteins are one of the most important ingredients for the successful formulation of plant-based meats because of their diverse functionality. They can create meat-like textures because they can be made to stick to other proteins and form networks. They can also bind other ingredients together and hold the fluids in a food, which is important to obtain a juicy mouthfeel [13, 14]. Moreover, they can stick to the surfaces of fat droplets and form a protective coating around them, which is important for simulating the adipose tissue in meat analogs. Proteins are also important because they are nutrients that are essential for our health. The proteins used as ingredients in plant-based foods are isolated from a diverse range of terrestrial plants, including soybeans, peas, wheat, corn, rice, mung beans, fava beans, and lentils. They may also be isolated from marine plants or microorganisms, like seaweed and microalgae. At the molecular level, proteins consist of long chains of amino acids that are linked together, like the beads in a pearl necklace. In nature, these chains tend to fold up into very specific structures whose shapes are governed by their intended function in the plant. These structures are the result of evolutionary pressures the plant and its ancestors have experienced throughout their billion year history. If you could look through an extremely powerful microscope, a plant protein molecule would look like a small compact blob. This blob is

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1 million times smaller

Earth ( 10 km)

Pea ( 10 mm)

1 million times smaller

Pea Protein ( 10 nm)

Fig. 6.4  Plant proteins are extremely small. For example, a pea protein is about a million times smaller than a pea, which is about a million times smaller than the planet Earth

only a few nanometers wide. To give you an idea of how small plant proteins are, it is useful to compare the size of a pea protein to that of a pea (Fig. 6.4). A pea protein is about a million times smaller than a pea, which is about a million times smaller than the planet Earth. In a typical plant-based burger there are about 200 million trillion proteins (2 × 1020), which is much greater than all the stars in the known universe. The blob-like proteins in plants are therefore very different from the fiber-like ones in meat, which means they typically produce foods with very different textures and structures. As we will see later, food scientists are developing innovative ways of coaxing these blob-­ like plant proteins into structures that resemble those in meat.

Carbohydrates Meat contains very low levels of carbohydrates, typically less than 1%. In contrast, plants often contain quite high levels. These carbohydrates can be extracted from plants and converted into ingredients used to create meat analogs. Plant carbohydrates come in several forms, which can be used to create different desirable attributes in plant-based meats. They can be divided into three main categories according to their molecular features and nutritional effects: sugars, starches, and dietary fibers. Sugars are white crystalline substances that easily dissolve in water and make our foods taste sweet, like the table sugar we sprinkle on our strawberries or spoon into our coffees. Sugars are used to improve the color and flavor of meat analogs. During cooking,

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sugars chemically react with plant proteins to generate a multitude of meaty aromas and brownish colors like those found in real cooked meat. Starches are long chains of glucose molecules (a type of sugar) linked together like a string of beads. They are commonly used by cooks and food scientists to thicken or gel foods, like the corn starch we use to make gravies, sauces, and puddings. Starches are sometimes used in plant-based foods to create meat-like textures and mouthfeels. But there are some potential drawbacks to using starch for this purpose. Starch is digested by enzymes in our guts, which releases the glucose so that it can be absorbed into our bodies. It therefore provides us with calories (which might not be a good thing if we want to lose weight) and increases our blood sugar levels (which could cause diabetes if we eat it too often). To produce healthier alternatives to real meat, the plant-based food industry would therefore be advised to reduce the levels of starch in their products. As a consumer, it is useful to check the label of a product to see how much digestible carbohydrates (total carbs minus dietary fiber) it contains. Like starch, dietary fibers consist of long chains of sugar molecules linked together, but they are not digested in our guts because we do not have the right enzymes. (Cows and sheep solve this problem by having a specialized compartment in their stomachs that hosts microbes capable of fermenting dietary fibers, such as the cellulose in grass, and converting them into sugars that they can absorb.) Dietary fibers do not therefore contribute to our calorie intake. Moreover, they may actually have some health benefits, like reducing constipation, colon cancer, and cholesterol levels. Thus, if we want to create healthier alternatives to real meat, we should include high levels of dietary fiber in plant-based foods. However, this is not always possible because these high levels can negatively affect the desirable flavors and mouthfeels of foods. For instance, plant-based meats containing high levels of dietary fiber may become too “gummy” or “slimy” when they are chewed. Even so, many dietary fibers are used as building blocks to create meat analogs because they can be linked together to form meat-like structures and textures. They also form polymer networks inside plant-based foods that trap water and other fluids, thereby contributing to the juiciness of meat analogs. Food formulators must therefore carefully select the different carbohydrate ingredients needed to create meat analogs with desirable colors, flavors, textures, mouthfeels, and nutrition.

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Fats Fats play a critical role in determining the desirable look, feel, taste, and nutritional profile of real meats. They stop the meat from drying out and burning during cooking. They carry desirable flavors and nutrients. They lubricate the mouth during chewing. They contribute to the feeling of fullness after a meal, reducing our tendency to overeat. It is therefore important to simulate these desirable attributes in plant-based meats. Fats suitable for use in these meat analogs can be extracted from a variety of oil-rich plants, including canola, cocoa, coconut, corn, flaxseed, olive, palm, rapeseed, safflower, seaweed, soybean, sunflower seed, and vegetables. Each of these fats has its own unique characteristics that make it more or less suitable for formulating different kinds of plant-based food products. Chemically, fats are mainly made up of molecules known as triglycerides, which consist of three fatty acids attached to a glycerol backbone. All triglycerides are not the same. The fatty acids may be attached to different positions on the glycerol backbone, they may have different numbers of carbon atoms, and they may vary in the number, position, and conformation (cis versus trans) of the double bonds they contain. Each type of fat therefore has its own unique nutritional profile, chemical stability, and solidity. Trans and saturated fats are often considered to be unhealthy, whereas polyunsaturated ones are considered to be healthy (Chap. 4). Unsaturated fats are more prone to oxidation than saturated ones, which means they tend to go rancid more easily. Saturated fats tend to be more solid at room temperature, whereas unsaturated ones tend to be more liquid. The solidity and melting behavior of fats plays an important role in determining the desirable texture and mouthfeel of meat products. It is therefore important for food formulators to select a source of plant-based fat that meets the nutritional and functional requirements of the product they are creating. Fats extracted from plants typically contain more unsaturated fatty acids than those found in animals (except fish), which influences their ability to accurately simulate the properties of real meat. When I was a kid, I used to stay with my granny during the summer holidays. She lived in a cottage in a beautiful village in the Yorkshire countryside. As a treat, she would let me take a piece of freshly baked white bread and scrape out the congealed beef fat from the baking tray after she had made the Sunday roast. This was a grayish white substance packed full of meaty flavors that were released in my mouth when the fat melted. There was always some leftover roast beef at the end of our Sunday dinner, which my granny would use for sandwiches for the next

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few days. After it had cooled down, roast beef contained distinct white veins of solidified fat that contributed to its desirable appearance, texture, and slicability. The unique solid-like and melt-in-your-mouth characteristics of beef fat are the result of the high level of saturated fat it contains. Similar characteristics are provided by the fats in chicken, pork, and lamb. The fact that most fats extracted from plants are highly unsaturated means they tend to be liquid at room temperature and so they cannot mimic the desirable structure-­ forming and melting characteristics of animal fats. Food scientists are therefore trying to find fats that can be extracted from plants that accurately simulate the desirable solidity and melting characteristics of animal fat. Fortunately, there are some plant-derived fats that are solid at room temperature and melt in the mouth, like coconut oil, cocoa butter, and palm oil. But all of these contain relatively high levels of saturated fats, which have been linked to health concerns, such as heart disease [15]. However, some nutritionists now dispute this claim [16]. The level of unsaturated fats in foods is also important because it impacts their nutritional benefits and shelf lives. Consuming fats with high levels of polyunsaturated fatty acids (PUFAs), especially omega-3s, has been linked to beneficial health effects, including reducing the risk of heart disease and improving brain development [17, 18]. Most animal fats contain low levels of omega-3s but fish oils contain high levels of them, which is one of the reasons that eating seafood is so healthy for us. Most of the fats and oils extracted from plants are poor sources of omega-3s but there are a few exceptions. Flaxseed and algae oils contain high levels of omega-3s and may therefore be used as a plant-based alternative to fish oils in meat and seafood analogs. Some agricultural technology companies are using advanced crop breeding and genetic engineering approaches to create new breeds of food crops that naturally produce high levels of omega-3s, such as soybeans. Similarly, some biotechnology companies are raising and harvesting microalgae that are rich in omega-3s for use in plant-based foods as replacements for fish oil. One of the major challenges the food industry faces when fortifying our foods with healthy omega-3s is that they tend to oxidize during food processing and storage, which generates unpleasant flavors and potentially toxic reaction products [19, 20]. The oxidation of these healthy fats can be slowed down by adding natural antioxidants, like plant extracts. In my laboratory, we have used nanotechnology to stabilize omega-3s by including them in tiny particles that also contain antioxidants. Even so, food manufacturers must still carefully package their products to prevent them from coming into contact with oxygen and other substances that can cause them to go rancid. They must also carefully control the exposure of their products to heat and light

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during storage and transport because these factors also promote oxidation. Indeed, a great deal of advanced science and technology goes into incorporating these healthy fats into our foods in a stable form.

Special Effects: Colors and Flavors Real meat, like roast beef, chicken breast, or lamp chops, has a unique look, smell, and taste. Plant-based meat analogs should therefore be designed to mimic the specific appearances and flavors of the meat products they are designed to replace. This requires knowledge of the physics and chemistry of foods. The appearance of a food is a result of light waves bouncing off its surface and entering our eyes. The overall optical properties of foods are governed by two main features of the interactions of light waves with their surfaces: scattering and absorption. Scattering occurs when the direction that light waves move is changed when they encounter particles inside the food (like fat droplets or protein fibers) or they bounce off the rough surfaces of foods (the surface of meat after cooking looks like a lunar landscape). This is one of the reasons why meat goes from looking shiny when it is raw to looking matt when it is cooked: when meat is cooked its surfaces dry out and become much rougher, which leads to scattering of the light waves in all directions. Absorption occurs when the light waves are selectively absorbed by pigments inside the food. Normal white light actually consists of a mixture of different colors, such as red, orange, yellow, green, blue, indigo, and violet. Raw beef contains pigments (such as hemoglobin or myoglobin) that absorb green to violet light, but not red light. As a result, when light reflects from the surfaces of meat it appears red because all of the other light waves are absorbed. The manufacturers of plant-based meat analogs want to create products that look exactly like real meat. Ideally, they would like to mimic the appearance before, during, and after cooking so meat analogs behave just like a real meat product when consumers are preparing them. For this reason, there has been great interest in discovering natural pigments in plants (or other non-­ meat sources) that can be used to simulate the behavior of those in meat products. Different manufacturers have developed different strategies to do this. Beyond Meat uses a natural extract from beetroots. This pigment has a reddish color at room temperature but turns brown when heated. In contrast, Impossible Foods uses a very different approach, which is based on genetic engineering. They use microbes to produce a form of plant hemoglobin (leghemoglobin), which was originally found in the roots of soybeans. This molecule is almost identical to the hemoglobin found in real meat and

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therefore gives meat analogs a similar color, changing from red to brown when they are cooked. The leghemoglobin is produced using a process known as precision fermentation, which is a powerful technology that is revolutionizing the food industry, and is discussed more in the following chapter. Meat also has a characteristic flavor that people are familiar with. The plant-­ based food industry therefore wants to create meat analogs that accurately mimic the flavor of real meat so as to attract more meat eaters to their products. Flavor is actually a highly complex phenomenon involving interactions between molecules in our foods with different kinds of receptors in our noses and mouths. The three most important elements of meat flavor are aroma, taste, and mouthfeel. Aroma is due to the presence of volatile molecules that rise from the food and form a mist that gets into our noses, either before or after putting the food into our mouths. These volatile molecules then interact with the receptors in our noses. There are around 400 different kinds of receptors in the typical human nose, which can detect different kinds of aroma molecules. The precise pattern of aroma molecules that stimulate these receptors is responsible for the unique flavor perceived. Cooked meat contains a specific combination of different kinds of volatile molecules that are responsible for its characteristic aroma. These molecules may be naturally present in the meat, or they may be generated by complex chemical reactions that occur when the meat is cooked. Researchers have reported that there are hundreds of different aroma molecules responsible for the flavor of meat products. Food manufacturers must also mimic the taste of meat products, which is often easier than the aroma. The taste of a food is due to the presence of non-volatile molecules that mainly interact with taste receptors on our tongues. The five major tastes are sweet, sour, bitter, salty, and savory (“umami”). The mouthfeel of a food is due to receptors located in our mouths that sense pressure and movement. It is responsible for sensations like toughness, juiciness, and gumminess. Plant-based food manufacturers must therefore formulate their meat analogs so they can simulate the aroma, taste, and mouthfeel of different kinds of real meat products. Again, this is highly challenging because of the unique combination of molecules found within meat. Ingredient suppliers have created a diverse range of flavoring agents to mimic the desirable flavor and mouthfeel of meat products, including salts, sugars, spices, herbs, and flavor extracts [21]. The scientists working for ingredient manufacturers carry out research using some of the same analytical instruments used by forensic scientists, like nuclear magnetic resonance, chromatography, and mass spectrometry, to identify the key constituents within both raw and cooked meats that lead to their unique flavor profiles. They then use this knowledge to find substances in plants that can be extracted and

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converted into flavoring ingredients. Alternatively, they may use chemistry or biotechnology approaches (like smoking or fermentation) to create them. In the case of fermentation, different kinds of meaty flavor can be generated by using different kinds of microbes (bacteria, molds, or yeast), raw materials (such as soy, wheat, or peas), and conditions (such as time, temperature, and humidity). Some of the ingredients extracted from plants naturally contain off-notes that can give plant-based foods an earthy, chalky, astringent, or bitter taste. Ingredient manufacturers are therefore developing innovative strategies to overcome this problem, including creating flavor blockers or maskers that stop the off-flavors from interacting with the receptors in our mouths. Alternatively, they may process the ingredients to remove or deactivate these off flavors.

The Food Artists Palette: Plant-Based Ingredients Like artists using different colored paints to create a picture, food scientists use different ingredients to create plant-based meat analogs that mimic the unique look, feel, and taste of real meat. These ingredients are usually obtained by disassembling plant materials (such as roots, leaves, stems, fruits, or seeds) into their basic constituents (proteins, carbohydrates, fats, colors, and flavors). The ingredients obtained can then be reassembled into meat analogs using a combination of art, craft, and science. Just as artists’ paints come in different forms, such as pastes, oils, solutions, solids, and powders, so do food ingredients. The majority of plant-derived ingredients are sold in a powdered form that must be mixed with water and other ingredients before they are used. However, some of them also come as pastes, oils, solutions, or solids. For instance, fats may be bought as liquids (like canola oil) or solids (like cocoa butter) depending on their melting behavior. Ingredient companies play a critical role in the modern food industry. Some of these companies specialize in specific kinds of ingredients, such as proteins, fibers, colors, or flavors, whereas others sell a broad spectrum of different ingredients. These companies scour the Earth to find plants that contain the constituents needed to create food ingredients with the required properties, but that are also economic, reliable, abundant, and sustainable. After identifying a suitable botanical source, they must develop economic manufacturing processes to break down the plant materials into their constituents, without damaging them. They must then purify the ingredients to remove undesirable substances that could cause quality defects or health problems, such as off-flavors or toxins.

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A plant-based meat analog may be assembled from ingredients extracted from numerous kinds of plants found in different regions of the world. As an example, a popular plant-based burger contains ingredients from peas, canola, coconuts, rice, cocoa beans, potatoes, sunflowers, beets, lemons, and apples (Fig. 6.5). These ingredients must all be transported to the factory where the meat analog is produced. In some cases, the ingredients must be shipped long distances around the globe before they are assembled into the final product. Coconut oil typically comes from Asian countries like the Philippines, Indonesian, and India, whereas cocoa butter comes from West African countries like the Ivory Coast, Ghana, Nigeria, and Cameroon. The biggest producers of sunflower are European countries like Russia, Ukraine, and Romania. Potatoes mainly come from China, India, Russian, and Ukraine. Transporting ingredients around the world requires fossil fuels to power boats, trucks, trains, and refrigerators, which impact greenhouse gas emissions and global warming. Moreover, global supply chains are often fragile, as seen by the disruptions caused by COVID-19, the Russian invasion of Ukraine, and extreme weather events linked to global warming. The processing operations needed to extract ingredients from plants depend on the nature of the ingredient and the plant. Edible fats are usually extracted from oil-rich plants like coconuts, cocoa beans, or canola seeds in large

Fig. 6.5  Plant-based burgers may be assembled from many different ingredients. For instance, the Beyond Meat burger is made from peas, canola, coconuts, rice, cocoa beans, potatoes, sunflowers, beets, lemons, apples, and other ingredients. (Images: Creative Commons – see Figure Permissions)

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industrial-­scale factories that look like oil refineries using various approaches. The raw plant materials may be put inside industrial-scale presses to squeeze out the fats. They may be mixed with organic solvents (like hexane) to dissolve the fats, which are then collected by evaporating the solvents. In this case, there are environmental concerns about disposing of the organic solvents. Alternatively, plant tissues may be physically, chemically, or enzymatically treated to break them down and release the fats, which can then be collected by centrifuging or filtering. Proteins and carbohydrates are extracted from raw plant materials using processes like soaking, grinding, mixing with strong acids or alkalis, heating, precipitation, centrifugation, and filtration. The precise combination of processes used depends on the type of ingredient being extracted. Ideally, these processes should be able to isolate pure ingredients with well-defined properties and behaviors. In practice, they are often harsh and damage fragile ingredients (especially proteins), which makes them challenging to use when creating meat analogs because their performance is inadequate or inconsistent. The manufacturing processes used to extract and purify the ingredients from plants often involve considerable quantities of fossil fuels and water, and they often generate large amounts of waste materials, which have a negative impact on our environment. The food industry is therefore being pushed by consumers and regulators to develop more environmentally friendly practices. Manufacturing operations are being redesigned to minimize water and energy use, as well as to convert waste materials into valuable products rather than dumping them into the environment. Ideally, an ingredient factory should take in a raw material from plants, and then use sustainable processes to dissemble it into a wide variety of useful ingredients that can be used in foods or other industries. For instance, soybeans may be converted into soybean oil, lecithin, protein, and dietary fiber that can be used as food ingredients, and the rest can be converted into animal feed. Another issue food manufacturers must consider is the ethics of the ingredients they use to formulate their products. Consumers are increasingly concerned about the negative impacts of some commonly used food ingredients on the environment, biodiversity, and local communities. Concerns have been expressed about the use of palm oil to formulate plant-based foods because of several ethical issues linked to its production. There is evidence that children are being forced to work on palm fruit plantations to gather the palm kernels. The employees of this industry are often exploited, with poor pay and working conditions. Countries where palm trees are grown, such as Indonesian and Malaysia, are cutting down rainforests to increase the land they have to grow palm trees, which is leading to biodiversity loss and environmental

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destruction. Many consumers are therefore pushing the food industry to ensure that palm oil is produced more ethically and sustainably. When we bite into a plant-based food, we do not usually think about where the ingredients came from, how they were transported, stored, and processed, and the environmental and social impacts linked to their use. Food companies typically have a team of people whose job is to deal with these issues. Ideally, meat analogs should be produced using sustainable ingredients that do not negatively impact our environment, as well as to ensure that all of the people involved in the food supply chain are treated fairly and given a living wage. This requires consumers to demand more ethical and sustainable products, as well as regulators and governments to create an environment that encourages their creation.

Food Architecture: Assembling Plant-Based Meats Like an artist staring at a blank canvas or an architect gazing at an open space, a food manufacturer must first decide what to create and how to create it. An artist has a palette of different colored paints. An architect has different kinds of building materials, including bricks, cement, glass, and wood. A food manufacturer has a range of different ingredients that perform different functions (Table 6.1). Some ingredients provide solidity, chewiness, and juiciness, others give desirable colors and flavors, and others protect the product from deterioration. The manufacturer must select just the right combination of ingredients to get the desired aesthetic effects required in the final product, such as the look, feel, and taste of real meat. Moreover, these ingredients must be affordable, healthy, and sustainable. The food designer must use their knowledge of chemistry, physics, and engineering, as well as some art and craft, to assemble the ingredients into a desirable final product. I now consider the science and technology being used to turn ingredients extracted from plants into products that resemble real meat.

Designing and Building Meat Analogs Different approaches are being used to assemble plant-derived ingredients into meat-like products. Some of them are simple cook-and-look approaches, whereas others are much more sophisticated approaches that rely on a deep understanding of what is happening at the molecular level inside foods. The cook-and-look approach involves mixing different ingredients together (such

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as water, texturizers, binders, colors, flavors, and preservatives), shaping them, cooking them, and then seeing what kind of product is created. If the formulation or processing method does not give the required look, feel, and flavor, then it is changed, and the process is repeated. Eventually, a plant-based product with properties similar to real meat may be achieved. In contrast, the fundamental science approach uses an understanding of how the different ingredients in a food interact with each other to organize them into structures that create meat-like properties. I refer to this approach as food architecture – the practice of rationally assembling different building blocks into designed structures that provide a certain function and aesthetic. At the simplest level, a food architect combines the various ingredients together (such as proteins, oils, fibers, sugars, salts, colors, and flavorings) and then processes them (shears, extrudes, or heats) to create meat-like structures, textures, and flavors. Typically, these processes cause the plant proteins to unravel and stick to their neighbors, thereby creating fibrous structures and giving a firm texture. There are two main approaches used to create plant-­ based meats, which can be categorized according to the way the structures and textures are formed: machining and molecular design approaches.

Machining Meat Analogs In the food industry, the machines used to mix, shape, and cook meat analogs are specialized pieces of equipment that are part of large-scale production lines that produce tons of food per day. The most common machines used for this purpose are extruders and shear cells, but some innovative approaches are being developed like 3D printers. These machines are often designed to create fibrous structures inside plant-based products that mimic those found in real meat. Some of these machines are scaled-up versions of devices you might find in your kitchen, whereas others are very different.

Extruders An industrial-scale extruder consists of a set of giant metal screws that mix the ingredients and then force them through a small hole (the “die”) into the required shape (Fig. 6.6). This machine is heated so that the ingredients are simultaneously mixed, cooked, and shaped. Typically, the food manufacturer mixes all the ingredients together and then pours them into a hole in the top of the extruder. The screw then pulls them in and pushes them through the

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Fig. 6.6  Extruders are commonly used for large-scale production of plant-based meat. The ingredients are pushed through the extruder by a large screw while being mixed, sheared, and heated. (The image of the extruder was kindly provided by Professor Lutz Gross (University of Massachusetts))

machine where the proteins, carbohydrates, fats, and other ingredients are mixed together and cooked. Finally, the semi-solid mass created is forced through the die at the end of the machine and cut into meat-shaped products. Inside the extruder, a series of highly complex molecular events occurs that scientists are still trying to understand. One of the most important of these events is the unraveling and clumping together of the protein molecules, which leads to the formation of a semi-solid mass. Moreover, the intense shearing forces inside the device create fibrous structures inside this mass. Extruders are already commonly used in the food industry to create products like pasta, breakfast cereals, snacks, and pet foods, and these same devices can easily be adopted for use by the plant-based food industry. They are relatively inexpensive to run and can process large amounts of foods in a relatively short time, which makes them particularly suitable for creating plant-based meats. However, they do use a lot of energy, and it is difficult to accurately simulate the delicate structures of whole muscle meats like roast beef, pork chops, and chicken breast. Instead, they are much more suitable for creating products like burgers, nuggets, and sausages that have less sophisticated structures.

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Shear Cell Technology Another machine developed to create plant-based meats is the shear cell technology, which was originally developed in the early 2000s at Wageningen University in the Netherlands – often considered to be the MIT of food science. This technology has been adopted commercially to produce meat analogs by a start-up company known as Rival Foods that was co-founded by Dr. Birgit Dekkers, who did her doctoral research in food science at Wageningen. Rival Foods employs a team of product developers and mechanical engineers to use the shear cell technology to create delicious and sustainable plant-based meat products. Their machine basically consists of a giant metal cylinder that spins around at high speeds and is heated, which mixes, structures, and cooks the plant-based ingredients leading to the formation of plant-based meat analogs (Fig.  6.7). During this process the plant proteins unravel and stick to their neighbors, which leads to the formation of meat-like fibrous structures [22]. An important advantage of the shear cell technology over extrusion is that the shearing conditions can be precisely controlled to create more sophisticated meat-like structures. Indeed, Birgit and her team have already shown

Fig. 6.7  The shear cell technology has been developed to create plant-based meat and seafood analogs. It consists of a large metal cone that is placed in a mixture of heated ingredients and spins around at high speeds. (The image of the shear cell was kindly supplied by Prof. Atze Jan van der Goot. The image of the plant-based chicken was kindly provided by Rival Foods)

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they can create whole muscle meat and seafood analogs with appearances, textures, and mouthfeels very much like real meat, including chicken, beef, and fish.

3-D Printers I first came across the idea of 3D printing of foods when I was invited to attend a meeting in Boston organized by Eric Bonabeau, who was a “complexity theorist.” He had secured funding from NASA to create a device that could be used by astronauts on long-haul space missions to print any food they desired. One of the past commanders of the International Space Station talked about the adverse effects of conventional space foods (basically mush in a bag) on the mental health of the astronauts. We often take it for granted, but eating is one of our most pleasurable sensory experiences. When we do not have access to varied and delicious foods, we can become depressed and undereat, increasing our risk of malnutrition. This is obviously a big problem for astronauts on long-haul space missions. Eric and his team of food scientists and engineers aimed to create a 3D printer that was similar to the food replicator on the Starship Enterprise from the classic sci-fi series Star Trek. An astronaut would type in the kind of food they wanted into a keyboard, and then the 3D printer would create it for them. Someone might miss their wife’s Sunday roasts, whereas others missed a Chicago-style pizza. At the press of a button, voila, there it is. Thus, keeping the astronauts happy and eating well. At the time, I thought this was a crazy idea that would never work. In the early 1970s, I also thought that the handheld devices the crew of the original Star Trek Enterprise used to communicate with each other, which allowed them to see an image of the person they were talking to on a small screen, was also crazy – so I am no great futurist. Now, anyone can buy a 3D food printer for a few hundred dollars. There are many kinds of 3D printers, but the most common one used to print plant-based foods consists of a syringe that contains edible inks, which can be moved in a horizontal and vertical direction relative to a platform that the food is printed on (Fig. 6.8). The edible inks are typically made from mixtures of proteins, carbs, fats, and water. Different inks may be used to print different parts of a meat or seafood analog. A reddish protein-rich ink may be used to print the lean part of a bacon analog, whereas a whitish fat-rich ink may be used to print the fatty part. Initially, the food to be printed is designed using a computer program, which tells the instrument where the different inks should be printed. An edible ink is then placed in the syringe and the

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Fig. 6.8  3D printers are being used to create plant-based meat and seafood products, like the salmon analog produced by the Austrian company Revo Foods (www.revo-­ foods.com), which is printed in a facility containing multiple printers. (Images kindly provided by Revo Foods)

printer is started. The nozzle of the syringe moves over the printing platform and deposits small amounts of edible ink at the locations where the computer program tells it to. The device prints the food one layer at a time until it builds up the complete food. The food may be cooked as it is printed by heating the nozzle or printing platform, or the printed food can be collected and placed in an oven to cook it. Several innovative food companies are already producing plant-based meat and seafood analogs that closely mimic the look, feel, and taste of the real versions using this technology, including Redefine Meat in Israel, NovaMeat in Spain, and Revo Foods in Austria (Fig. 6.8). Some of the main drawbacks of conventional 3D printers are that they can only print one food product at a time, they are relatively slow, and they must be cleaned regularly. They are not therefore suitable for the mass production of meat analogs, but they can be used to create smaller batches for niche markets. Revo Foods increases their production speeds by having a facility that contains multiple printers. Redefine Meat does this by printing multiple meat analogs with a single printer. They do this by printing a large block of material with an internal structure that resembles meat and then slicing it into steaklike shapes.

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Individual 3D printers are ideally suited for creating customized plant-­ based meat analogs in home, restaurant, or hospital kitchens. The texture, flavor, and nutritional profile of these products can be tailored to the needs of each individual. I may want a firm burger with an intense flavor that is fortified with cancer-fighting curcumin, but you may want a soft burger with a mild flavor that contains cholesterol-lowering phytosterols.

Molecular Design of Meat Analogs Currently extrusion is the most common method of mass-producing meat analogs, but extruders are expensive to buy and require large amounts of energy to run. Researchers are therefore developing alternative ways of creating meat analogs using methods that do not require specialized equipment or involve high energy costs. In my laboratory, we used soft matter physics approaches to achieve this goal. Many people may be unfamiliar with this term. Traditionally, physicists work with solids, liquids, or gasses. Solids are usually hard and have definite shapes (think of a brick), whereas liquids flow (think of water). However, many materials of interest to humans, including most foods, have intermediate properties: they are partly solid and partly liquid. A lump of lard keeps its shape on the plate but flows when a knife is scraped across it. These kinds of materials are referred to as soft solids. Soft matter physics is the branch of science that has arisen to understand, control, and predict the properties of these materials. Food scientists are employing the advanced concepts from this relatively new branch of physics to better understand and design meat analogs. As an example, I will describe a soft matter physics approach used in my lab to create meat analogs with structural architectures and properties that mimic those of real meat. As mentioned earlier, the muscle tissues in meat consist of bundles of very thin fibers that are mainly assembled from meat proteins (Fig.  6.2). My research group tries to simulate these thin fibers by heating plant proteins (like those from peas) so they unravel and stick together in long chains, like pearls in a necklace. We then mix these protein chains with a dietary fiber (like the pectin from oranges or apples). Under the right conditions, the protein chains and dietary fibers separate from each other due to a phenomenon called “thermodynamic incompatibility” (basically the proteins and dietary fibers prefer their own company rather than being together) leading to a protein-rich and a fiber-rich region. When this mixture is gently stirred it forms a fibrous structure that can be set in place by adding a gelling agent. We use an enzyme isolated from bacteria, known as transglutaminase,

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Fig. 6.9  Plant-based meat and seafood can be created using soft matter physics approaches. In our laboratory we have made plant-based scallops using this approach. (Images kindly provided by Kanon Kobata and Kevin Zhang, University of Massachusetts)

to crosslink the protein molecules and form a semi-solid material that resembles meat. My students have created plant-based scallops from pea proteins and citrus pectin using this approach (Fig. 6.9). Soft matter physics can be used to produce plant-based meats and seafood using simple equipment with low energy costs, which should lead to more affordable and sustainable commercial products.

Data-Driven Design As I was finalizing this chapter, I was contacted by Dr. Oliver Zahn out of the blue and we had a great conversation about the future of food design. Oliver has a really interesting history. He was trained as an Astrophysicist at Harvard University and then went on to be the director of UC Berkeley’s Center for Cosmological Physics together with two Nobel laureates. He also worked as a lead data scientist at Google, SpaceX, and Impossible Foods. Oliver is extremely passionate about making the world a better and fairer place through science and technology. He has been a committed vegan for many years to reduce the level of animal suffering in the world and to minimize the devasting effects of food production on our environment. He also has a passion for

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good food. His unique combination of skills and passions led him to found his own start-up company, Climax Foods, which is based in Berkeley, California. The team of scientists at Climax Foods are employing the latest advances in data science and machine learning to design a new generation of plant-based foods that will outcompete their animal-based predecessors. They do this by reverse engineering animal-based foods. Initially, a series of plant-­ based food prototypes is created using different combinations of ingredients and preparation procedures and then their look, feel, flavor, and microbial profile are characterized using an array of advanced forensic methods. The same approach is used to characterize the properties of the target animal-­ based products they are trying to mimic. The data obtained is then fed into a series of sophisticated machine learning programs that help to identify the optimum recipe for producing a plant-based food. For instance, there may be a program for flavor, another for texture, and another for the microbial profile. Oliver told me that the plant-based products he and his team have created much more accurately simulate the properties of animal-based products than any of the existing products on the market. Climax Foods is starting with dairy products like cheese but is also exploring the same data-driven approach for creating plant-based meat and seafood products.

Are Plant-Based Foods Better for Our Planet? So far, we have seen how meat analogs can be created from plant-based ingredients, but what are the advantages of eating them rather than real meat? As discussed in Chap. 2, there is strong evidence that plant-based foods are more sustainable and have fewer negative impacts on our environment than animal-­ based equivalents [23]. Livestock animals are inefficient at converting their feed into meat. For instance, feeding 100 calories of grain to chickens, pigs, or cows produces about 12, 10, or 3 calories of meat, respectively [24]. As a result, many more of our valuable resources are required, and much more pollution and greenhouse gasses are produced, when we raise animals for food rather than simply growing plants that we eat directly. For instance, life cycle analyses have shown that replacing meat burgers with plant-based ones could reduce greenhouse gas emissions, water use, land use, and pollution by around 90% (Table 6.2). This is a huge change. It is therefore much better to feed plant-based foods directly to humans, rather than to feed them to animals, which then convert them into flesh that we eat. The reason livestock animals are not very efficient at converting feed into meat is that some of the calories they eat are used to create body parts we don’t eat (such as bones, hooves, and

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Table 6.2  Environmental benefits of plant-based burgers. Reductions in greenhouse gas (GHG) emissions, land use, water use, and pollution due to eutrophication Product Impossible Burger Beyond Burger Black Bean Burger Quinoa Burger

GHG emission reduction

Land use reduction

Water use reduction

Pollution reduction

89%

96%

87%

91%

90% 89%

93% 97%

99% 96%

– 76%

90%

93%

98%

73%

Data from the Good Food Institute [25]

horns), as well as to provide energy to maintain their bodily functions, like breathing, pumping the blood around their bodies, keeping warm, thinking, and moving around. Some researchers have argued that it is possible to raise livestock in a way that makes them net-carbon sinks  – they reduce greenhouse gas emissions because they eat carbon-rich grass and produce manure that traps the carbon in the soil. However, this only seems to be true for sparsely grazed grasslands where there are very few cattle on a given area [26, 27]. As well as being an inefficient way of producing our food, there would be an even greater reduction in greenhouse gasses if this land were simply rewilded. Simply reducing the total amount of meat we eat would free up more land, which would have a much greater impact on our environment. Moreover, we are having to convert some of our critical natural resources (like the rainforests) into agricultural land to grow crops to feed livestock animals, which is causing a huge increase in biodiversity loss. There, therefore, appears to be very strong arguments for adopting a more plant-based diet to reduce the negative impacts of food production on our environment. Even so, it should be noted that there are large numbers of farmers and communities around the world that rely on meat and other animal products as part of their livelihoods, and that there are areas around the world that are unsuitable for growing agricultural crops, but that can still be used to raise livestock animals [28]. Consequently, the environmental benefits of transiting to a plant-based diet must be weighed against the economic and societal impacts.

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Is Plant-Based Meat Healthier? Will substituting plant-based meat for real meat make us healthier? There appears to be strong evidence that certain kinds of animal-based foods, particularly processed red meats, are linked to an increase in chronic diseases, such as cardiovascular disease, cancer, diabetes, and stroke [29]. Indeed, the World Health Organization classifies red meat and processed meat as potential carcinogens. Consequently, there should be health benefits from reducing the amount of these kinds of foods in our diet. This could be achieved by replacing real meat with plant-based alternatives, but it could also be achieved by consuming more chicken or fish. It is often assumed that adopting a more plant-based diet will improve our health [30], but this depends on the type of plant-based foods we consume. Real meat and seafood are good sources of certain types of vitamins and minerals (especially vitamin B12, vitamin D, calcium, iron, and zinc), which are often difficult to obtain from a diet consisting only of plant-based foods. As a result, it may be necessary to fortify plant-based meats with these micronutrients to avoid nutritional deficiencies (especially for vegans). As discussed in Chap. 4, animal proteins contain all the essential amino acids required to maintain human health, whereas many plant proteins are lacking in some of them. As an example, cereal proteins such as those from wheat, rice, corn, barley, and oats tend to have relatively low levels of lysine, whereas legume proteins such as those from kidney beans, chickpeas, peas, and lentils have relatively low levels of methionine and cysteine [31]. If you only ate one type of plant-based food, and the total amount of protein in your diet was limited, then you may become deficient in some of these essential amino acids, which would cause you to become sick. However, this is rarely a problem in developed countries because most vegetarians and vegans consume proteins from a broad range of sources. Another potential problem is that our bodies cannot fully digest and absorb the proteins in certain kinds of plant-based foods. Some sources of plant protein contain antinutritional factors (ANFs) that inhibit the digestion and absorption of proteins and other nutrients [32]. ANFs may exert their effects through various mechanisms, including decreasing digestive enzyme activity (trypsin inhibitors), causing protein precipitation (tannins), or binding to essential minerals (phytates) inside our gastrointestinal tracts. Consequently, it is important to identify, deactivate, or remove these substances from plant-based foods to ensure proper macronutrient digestion. The digestibility of plant proteins in some whole foods (like sweetcorn, chickpeas, or soybeans) may also be low because

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they are trapped in fibrous structures that cannot be broken down inside our gastrointestinal tracts. The low digestibility of plant proteins is often less of a problem when they are isolated from their natural source and used to create meat analogs. Even so, a recent Canadian study found that people who get the majority of their proteins from plant-derived sources may not be getting sufficient protein in their diet, which was mainly attributed to their relatively low digestibility and lack of some essential amino acids [33]. It is therefore important for the plant-based food industry to create products that do contain sufficient amounts of good quality proteins. Seafood, especially fatty fish, is a good source of omega-3 fatty acids that are reported to have several health benefits. Consequently, vegans and vegetarians could be lacking these healthy fats in their diets. This problem can be overcome by incorporating alternative sources of omega-3s into plant-based meat and seafood products, such as those found in flaxseed or algae. Many plant-based meats are highly processed or “ultraprocessed” foods. These products are typically characterized by high levels of food processing and additive levels, which may have adverse effects on our health. High levels of salt, sugar, saturated fat, and cholesterol have been linked to chronic conditions like hypertension, diabetes, obesity, and cardiovascular disease. Moreover, a high degree of processing can break down the natural cellular structures in plants, which leads to faster digestion and absorption of nutrients in our diet. In the case of starch, this may be undesirable because it leads to a spike in blood sugar levels, which has been linked to an increased risk of overeating, obesity, and diabetes. But in the case of proteins, vitamins, and minerals, this may be beneficial because a greater amount gets absorbed by our bodies. In the future, it will therefore be important to design plant-based foods to have appropriate nutrient profiles and digestion properties. Moreover, it is possible to create plant-based foods that are fortified with health-promoting ingredients, such as nutraceuticals, probiotics, and dietary fibers, which might make them even healthier than real meat or seafood products. As mentioned in Chap. 4, Professor Frank Hu from Harvard University has defined healthful and unhealthful plant-based diets according to their impact on human health and wellbeing. A healthful diet is rich in fruits, vegetables, whole grains, nuts, legumes, tea, and coffee, whereas an unhealthful one is rich in refined grains, potatoes, sweets, snacks, desserts, fruit juices, and sweetened beverages [34]. For all of us, whether omnivore, vegetarian, or vegan, including more fresh fruit and vegetables, whole grains, and nuts in our diets rather than highly processed foods would be better for our health. However, the most relevant question at present is what are the nutritional and health consequences of substituting real meat products with plant-based equivalents?

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Researchers at the Stanford School of Medicine addressed this question by comparing the nutritional effects of replacing real meat products with plant-­ based meat analogs [35]. They carried out a 16-week randomized crossover trial that compared the consumption of plant-based chicken, beef, and pork products to organic, animal-based versions of the same products. The participants consumed two or more servings of the products every day for 8 weeks. There was a significant improvement in cholesterol levels and body weight for the participants who consumed the plant-based meat analogs. The amounts of protein and sodium consumed were fairly similar for the two diets but the plant-based one contained more dietary fibers, phytochemicals, and less saturated fat. This study suggests that simply replacing animal-based foods with plant-based alternatives can be beneficial for your health, provided they are designed well.

Is Plant-Based Meat Safer to Eat? The impact of our diet on our health also depends on the safety of the foods we eat. Do we reduce our risk of becoming sick if we eat less meat? The chemical and microbial contaminants in plants differ from those in animals. As discussed in Chap. 5, more people become sick from eating meat than fresh fruits and vegetables, but the severity of the illness is often worse for the plant-­ based foods. This is because fresh fruits and vegetables are usually eaten raw, and so there is no thermal processing step to kill any harmful microbes on them before they are eaten. In contrast, raw meat is often contaminated with harmful microbes like salmonella or E. coli, but it is cooked before eating, which destroys them. Having said this, poor handling of raw meat before cooking is a major source of food poisoning because live bacteria can then enter our bodies. When considering the safety of plant-based foods, however, it is not fair to compare the risk of eating cooked meat with that of eating raw fruits and vegetables (which may be eaten in both meaty and meat-free diets). We should really be comparing the safety risks of equivalent products, such as real chicken and plant-based chicken. Plant-based meat analogs are usually thermally processed before they are sold to consumers, and so are not usually contaminated with the microbes found in raw meat. They should therefore present a much lower risk than preparing meals from raw meat. For precooked foods, microbiological studies tend to show that both real and plant-based meats have fairly similar safety risks [36]. They are both sources of nutrients and moisture that microbes can use to grow. However, one recent study did report a slightly higher risk for

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some kinds of plant-based meats. Researchers in Hungary compared microbial growth on meals containing either real or plant-based meat balls after they were cooked and then left in a refrigerator or at room temperature [36]. The scientists found that microbes grew faster in the plant-based meat balls than in the real ones at room temperature. But there was little difference when they were kept in the fridge, and the total numbers of microbes present were much smaller at this lower storage temperature. The researchers postulated that this may have been because the plant-based meat balls were less acidic, which meant that microbes could grow more easily. This study shows that there are food safety risks associated with eating plant-based foods and highlights the importance of storing your foods in the refrigerator when they are not eaten immediately. Don’t leave those veggie meatballs you ate as a midnight snack on the kitchen top and then eat them for breakfast the day after. There are also other potential safety risks linked to the new generation of plant-based foods. Some plant-derived ingredients can become contaminated with pesticides, fertilizers, heavy metals, mycotoxins, or alkaloids during their production, storage, and transport, which could lead to safety concerns and is still poorly understood [37, 38]. It is therefore just as important to carefully store, handle, clean, test, and prepare plant-based foods as it is animal-­ based ones. In summary, eating plant-based meat avoids some of the food safety risks associated with eating real meat (especially when preparing meals from raw meat), but it has its own safety risks that must be considered when creating the next generation of safe and healthy plant-based foods [39]. Even so, there are some big potential gains in food safety that can be obtained by reducing the amount of meat in our diet. As discussed in Chap. 5, the risks of zoonotic diseases (like COVID-19) and antimicrobial resistance could be greatly decreased if we switched to a more plant-based diet.

Is Plant-Based Meat More Ethical? One of the most important reasons that some people give for not eating meat is their ethical concerns about animal welfare and rights [40, 41]. These people believe that animals have certain rights and should therefore not be confined and killed for human food. Overall, there are almost 70 billion livestock animals killed every year for human food, with the majority of them being chickens. The way these animals are bred, raised, and killed varies greatly from farm to farm. They may be relatively free to roam about, or they may be confined to spaces so small they cannot even turn around. The animals used to

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produce meat are increasingly being raised on industrialized farms to increase production yields and reduce costs [42]. But, the practices used to increase the productivity and profitability of the food industry cause increased pain and suffering to livestock animals [42]. In addition to livestock animals, it has been reported that as many as 1 trillion fish are killed every year for human consumption, which also creates high levels of pain and suffering. There is therefore a strong argument that eating plant-based meat is more ethical than eating real meat or seafood. Many people who consume these products (including myself before I became a vegetarian) exhibit a form of cognitive dissonance – they dissociate the food on their plate from the living animal it came from. Nevertheless, this is changing as more of us become aware of the dire lives that animals must suffer to provide us with food. Overall, if we believe animals can suffer and that they have some basic rights, we should either stop eating them or at least only eat meat from animals that have been raised and killed in a more humane way. However, treating livestock animals with more kindness typically raises the cost of the meat they produce, which puts it out of reach of many consumers. Moreover, animals raised under more humane conditions often generate more greenhouse gasses and require more land and water than those raised on factory farms. Consequently, there are also ethical issues associated with equity, fairness, and sustainability linked to raising livestock animals under more humane conditions.

 ut Can Eating Plant-Based Meat Really Make B a Difference? Over the past few years, the plant-based food industry has already shown it can mass-produce meat analogs, as seen by the growing number of plant-­ based burgers, sausages, and nuggets in our supermarkets and restaurants. However, there is still a long way to go before these products make a substantial impact on our environment. The sales of plant-based meat analogs are currently an impressive $1.4 billion, but they still only make up around 1.4% of the total meat market [43]. In future, it will be critical for the plant-based meat industry to scale up its production and distribution facilities so that it can have a bigger environmental impact. This will, however, depend on whether consumers are willing to buy plant-based meat products instead of real meat ones. There are still several challenges the industry needs to overcome before this happens. They need to produce a broader range of

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plant-­based meats that consumers can choose from, including those that mimic whole muscle meats like chicken breast, beef steak, pork chops, or lamb shank. Moreover, they have to make these products more accurately mimic the desirable quality attributes of real meats, such as their meaty look, mouthfeel, and taste. Another major hurdle is cost. Plant-based meats are often considerably more expensive than the equivalent animal-based ones, which makes it difficult for many consumers to afford them. There is also a lack of accessibility to plant-based foods – they tend to be more common in high-end supermarkets and restaurants, although some fast-food restaurants have started to carry them, such as the Impossible Whopper sold at Burger King. In the future, it will be important to encourage as many people as possible to incorporate plant-based foods into their diets so as to have a significant impact on the environment and animal welfare. This may require proactive government action to promote the benefits of switching to a meatless diet.

My Takeaway There is strong evidence that eating plant-based meat rather than real meat is much better for our environment and animal welfare. There is some evidence that eating plant-based meat can be better for our health, provided we plan our diets carefully. If we are going to replace real meat and seafood products with plant-based alternatives, then we should choose products that have similar or better nutritional profiles. As mentioned earlier, many of the current generation of plant-based foods have worse nutritional profiles than the animal-­based ones they are designed to replace. It is therefore critical for the plant-based food industry to carefully design the nutrient composition, digestibility, and bioavailability of their products so that they provide more health benefits than eating meat. Of all the alternative protein sources considered in this book, plant-based meats have the most potential for reducing the negative environmental impacts of the food industry in the short term. Consumer concerns about this issue were one of the main reasons for the boom in the plant-based food industry from the mid-2010s to the early 2020s. Extensive media coverage made many people concerned about the adverse effects of eating meat and seafood on the environment, as well as the ethical issues linked to livestock production, and the potential health concerns with eating meat. They were therefore willing to give plant-based meat analogs a try. However, surveys consistently show that the most important factors impacting consumer choice

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are taste and cost. Many consumers are unwilling to pay a much higher price for a plant-based meat product that does not taste as good as the real thing, especially in challenging economic times when money is tight. This reluctance may account for the cooling off of the plant-based food sector recently, after half a decade of rapid growth. In the future, it will be important to create plant-based meat and seafood products that are delicious, affordable, and nutritious, as well as being good for the environment and animal welfare. Moreover, it will be important to create a more varied portfolio of plant-based products, such as chicken breast, beef steak, and pork chop analogs, to meet consumer demands for a more diverse range of eating experiences.

References 1. Toldra, F., Lawrie’s Meat Science. 8th Edition ed. 2017, Cambridge, UK: Woodhead Publishing. 2. Lillford, P.J., The impact of food structure on taste and digestibility. Food & Function, 2016. 7(10): p. 4131-4136. 3. Tornberg, E., Engineering processes in meat products and how they influence their biophysical properties. Meat Science, 2013. 95(4): p. 871-878. 4. Tornberg, E., et  al., The texture of comminuted meat products. Food Australia, 2000. 52(11): p. 519-524. 5. Ertbjerg, P. and E. Puolanne, Muscle structure, sarcomere length and influences on meat quality: A review. Meat Science, 2017. 132: p. 139-152. 6. Bertram, H.C., et al., NMR relaxometry and differential scanning calorimetry during meat cooking. Meat Science, 2006. 74(4): p. 684-689. 7. Lepetit, J., Collagen contribution to meat toughness: Theoretical aspects. Meat Science, 2008. 80(4): p. 960-967. 8. Purslow, P.P., Contribution of collagen and connective tissue to cooked meat toughness; some paradigms reviewed. Meat Science, 2018. 144: p. 127-134. 9. Hausman, G.J., et al., The history of adipocyte and adipose tissue research in meat animals. Journal of Animal Science, 2018. 96(2): p. 473-486. 10. Stern, J.H., J.M.  Rutkowski, and P.E.  Scherer, Adiponectin, Leptin, and Fatty Acids in the Maintenance of Metabolic Homeostasis through Adipose Tissue Crosstalk. Cell Metabolism, 2016. 23(5): p. 770-784. 11. Urrutia, O., L. Alfonso, and J.A. Mendizabal, Cellularity Description of Adipose Depots in Domesticated Animals, in Adipose Tissue, L. Szablewski, Editor. 2018, InTechOpen: On Line. p. 1–15. 12. Joachim, D. and A. Schloss. The Science of Grilling Burgers. Fine Cooking (Issue 118) 2018; Available from: http://www.finecooking.com/article/ the-­science-­of-­grilling-­burgers.

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13. Loveday, S.M., Plant protein ingredients with food functionality potential. Nutrition Bulletin, 2020. 45(3): p. 321–327. 14. Loveday, S.M., Food Proteins: Technological, Nutritional, and Sustainability Attributes of Traditional and Emerging Proteins, in Annual Review of Food Science and Technology, Vol 10, M.P.  Doyle and D.J.  McClements, Editors. 2019. p. 311–339. 15. Hemler, E.C. and F.B. Hu, Plant-Based Diets for Cardiovascular Disease Prevention: All Plant Foods Are Not Created Equal. Current Atherosclerosis Reports, 2019. 21(5). 16. Astrup, A., et al., Saturated Fats and Health: A Reassessment and Proposal for Food-­ Based Recommendations JACC State-of-the-Art Review. Journal of the American College of Cardiology, 2020. 76(7): p. 844–857. 17. Saini, R.K. and Y.S.  Keum, Omega-3 and omega-6 polyunsaturated fatty acids: Dietary sources, metabolism, and significance – A review. Life Sciences, 2018. 203: p. 255–267. 18. Shahidi, F. and P. Ambigaipalan, Omega-3 Polyunsaturated Fatty Acids and Their Health Benefits, in Annual Review of Food Science and Technology, Vol 9, M.P. Doyle and T.R. Klaenhammer, Editors. 2018. p. 345–381. 19. Arab-Tehrany, E., et al., Beneficial effects and oxidative stability of omega-3 long-­ chain polyunsaturated fatty acids. Trends in Food Science & Technology, 2012. 25(1): p. 24–33. 20. Nogueira, M.S., et al., Oxidation products from omega-3 and omega-6 fatty acids during a simulated shelf life of edible oils. Lwt-Food Science and Technology, 2019. 101: p. 113–122. 21. Sha, L. and Y.L.L. Xiong, Plant protein-based alternatives of reconstructed meat: Science, technology, and challenges. Trends in Food Science & Technology, 2020. 102: p. 51–61. 22. Schreuders, F.K.G., et al., Comparing structuring potential of pea and soy protein with gluten for meat analogue preparation. Journal of Food Engineering, 2019. 261: p. 32–39. 23. McClements, D.J. and L. Grossmassn, Next-Generation Plant-based Foods: Design, Production, and Properties: Plant-based foods. 2022, New York, NY, USA: Springer Scientific. 24. Zacharias, N. and G. Stone, Eat for the Planet: Saving the World One Bite at a Time. 2018, New York, NY: Abrams. 25. GFI, Plant-based meat for a growing world. 2020, Good Food Institute: Washington, D.C. 26. Hayek, M.N., et al., The carbon opportunity cost of animal-sourced food production on land. Nature Sustainability, 2021. 4(1): p. 21–24. 27. Chang, J., et al., Climate warming from managed grasslands cancels the cooling effect of carbon sinks in sparsely grazed and natural grasslands. Nature Communications, 2021. 12(1): p. 118. 28. Howard, P., The Politics of Protein. 2022, IPES-Food: Brussels, Belgium.

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29. Wolk, A., Potential health hazards of eating red meat. Journal of Internal Medicine, 2017. 281(2): p. 106–122. 30. Possidonio, C., et al., Consumer perceptions of conventional and alternative protein sources: A mixed-methods approach with meal and product framing. Appetite, 2021. 156. 31. Gorissen, S.H.M., et al., Protein content and amino acid composition of commercially available plant-based protein isolates. Amino Acids, 2018. 50(12): p. 1685–1695. 32. Sarwar Gilani, G., C.  Wu Xiao, and K.A.  Cockell, Impact of Antinutritional Factors in Food Proteins on the Digestibility of Protein and the Bioavailability of Amino Acids and on Protein Quality. British Journal of Nutrition, 2012. 108(S2): p. S315–S332. 33. Marinangeli, C.P.F., et al., The effect of increasing intakes of plant protein on the protein quality of Canadian diets. Applied Physiology, Nutrition, and Metabolism, 2021. 46(7): p. 771–780. 34. Hu, F.B., B.O.  Otis, and G.  McCarthy, Can Plant-Based Meat Alternatives Be Part of a Healthy and Sustainable Diet? Jama-Journal of the American Medical Association, 2019. 322(16): p. 1547–1548. 35. Crimarco, A., et al., A randomized crossover trial on the effect of plant-based compared with animal-based meat on trimethylamine-N-oxide and cardiovascular disease risk factors in generally healthy adults: Study With Appetizing Plantfood- Meat Eating Alternative Trial (SWAP-MEAT). American Journal of Clinical Nutrition, 2020. 112(5): p. 1188–1199. 36. Toth, A.J., et  al., Microbial Spoilage of Plant-Based Meat Analogues. Applied Sciences-Basel, 2021. 11(18). 37. Alshannaq, A. and J.H. Yu, Occurrence, Toxicity, and Analysis of Major Mycotoxins in Food. International Journal of Environmental Research and Public Health, 2017. 14(6). 38. Mihalache, O.A., L. Dellafiora, and C. Dall’Asta, A systematic review of natural toxins occurrence in plant commodities used for plant-based meat alternatives production. Food Research International, 2022. 158. 39. Caldwell, J.M., How Safe Are Plant-Based Meat Alternatives? Food Technology, 2021. 75(1): p. 52–55. 40. Alvaro, C., Ethical Veganism, Virtue, and Greatness of the Soul. Journal of Agricultural & Environmental Ethics, 2017. 30(6): p. 765–781. 41. Ursin, L., The Ethics of the Meat Paradox. Environmental Ethics, 2016. 38(2): p. 131–144. 42. Rossi, J. and S.A. Garner, Industrial Farm Animal Production: A Comprehensive Moral Critique. Journal of Agricultural & Environmental Ethics, 2014. 27(3): p. 479–522. 43. GFI, State of the Industry Report: Plant-Based Meat, Eggs, and Dairy. 2021, Good Food Institute: Washington, D.C. p. 1–85.

7 Biotech Meat: Growing Meat from Cells

Abstract  This chapter shows how the latest advances in biotechnology are being used to create a new generation of meat alternatives, including cultured animal cells, cultured microbial cells, and precision fermentation products. Cultured animal cells are grown in large bioreactors under controlled nutrient, growth factor, and environmental conditions. The cells used are taken from cows, pigs, chickens, and fish, without having to kill any animals, thereby reducing many of the negative impacts of using animals for food. Meat alternatives can also be grown from microbial cells (such as microfungi or bacteria) in bioreactors. The mycoprotein known as Quorn is a successful example of this technology. Recently, some companies have used this approach to create meat analogs from air and sunlight, which use microbes to create proteins from the carbon dioxide and water in air powdered by solar energy. The utilization of precision fermentation to produce milk, egg, or meat proteins that have never been inside an animal is also highlighted, as well as the application of this technology to produce other ingredients useful for application in meat analogs, such as flavors, colors, and preservatives. The potential of these new technologies to compete with the meat industry is highlighted. Keywords  Cultured meat • Microbial meat • Mycoprotein • Precision fermentation • Genetic engineering Our world is built on biology and once we begin to understand it, it then becomes a technology. Ryan Bethencourt

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 D. J. McClements, Meat Less: The Next Food Revolution, Copernicus Books, https://doi.org/10.1007/978-3-031-23961-8_7

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Should We Believe the Hype? One of the most hyped areas of the alternative protein space is cellular agriculture – using cells to produce foods. This is not my own research field, and so when I started writing this book, I only had a limited understanding of the science and technology behind it. I therefore decided to dig into the field of cellular agriculture more deeply and find out what all the hype was about and if it really could contribute to the creation of a more sustainable and healthy food supply. Some of the questions I wanted to answer were: how is this kind of food created? Can it be produced affordably in sufficiently large quantities to impact global meat consumption? Is it healthy? Is it really more environmentally friendly than meat?

The Biotech Revolution The past few decades have seen a revolution in biotechnology that is transforming all of our lives. One of the most successful early applications of this technology was to produce insulin for diabetics, but more recently it has also been used to create the vaccines that have been so successful at combating coronavirus. Biotechnology is also playing an important role in the creation of meat alternatives that look and taste like the real thing. As its name suggests, biotechnology is technology based on biology. It uses cells, which may come from microbes, animals, plants, or even insects, to create industrial processes and products that are useful to humankind. Although our scientific understanding of biotechnology has advanced rapidly over the past century, we have actually been using it for thousands of years to create foods like bread, cheese, beer, and wine. These products are formed when certain kinds of microbes (yeasts, bacteria, and molds) ferment foods, such as wheat, milk, oats, and fruit. In this chapter, I look at some of the innovative ways biotech is being used to create meat alternatives. Collectively, these approaches are known as cellular agriculture because they use cells to grow foods. There are currently three main approaches to producing meat analogs using cellular agriculture: cultured animal cells, cultured microbial cells, and precision fermentation. These biotech methods can be compared to traditional farming practices. Livestock animals themselves can be consumed as meat (like beef, lamb, pork, or chicken), or they can be used to produce substances that we eat (like milk and eggs). Similarly, we can eat cells (which may come from animals or microbes) or we can use the cells to produce substances that we eat

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(like proteins, fats, vitamins, colors, or flavors). Cultured animal and microbial cells fall into the first category, whereas precision fermentation falls into the second category.

Cultured Animal Cells: Clean Meat In the second book of Douglas Adams’ Hitchhiker’s Guide to the Galaxy, The Restaurant at the End of the Universe, we are introduced to a cow specially bred to want to be eaten. It can even talk and happily points out the tastiest parts of its body to the diners. We are not at that stage yet, but we are certainly getting closer. Imagine ordering a dish that looks, feels, and tastes like beef but has never been inside a cow’s body. Instead, the meat cells have been grown in a large fermentation tank, just like beer. You can already do this. If you live in Singapore, or can afford to travel there, there is a restaurant that already sells this kind of cultured meat (albeit at a high price). Biotechnology companies around the globe are trying to create similar products and bring them to the market in the near future, including cultured beef, chicken, lamb, pork, and seafood products. Soon, we may all be able to buy cultured meat as an alternative to real meat grown inside an animal that is then slaughtered. Because it is made from real animal cells, this kind of meat can closely match the look, feel, and taste of real meat. Moreover, very few animals are required to provide these cells, which alleviates animal welfare concerns and environmental problems associated with the livestock industry.

How Is Cultured Meat Made? Chicken, pork, beef, or fish can be grown in bioreactors (fermentation tanks like those used to produce beer) from living cells taken from animals, without having to slaughter them [1]. In principle, all the cells that comprise real meat, like those in muscle, connective, and adipose tissues, can be grown in fermentation tanks to create foods with similar properties as real meat. The production of meat using this kind of biotechnology has greatly benefited from advances made by biomedical researchers trying to create artificial organs to replace defective ones in humans. The methods used to create artificial hearts, livers, or kidneys for human transplants can also be used to create artificial meat for human consumption. Indeed, it is much simpler to create a tasty piece of artificial meat that has to last for a few days or weeks before it is eaten than it is to create an artificial heart that may have to function inside

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Fig. 7.1  Cultured meat is grown by removing the cells from a live animal and then growing them under carefully controlled conditions in a series of fermentation tanks. The cells are then encouraged to cluster together into muscle-like shapes. (Picture kindly supplied by the Good Food Institute. Image Credits: SuperMeat, New Age Meats, and Wildtype)

somebody for decades. One of the reasons for the recent increase in the number of companies producing cultured meat may be because the medical applications of artificial organs have not yet been realized, and so biomedical scientists have sought new applications for their hard-earned skills. Cultured meat is produced in several stages (Fig. 7.1) [2]. During the collection stage, several cells are taken from an animal using a simple procedure that does not harm or hurt it, like the biopsies used to collect human cells in a doctor’s office. Some of these cells are then selected and grown in a suitable environment to create a bank of donor cells. These cells undergo a process known as immortalization, so they can be used to produce meat indefinitely, without having to keep collecting new cells from animals. In the proliferation stage, a group of donor cells is taken from the cell bank and mixed with a carefully formulated broth that contains the nutrients and growth factors the animal cells need to grow and proliferate. This mixture is then placed inside a bioreactor, which consists of a closed tank that controls the cell’s environment to promote their proliferation (Fig. 7.2). The temperature, oxygen levels, and pH the cells experience are closely monitored and controlled during this stage. At the end of the proliferation stage there may be trillions of cells in the bioreactor. In the maturation stage, the cells are placed into a different kind of bioreactor, which causes them to transform into the required cell type, such as muscle, connective tissue, or adipose cells. This is achieved by adding specific additives to the bioreactor, like growth factors and nutrients. In addition, “scaffolds” may be added to encourage the cells to form clumps with sizes and shapes resembling the muscle fibers or adipose tissue found in real meat. After about 4 to 6 weeks, the cells can be harvested from the bioreactor and used to

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Fig. 7.2  Bioreactors (fermentation tanks) used to produce cultured meat at the UPSIDE Foods facility. (Image kindly provided by UPSIDE Foods)

Fig. 7.3  Cultured meat products created in bioreactors from real animal cells by UPSIDE Foods: meat balls and chicken salad. (Images kindly provided by UPSIDE Foods)

create cultured meat products, like meatballs, beef burgers, or chicken nuggets (Fig. 7.3). Teams of scientists around the globe have been working over the past decade or so to find the most suitable cells, nutrients, growth factors, bioreactor conditions, and scaffolds needed to successfully grow cultured meat. These efforts seem to be finally reaping rewards, with numerous companies reporting that they expect to have commercial products on the market in the next few years.

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A Brief History of Cultured Meat The idea of growing meat outside of animals is not a new one. In 1931, Winston Churchill wrote an essay in Strand Magazine titled “Fifty Years Hence” where he stated, “We shall escape the absurdity of growing a whole chicken in order to eat the breast or wing, by growing these parts separately under a suitable medium.” His prediction did not come true in the timeframe he envisioned. In 1981, we were still a long way from creating cultured chicken. More recently, however, the work of several pioneering scientists has made cultured meat a reality. Some of the earliest research on the creation of cultured meat (actually fish) was carried out by NASA scientists in the 1990s. These scientists were trying to create nutritious foods that astronauts could grow onboard their spaceships during long-haul space voyages, like a trip to Mars and back. In the mid-­2000s, Professor Mark Post from Maastricht University secured funding from the Dutch government to grow cultured meat. His research resulted in the creation of the first cultured meat burger, which has been estimated to have cost over $330,000 to produce [2]. Speaking as a research scientist this price tag is a bargain – a typical research grant is over half a million dollars and often very little is found. Since then, Post and his team have managed to reduce the cost of producing cultured meat dramatically, to a point where it is starting to become commercially viable. Indeed, he has co-founded a company in the Netherlands known as Mosa Meat, whose stated aim is to create a beef burger that is kinder to the environment, animals, and our health. Post serves as the Chief Scientific Officer of the company, while keeping his academic position as a Professor of Sustainable Industrial Tissue Engineering at Maastricht University. One of the other co-founders is Peter Verstrate, a food technologist, who worked in the traditional processed meat industry for years before helping to found the company. His expertise with real meat is likely to be extremely valuable for fostering the development of cultured meat. Mosa Meat take cells from Limousin cows, a French breed of beef cattle, and grow them into muscle and fat cells that are then mixed together to form beef burgers. On their website, Mosa Meat claim “They don’t taste ‘just like’ meat. They are real meat. Real beef that oozes and sizzles with real fats and juices” (mosameat. com). The Dutch government continues to stimulate innovation in food biotechnology in the Netherlands, investing another $60 million in research into cellular agriculture in 2022. This highlights the potential they see for these new technologies in transforming the way we produce our foods in the future. Mosa Meat has also attracted tens of millions of dollars of funding from

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investors and individuals concerned about the harmful effects of the livestock industry on our environment, including Sergey Brin the co-founder of Google and Leonardo DiCaprio the American film star. There are now dozens of companies around the globe developing cultured meat products. However, there are several hurdles that must be overcome before these products are ready for widespread sale, including their high costs, the need to scale up their production, and the fact that it is still not legally permitted to sell cultured meat as food in most countries. When it does receive regulatory approval, it is likely that high-end restaurants will be the first target of these companies because their products can be sold at a higher cost. As mentioned earlier, the first cultured meat product ever sold to a consumer was a chicken bao in a restaurant in Singapore (“1880”), where the government gave regulatory approval to this futuristic food in 2020. This product was produced by Good Meat, a spin-off of Eat Just, a Californian company that makes both plant-based foods and cultured meat. Eat Just has a promotional video of its staff eating chicken nuggets at a company picnic, while the chicken (“Ian”) whose cells were used to grow the nuggets wanders around the picnic table (www.justforall.com). For the mass market, the initial offerings of cultured meat are most likely to be designed to mimic real meat products with fairly simple structures, like hamburgers, nuggets, and sausages. As the technology required to assemble the living cells into more complex structures develops, we will see products like cultured beef steaks, chicken breasts, and pork chops enter the market. Another leader in the field of cultured meat in the United States is UPSIDE Foods, formerly known as Memphis Meats. This company was co-founded by Dr. Uma Valeti, who gave up his job as a cardiologist to become a food innovator and entrepreneur. He was brought up in India where his father was a veterinarian and his mother was a physics teacher, so he had been exposed to science and biology from an early age. Valeti talks about a formative experience he had when he was a child in India [3]. He was at his friend’s birthday party where they were serving delicious, curried goat and chicken tandoori dishes at the front of the house. When he wandered around the back of the house, Valeti was shocked to see the cooks decapitating and gutting the animals they were feeding to the party goers. Although he did not become a vegetarian until several years later, this experience had a profound effect on him and would be one of the driving forces for his passion for creating kinder alternatives to meat. After moving to America, Valeti trained to be a medical doctor specializing in cardiology. While working at the Mayo Clinic he helped to develop a pioneering method of using stem cells to repair heart tissue damaged after a cardiac arrest. If stem cells could be used to grow heart muscles in

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humans, Valeti pondered, why couldn’t they also be used to grow meat products? He then had a vision that changed his life. If he continued to work as a cardiologist he might save a few thousand lives throughout his career, but if he could create a new generation of healthier and more ethical meat products, he could save billions of human lives and trillions of animal lives. In 2014, Valeti was introduced to Nicholas Genovese, who had trained in cell biology and tissue engineering. Genovese had also been using stem cells to create replacement organs for humans, but he had been using a 3D printer to construct these organs from living cells. Valeti and Genovese started their own business with the modest goal of changing the world. In 2015, the two men moved to the Bay Area in California, a favorite spot for cellular agriculture companies, and managed to secure their first funding to support the new company. Within a few months they were already producing tiny meatballs from muscle and connective tissues produced by culturing animal cells. In the documentary Meat the Future, the scientists at UPSIDE Foods are shown keeping a white board where they record the change in the costs of producing cultured meat. This number has decreased dramatically over the past few years and is finally reaching a value that is becoming economically viable. UPSIDE has raised over $600 million since its inception, as is currently worth over a billion dollars, without having sold a single product. It is using this funding to reduce the costs and scale up its process of creating cultured meat. Recently, it opened an innovation center and state-of-the-art pilot-scale factory capable of producing 400,000 pounds of cultivated meat per year. This may seem like a lot, but it is less than 0.001% of the total amount of meat annually consumed in the United States. In other words, UPSIDE would have to build more than a hundred thousand similar factories to meet the current demand for meat by American consumers. Clearly, there is a long way to go, but you have to start somewhere. Valeti and his team are working to produce a range of meat-like products, with an initial focus on chicken. The legal team at UPSIDE are working with regulators in the US government to ensure their products can be sold to consumers when they are ready to go to market, while the marketing team is educating consumers about the potential benefits of this futuristic alternative to meat. Will consumers accept meat grown in a laboratory? I am a vegetarian and still have reservations about eating cultivated meat, even though it is more environmentally friendly and ethical. But I am certainly open to persuasion.

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Better than Real Meat? If people are going to be persuaded to eat meat grown in a bioreactor rather than in an animal, there must be some compelling reasons. Studies have shown that cultured meat is more sustainable, environmentally friendly, safer, and ethical than real meat [1]. It can be produced under sanitary conditions in large factories that look like breweries, rather than in dirty farms and slaughterhouses, and so there is no need for antibiotic treatments and a much lower risk of microbial contamination, thereby reducing the risk of food poisoning. A Guardian newspaper article on the meat industry reported that dirty or spoiled meat was coming into contact with the rest of the meat on the production lines, leading to cross-contamination. In one unforgettable quote from this article, it was stated that “meat destined for the human food chain found riddled with fecal matter and abscesses filled with pus.” Obviously, these kinds of issues would not arise during the production of cultured meat because the cells used do not have anuses or pustules. Another advantage of cultured meat over real meat is that it does not need to be fed with huge amounts of grains or grasses, thereby freeing up land that is currently used to produce feed for livestock. Cell cultures do not need to maintain their body temperatures, move around, or grow brains, bones, skin, and cartilage. As a result, they need much less energy and resources to produce a given amount of food than livestock animals. Indeed, studies show that cultured meat requires much less land, freshwater, energy, and other inputs than conventional livestock, while generating less greenhouse gasses and other forms of pollution [4, 5]. Even so, the production of cultured meat does require more fossil fuels than the production of insect- or plant-based foods, which is mainly due to the large amounts of energy needed to maintain the cell cultures in the fermentation tanks [6]. However, this issue may become less important as the industry expands and the technology advances. In many countries, the livestock industry is one of the main users of antibiotics, which is contributing to the alarming rise in antibiotic resistance discussed earlier (Chap. 5). Cultured meat does not use these antibiotics and so may help to alleviate this problem. Finally, because cultured meat does not require the wholesale raising, confinement, and slaughtering of animals, it is much more ethical than real meat and is less likely to promote the rise of zoonotic diseases, like coronavirus, bird flu, or swine flu. Cultured meat also has some advantages over other kinds of meat alternatives, like plant-based meat analogs. It is much easier to simulate the look, feel, and taste of real meat using animal cells than using plant-based

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ingredients. As a result, meat lovers are more likely to prefer eating cultured meat than plant-based meat. Moreover, cultured meat is made from the same cells as real meat and so it contains similar nutrients, like proteins, fats, vitamins, and minerals. Switching from real meat to cultured meat should therefore not cause any major changes in human nutrition and health. In fact, we may even be able to design cultured meat to be healthier than the real thing by programing cells to produce healthier nutrients (like more unsaturated fats and less saturated ones). However, this would require some genetic manipulation of the animal cells, which would not be acceptable to all consumers.

Making Cultured Meat a Reality Given its enormous potential to transform the way we eat, how long will it be before we can buy cultured meat in our supermarkets and restaurants? Producing meat by cultivating a few cells taken from a living animal is a revolutionary idea. It is something that has never been done before on a large scale. Not surprisingly, there have therefore been several technical challenges that the cultured meat industry has had to address. One of the biggest of these has been the need to find a suitable broth to nourish and grow the cells. Some of the most important nutrients and growth factors in traditional tissue engineering broths come from animals. The most alarming one for a vegan or vegetarian is fetal bovine serum, which is extracted from the blood of fetuses cut from the wombs of cows slaughtered during milk or meat production [7]. Any ethical advantages that cultured meat has over traditional meat are lost when it requires fetal bovine serum to produce it. Fetal bovine serum contains a unique cocktail of substances whose purpose in nature is to stimulate the growth of cells during an animal’s early development. Biotechnologists have worked for over a decade to create animal-free alternatives to bovine fetal serum. Several cultured meat companies claim to have made major breakthroughs in this area and are now able to create broths that do not require bovine fetal serum or any other animal derivatives, including Mosa Meats and UPSIDE Foods. Another major challenge is to ensure that the large bioreactors and factories used to produce cultured meat do not become contaminated with undesirable microbes, because this would lead to economic losses and health risks. When I visited another food factory that uses bioreactors to produce foods from cells, I saw the great efforts the company made to ensure the facilities remained sterile throughout the entire process. High-temperature pressurized steam was forced through all the production equipment to kill any contaminating

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microbes that might be present. Currently, the production capacity of the cultured meat industry is miniscule compared to that of the traditional meat industry, and so it will be critical that its production facilities are massively scaled up in the future to meet the growing global demand for meat. It will also be important to reduce the cost of cultured meat, so it is not too expensive for the average consumer and only an option for the elite. The final challenge is regulatory approval. Cultured meat is currently not legally acceptable for consumption in most countries (with the exception of Singapore). For this reason, cultured meat companies are working closely with government regulators to show that their products are safe. It is likely that the US government will approve cultured meat for human consumption in the near future. There are currently some heated debates about whether these challenges can ever be overcome so that cultured meat will become a commercial reality that can compete with the real meat industry. Nobody is disputing that meat-­ like products can be produced in small batches using this technology, but can it be done at the scale and cost that will make it commercially viable? The Good Food Institute, a nonprofit organization in Washington DC that promotes alternative proteins, is optimistic and believes that the price of cultured meat will come down dramatically over the next decade to a level that will make it competitive. Based on a techno-economic assessment of cultured meat production they commissioned, they predict that the cost will fall from around $10,000 per pound of cultured meat now to less than $2.60 per pound in 2030, which would make it competitive with real meat. This prediction is based on the industry overcoming various hurdles to mass production, with the most important one being reducing the cost of the growth media. In contrast, other scientists are highly skeptical and doubt that cultured meat can ever be produced on a commercial scale that will impact current meat consumption significantly [8]. David Humbird, a UC Berkeley-trained chemical engineer, was commissioned to carry out a different techno-economic assessment on the feasibility of producing cultured meat. He reported that producing cultured meat is plagued with technical challenges that are extremely difficult to overcome, including the high costs of equipment and ingredients and the fragility of mammalian cells, which severely limit the large-scale economic production of meat alternatives [9, 10]. Based on these techno-economic assessments, it has been estimated that to build a new factory capable of producing around 22 million pounds of meat per year would cost around $450 million. This might seem like a lot of meat, but it is a tiny fraction (less than 0.02%) of the 100 billion pounds of meat produced in the United States every year. To produce just 10% of the meat

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Fig. 7.4  Examples of different kinds of cultured meat and seafood products being created from different companies around the world, including Wild Type, Avant Meats, New Age Meats, Shiok Meats, and BlueNalu. (Image kindly supplied by the Good Food Institute (Creative Commons))

consumed today would therefore require around 500 of these factories in the United States alone, which would cost a staggering $225 billion. And that is only the cost of the production facilities – before any cultured meat has actually been produced. If we extended this to the whole world, we would need almost ten times the number of factories, which would cost around two trillion dollars. Despite these challenges, some of the major players in the meat industry, including Tyson and Cargill, have already invested large sums of money in cultured meat companies, which suggests they do see a future in this more sustainable source of protein. They are betting that the numerous scientists and engineers working to make cultured meat a reality will come up with creative solutions to the existing technical challenges, which will bring down the costs of large-scale production. If they can do this, then the traditional meat industry already has the processing and distribution facilities needed to handle huge quantities of meat. Many of these facilities could be repurposed to handle cultured meat, therefore facilitating the transition to a more healthy, sustainable, and ethical food supply. Moreover, there are many companies working around the globe to make this technology a reality, who are producing more and more delicious-looking cultured meat foods (Fig. 7.4).

Cultured Bug Meat In the summer of 2022, the US National Academy of Sciences organized a meeting on alternative sources of food proteins. Professor David Kaplan from Tufts University in Massachusetts gave a thought-provoking and

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gut-wrenching presentation about his pioneering work in developing cultured meat. David is producing meat from animal cells, but he is also exploring the potential of using insect cells for this purpose. From a consumer acceptance point of view this would appear to be extremely audacious. Many consumers don’t want to eat insects and they don’t want to eat meat grown in a laboratory. So, combining these two approaches wouldn’t seem to be very promising. However, David has good reasons for pursuing his goal of creating cultured bug meat. The use of insect cells can overcome many of the challenges of economically growing mammalian cells on the vast scales needed to compete with the meat industry. Insect cells are much more robust, cheaper, and easier to grow than mammalian cells, which makes them much more economically viable. Researchers have used cells from moths, caterpillars, and fruit flies for this purpose. If David’s research comes to fruition, we will all be able to buy a range of delicious and sustainable burgers, sausages, and nuggets that have been grown from insect cells. David recently received funding from NASA to develop the technology so that astronauts can create cell cultured bug meat aboard long-haul space missions. This kind of insect meat is just as healthy, if not healthier, than real meat because it contains a good balance of proteins, fats, vitamins, minerals, and dietary fibers.

Celebrity Meat and Cannibal Burgers Growing meat in a laboratory, rather than an animal, seems like something from a sci-fi movie. In the future, it could become something more like a horror movie. Would you eat the flesh of somebody? Cannibalism is extremely rare in modern society and the few stories where we do hear about it happening today tend to be when people are stranded in some isolated place with no food. In principle, the same technology used to create cultured meat from animals could also be used to create it from human cells. A few cells could be collected from a living or recently deceased person using a biopsy and then grown into meat using biotechnology. This would certainly be unacceptable to consumers and government regulators, but it could lead to some interesting and macabre food experiences. Cells could be cultured from our favorite stars from the sports, movie, music, or social media world and then turned into celebrity meat. A cinema might then sell Tom Cruise burgers during the showing of the latest installment in the Mission Impossible franchise, whereas a music venue might sell Snoop Dogg hot dogs at the rapper’s latest concert. This idea of eating food made from people’s cells might seem repulsive to most of us, but it is the same feeling that many vegans have about eating food made

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from animal’s cells. A potential solution to this problem might be for vegans to grow some of their own cells in bioreactors so they could eat meat without any animals being harmed.

Cultured Microbial Cells: Microbial Meat Rather than using biotechnology to grow mammalian cells as food, like those taken from cows, pigs, or chickens, it can also be used to grow microbial cells as food, such as bacteria, microfungi, or microalgae cells. In this case, edible microbial cells are grown in large bioreactors and then harvested and converted into meat-like food products. Under the right conditions, microbes multiply extremely quickly, which means this is a highly efficient way of producing food. Although the evolutionary pathway leading to mammalian cells diverged from that leading to microbes over a billion years ago, these two types of cells still have much in common from a nutritional perspective. They both contain proteins, fats, carbohydrates, vitamins, and minerals. Consequently, many kinds of edible microbes can fulfill our nutritional needs, just as well as meat.

A Fortuitous Tour In the summer of 2022, I traveled back to England to visit my family for the first time since the coronavirus pandemic began. While hiking along the beautiful North Yorkshire coastline with my brother Guy, I mentioned to him that I would love to visit one of the original microbial meat companies, Quorn, which I knew was located in northeast England. Quorn creates a meat-like substance known as mycoprotein by growing microfungi in bioreactors. My brother said his sister-in-law Jo worked for Quorn and she might be able to set up a visit for me. I contacted Jo the day before we flew back to the United States, fully expecting I had left it too late. Surprisingly, she managed to quickly arrange a visit for me to the Quorn production facilities in Billingham, which is actually the town where I grew up. The production facilities are located on an industrial estate in Billingham where many of my family had worked in the past. Indeed, when I was at University, I had worked nightshift in a crisp (potato chip) factory there myself during my summer holidays. This is one of the reasons I became an academic – the late nights and hot greasy working conditions put me off getting a job in a food production factory.

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Unusually, we had had a hot cloudless week in England during the whole of our vacation, but the day I visited Quorn the weather had turned and reminded me of the summers of my youth. Heavy grey clouds ladened the sky and there was the constant threat of rain. The landscape gave off post-­ apocalyptic Blade Runner vibes – gray chimneys and cooling towers gushing out white and yellowish fumes. When I was younger, I always found this scene ugly and depressing, but as I grew older, I started to appreciate the beauty of turning base elements into the things that make our modern existence comfortable and enjoyable, like fertilizers, medicines, plastics, and textiles.

Producing Microbial Meat After completing the numerous security forms at the gate to the production facilities, I was met by Steve Finn the factory manager (Fig. 7.5). Like many people in northeast England, Steve was an extremely warm, friendly, and down-to-earth person. He had worked as a biotechnologist in the medical profession for several years before turning his skills to producing sustainable foods. He kindly took time from his busy schedule to explain the Quorn production process and give me a guided tour of the manufacturing facilities. We started the tour in Steve’s office, where we sat in front of a computer that

Fig. 7.5  Factory manager Steve Finn (left) and the author (right) at the Quorn production facilities in Billingham, Cleveland, United Kingdom. In the background is the ten-story building holding one of the bioreactors (shown exposed in the right picture) used to grow the microfungi cells. (Image of bioreactor kindly provided by Steve Finn of Quorn)

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allowed him to monitor and run the entire factory from his desk. There was a representation of the Quorn production process on the screen, dotted with constantly flickering numbers. These numbers represented key parameters impacting the production of the mycoprotein, like temperature, pressure, oxygen, and nutrient levels. Here, Steve could keep an eye on the entire process to make sure everything was running smoothly. If there were any problems, he and his team could quickly detect and resolve them – often by simply pressing the touch screen on his computer. Steve was clearly proud of the work Quorn was doing to create a more sustainable food supply, as well of the vision of its founders. As early as the 1960s, scientists were predicting there would not be sufficient protein produced using conventional livestock methods to feed the growing global population. Lord Joseph Rank worked at Rank Hovis McDougall (RHM), one of the most famous food companies in the United Kingdom, which specialized in the production of flour and bread. He realized the company was producing large amounts of starch as a byproduct that was being thrown away. He therefore initiated a pioneering “Starch to Protein” project, whose aim was to convert starch into a delicious, nutritious, and safe protein-rich food. The scientists from RHM scoured the earth to find microbes that could carry out this conversion. They tested more than 3000 soil samples collected from around the globe and eventually settled on a microfungus known as Fusarium venenatum, which was discovered in a garden in the town of Marlow in the south of England. This microfungus was found to efficiently convert starch into mycoprotein. Over the next 20 years, the company carried out research and development to optimize the mycoprotein production process. Eventually, the RHM scientists successfully created a protein-rich product but they did not have the expertise needed to scale it up and commercialize it. They therefore partnered with another famous British company, Imperial Chemical Industries (ICI), in the early 1980s to form Marlow Foods. Many of my family worked at ICI and I could see their chemical production facilities from the window of the house where I grew up. In 1985, the mycoprotein produced by Marlow Foods was approved for human consumption by the UK government. At the time, the company claimed that their product was the “first new food since the potato.” The commercial production and sale of meat analogs, which were marketed under the brand name Quorn, began soon after. Later, Quorn was approved for consumption by other countries, including the United States in 2002. Clearly, Lord Rank was a pioneering individual who was well ahead of his time. Many start-­up companies today are still trying to convert waste products into protein-­rich meat analogs to improve the health and sustainability of the

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modern food supply. In America, my family and I often buy Quorn patties or nuggets from our local supermarket. Steve told me these were all made in the manufacturing facility in Billingham, which made me proud of my small industrial hometown. After donning a bright orange jacket, white hard hat, and safety goggles, Steve gave me a tour of the production facilities used to create Quorn, and explained the various processes involved. Initially, a small quantity of powdered microfungi is sprinkled into a few cups of nutrient broth, which contains the sugars and salts the microbes need to grow. The resulting microbial cocktail is then placed into a specially designed cabinet (which looks like a small oven) that controls the temperature and oxygen levels to create favorable conditions for the growth of the microfungi. Over the next few days, the microfungi multiply, which causes the broth to become frothy and cloudy, looking a little like chicken soup. At this stage, the microbial broth is only a few cupsful big. What is truly extraordinary is that this small amount of microfungi can be grown into industrial-scale quantities of microbial meat. The scientists at Quorn then test the microbes in the broth to be sure they are the ones they want (Fusarium venenatum) and not some undesirable imposters that would spoil the entire process. If all is okay, the microbial broth is poured into an enormous fermentation tank made of stainless steel that is almost 40 meters high (Fig. 7.5). Each fermentation tank is housed in a ten-­ story high tower. On my tour, I saw one of the fermentation tanks lying on its side as it was being assembled to create a new production line – it looked like the chassis of the airplane I had flown to England on. After the microfungi are poured into the fermentation tank, oxygen is bubbled through, and the nutrients the microbes need to grow are supplied, including sugars and salts. The temperature, pressure, and pH of the whole processing operation are carefully regulated using a touchscreen computer to foster the growth of the microfungi. It is critical that all the equipment is carefully sterilized before, during, and after production to prevent any undesirable microbes from contaminating the process. Steve told me that a single bad bacteria getting into the process could take over and ruin an entire batch of microbial meat. The small quantity of microfungi initially poured into the fermentation tank use the nutrients supplied to grow and multiply. Over the next 5 weeks, the fluids inside the fermentation tank become more viscous and their appearance changes from fairly clear to highly turbid due to the proliferation of the microfungi. Steve took me inside the production facilities and showed me the different processes occurring inside the fermentation tank. We had to climb eight flights of stairs to reach the top of the tank. Steve flew up the stairs, which I

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attributed to his passion for cycling over the North Yorkshire Moors – climbing those steep hills on a bike will certainly strengthen your legs, lungs, and heart. On the other hand, by the eighth flight, I was severely out of breath and feeling a bit dizzy, which I put down to the fact that I sit on my bottom in front of a computer screen most days. I should also mention that I have severe vertigo. In fact, I am terrified of heights. At the top of the tower, Steve nonchalantly leaned over the wobbly lattice steel platform we were standing on and pointed through a porthole at the bubbling broth inside the fermentation tank, showing me how the microfungi were starting to multiply. All I could see was the gaping chasm and eight flights of nothingness below. Trying not to look too much like a quivering wreck, I did my best to grip the sides of the metal framework and peer into the porthole. Inside looked like a boiling creamy chicken soup – a thick beige fluid with oxygen bubbling through it. Typically, a production run lasts for about 5  weeks. During this time, the microfungi are periodically harvested by siphoning them off from the fermentation tank and then they are turned into meat analogs. But first, it is necessary to remove most of the ribonucleic acids (RNAs). The microfungi Fusarium venenatum contain around ten percent of RNA, a substance naturally found in the cells of all living organisms. When the process used to produce mycoprotein was first developed several decades ago, there were some concerns from health experts that consumption of high levels of RNA could cause gout. Gout is a form of arthritis that is extremely painful, typically affecting the joints of the toes, ankles, and knees. It occurs when there is too much uric acid in the body, which was linked to overconsumption of foods containing high levels of nucleic acids, like those found in RNA and DNA.  For this reason, government regulators required that the RNA be removed from the final product before it was sold. This is normally achieved by heating the microfungi to a temperature that kills them, but still allows the enzymes inside the cells to break down the RNA into nucleic acids and other fragments. These smaller fragments are then removed by centrifuging and filtering the microfungi. Interestingly, RNA is now being sold in health food stores in the form of supplements because it is claimed to have several health benefits. For instance, it is claimed to improve athletic performance, prevent gastrointestinal problems, strengthen the immune system, and reduce aging (but there is little scientific evidence to support these claims). RNA can also be used as a precursor to create food ingredients, such as umami or other savory flavors. The scientists at Quorn are working to convert as many of the sidestreams they generate during mycoprotein production into valuable products so as to improve the economics and sustainability of the manufacturing process.

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Fig. 7.6  Mycoprotein-based products created by Quorn: fillets, southern fried wings, garlic and herb bites, and korma bites (available in the United Kingdom). (Images kindly provided by Quorn (Marlow Foods))

After the RNA has been removed, the resulting microfungi slurry is centrifuged and the mycoprotein is collected as a beige pasty substance that looks, feels, and smells a bit like bread dough. This substance is then chilled and stored. Finally, the mycoprotein is mixed with other ingredients and converted into meat analogs (Fig. 7.6). One of my favorite uses for Quorn is in Greggs’ vegan sausage rolls – I have always missed a good sausage roll since becoming a vegetarian. But other products include cold cuts, mince, nuggets, sausages, patties, and pies. Steve also showed me around the research and development laboratories at Quorn. A team of scientists was working to identify new strains of microfungi that were more efficient or produced more meat-like qualities. The laboratory was full of small fermentation tanks bubbling away, as well as an array of sophisticated forensic devices to characterize the properties of any new strains created. These new strains of microfungi were being produced by taking existing strains and bathing them in ultraviolet light. This causes subtle changes in the DNA of the microfungi, which may lead to desirable new traits. An automated robot was then used to identify any new strains that were able to grow well. These strains were then placed in one of the small fermentation tanks and grown under carefully controlled conditions. After enough microfungi are produced, the scientists at Quorn eagerly test them to see if they have found a new strain that could create more meaty, sustainable, or affordable products.

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As I walked through the Quorn research and development laboratories, I noticed a series of posters on the walls containing microscopy images. These were mug shots of “good” and “bad” microfungi. The good microfungi were stringy filaments that looked like a tangle of wool, whereas the bad ones consisted of stunted filaments that looked more like seaweed. The scientists at Quorn regularly collect samples from the production line and look at them under a microscope to make sure the microfungi have not gone rogue. After it is produced, the microfungi consist of a tangled mess of filaments. To mimic the structural architecture of muscle fibers, which are aligned in particular directions, an additional process is needed. This is done by carefully freezing the microfungi. The ice crystals formed during freezing cause the microfungi to clump together and form aligned fibers somewhat similar to those found in real meat.

Better than Real Meat? If microbial meat is going to compete with real meat, it is important that it has some clear advantages. One of the most obvious benefits of consuming Quorn rather than meat is that it is much more sustainable and environmentally friendly. Beef production requires around ten times more land and water and generates around nine times more greenhouse gas emissions than mycoprotein production. Even chicken, one of the more sustainable sources of meat, requires around twice as much land and water and produces around three times more greenhouse gasses than Quorn. Researchers in Germany recently compared the potential environmental impacts of switching from meat to mycoprotein [11]. Their predictions showed that if everyone replaced 20% of their current meat consumption with mycoprotein by 2050, we would half deforestation and greenhouse gas emissions. At higher substitution levels, the environmental benefits are even more dramatic. Other, life cycle analyses have indicated that substituting beef with mycoprotein would lead to an 80% reduction in greenhouse gas emission, 90% less water use, and 90% less land use. As I saw in Billingham, protein-rich foods can be grown on urban industrial sites, rather than requiring the conversion of our natural environment into agricultural land for animal pasture or to produce animal feed. However, it is still necessary to grow some sugar-rich crops to feed the microfungi, but much less is needed than to feed cows. Because the production facilities used to create mycoproteins can be located next to urban centers, they should also reduce the use of fossil fuels required to transport foods.

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Another potential advantage of mycoprotein is its health benefits [12]. Like meat, it is a good source of high-quality protein, but it also contains high levels of dietary fiber, low levels of saturated fat, and no cholesterol, as well as a range of vitamins and minerals. Nutritional studies have shown that replacing meat with mycoproteins may protect against heart disease, diabetes, and obesity because of its cholesterol lowering, blood sugar lowering, and satiety effects. Because of its good nutritional profile and naturally meat-like texture, meat alternatives made from mycoprotein typically require far less ingredients and processing than those produced from plant proteins, which may be attractive to many consumers looking to reduce their meat consumption but not wanting to eat ultraprocessed foods. Mycoprotein products have been successful on the market for several years. But if they are really going to make a significant contribution to reducing the adverse effects of meat consumption on our environment, it will be necessary to scale their production up substantially. Currently, the global market for mycoprotein is estimated to be around $300 million [13], compared to around $1200 billion for meat [14], meaning that mycoproteins make up less than 0.025% of the total market for meat. Companies like Quorn will therefore have to build many more production facilities like the one I saw in northeast England to improve the sustainability and healthiness of our food supply.

A Diverse World There are billions of different kinds of microbes on our planet, each with its own unique characteristics. Some of these are harmful to us, whereas many others can be used as a source of nutrient-rich foods to feed us. So far, we have seen how Quorn have used microfungi found in soil to create protein-rich foods. But many other food companies have discovered other sources of edible microbes that can replace meat. Nature’s Fynd is a company based in Chicago that grows filamentous fungi to create meat alternatives. In this case, the microfungi were found in a geothermal spring in Yellowstone National Park. Nature’s Fynd was co-founded by Dr. Mark Kozubal who discovered this species of microfungi when doing his graduate research on extremophiles, which are microbes that can survive in extremely harsh conditions. He identified a filamentous microfungus called Fusarium strain flavolapis in the geothermal springs, which he found could be grown in fermentation tanks like the microfungi used to produce Quorn. Because this microfungus naturally has a filamentous structure, it can mimic many of the desirable textural attributes of real meat. According to the company’s CEO, Thomas Jonas, one of

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the biggest advantages of this “nutritional fungi protein” is that it can be produced “24 hours a day, seven days a week, and 365 days a year” in almost any location, which makes it much more versatile than the proteins obtained from meat or plants [15]. Despite their name, mycoproteins are not only protein, they contain a mixture of nutrients, including proteins (45%), dietary fibers (25–35%), and fats (5–10%), as well as vitamins and minerals. Their nutritional quality is therefore much better than many plants and similar or better than meat. Nature’s Fynd are now selling a range of products based on their mycoprotein, which they call Fy™, including breakfast patties and cream cheese. A sustainability analysis carried out by the company reported that they require 99% less land and 87% less water to produce than the same amount of beef. Like several other sustainable protein companies, the technology they have developed is being explored for its potential to create foods for astronauts. This research is supported by NASA, who want to grow foods for long-­ haul space missions and for colonists living on our moon or on other planets. Several other companies have identified other kinds of microbes that can be used as a source of food to replace meat. Just like we have meat from cows, pigs, sheep, and chickens now, we may have meat from many different species of microfungi, bacteria, and yeasts in the future, each with its own unique look, feel, and taste. Moreover, these microbes can be selectively bred to improve their nutritional and meat-like properties, just as livestock animals have been over the past century or so. Selective breeding has created animals that grow much quicker and produce much more meat than their ancestors. The same approach can be used to create microbes that grow more efficiently or have different sensory and nutritional profiles, thereby reducing costs and environmental impacts, while also improving the quality and nutrition of the final products.

Food from Air The mycoproteins produced by Quorn and Nature’s Fynd require a source of nutrients to feed the microfungi, which are usually sugar-rich agricultural crops or their residues. Indeed, one of the big environmental benefits of this kind of microbial meat is that it can be used to convert waste materials from the agricultural industry into valuable protein-rich foods for humans. Recently, however, there has been interest in using an even more environmentally friendly source of nutrients for feeding microbes and converting them into foods – air! Solar Foods is a Finnish company that has developed an innovative way of getting microbes (autotrophic bacteria) to produce protein-rich meat analogs

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using only air, sunlight, and a few minerals. Creating foods from sunlight and air may appear extremely far-fetched but this is what green plants do all the time through photosynthesis. These plants use the energy in sunlight to convert the oxygen and water in air into carbohydrates and carbon dioxide. The scientists at Solar Foods claim the industrial process they have developed is 20 times more efficient at producing foods than the natural photosynthetic process used by plants. Like the microfungi used to produce mycoproteins, and the mammalian cells used to produce cultured meat, the bacteria used to produce foods by Solar Foods are grown in large fermentation tanks. The carbon dioxide and water in air are used as a source of nutrients, whereas electricity generated by solar panels is used as a source of energy. This energy is used to split the water in the air into hydrogen and oxygen gasses, which are then fed into the fermentation tank along with carbon dioxide from the air. A few salts, such as calcium, potassium, and phosphorus, as well as a nitrogen source (ammonia), are also added because they cannot be obtained from air. Initially, only a few bacteria are present in the fermentation tank but after a few weeks they multiply until billions are present. These bacteria are then collected, purified, and dried. The final product is a mustard-colored nutrient-dense powder known as Solein® that can be used as a food ingredient to formulate meat analogs and other foods. One of the advantages of this ingredient is that it does not have a strong taste or smell so it can be incorporated into a wide range of food products without affecting their desirable flavor. Solein® also had good nutritional attributes as it contains proteins, dietary fibers, healthy fats, vitamins, and minerals. The company reports that it contains around 65–70% protein, 5–8% fats, 10–15% dietary fibers, and 3–5% minerals. It therefore has a better nutritional profile than many meat and plant products. Images of the bioreactors used, the protein-rich powder produced, and the food products that can be created from this ingredient are shown in Fig. 7.7. Solar Foods claims its fermentation process is a much more sustainable way to create edible proteins than raising livestock or even agricultural crops (Table 7.1). It requires 600 times less water and 200 times less land to produce a kilogram of Solein® protein than to produce the same quantity of beef protein. Moreover, Solein® production generates 200 times less greenhouse gas emissions. In addition, the process used does not cause pollution because it is a closed-loop system, thereby avoiding the eutrophication associated with livestock production. These kinds of microbial farms can be built in a diverse range of locations around the globe, including those usually unsuitable for growing foods, like arid deserts. They therefore offer an innovative means of reducing the negative environmental effects of modern livestock production, as well as responding to changes in climate caused by global warming. If Solar Foods technology becomes successful, the agricultural land normally used to

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Fig. 7.7  Solar Foods are creating protein-rich ingredients from air and sunlight by growing specific kinds of microbes in bioreactors (Images kindly supplied by Solar Foods) Table 7.1  Comparison of the environmental impacts of producing different kinds of proteins (per kg of protein) Environmental impact

Beef

Plants

Solein

Water use (1000s of liters) Land use (m2) GHG emissions (kg CO2-eq/kg protein)

600 200 200

100 20 5

1 1 1

Reported by Solar Foods (solarfoods.com)

raise cattle could be rewilded with grasses or trees, which would pull carbon dioxide from the air, thereby helping to reduce global warming. As with other innovative technologies, one of the challenges that Solar Foods must overcome is to create a process that can economically produce the vast quantities of protein needed to make a dent in the traditional meat industry. When I was attending a conference in Denmark, I had a few beers with Petri Tervasmäki from Solar Foods, a biotechnologist responsible for setting up and running the Solein® production process. Previously, he had worked in a microbrewery producing craft beers, but he was now employing his brewing skills to grow edible bacteria. Indeed, the fermentation process used to create this innovative protein-rich food is very similar to the one used to produce beer. I was really impressed by the non-alcoholic beers available in Denmark and recommended one of them to Petri. After carefully tasting it and assessing

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its sensory attributes, he gave me his considered verdict: “cat piss.” As soon as he said it, my perception of the beer in my hand changed and I could not drink it again. I am sure Petri is now using his discerning skills to optimize the sensory attributes of Solein®. Another potential application of this technology is to produce foods for future generations living on other planets. In 2018, Solar Foods started a collaboration with the European Space Agency to produce foods for long-haul space missions and Martian colonies. The conditions on the red planet are very different from those on Earth, but it still has sunlight and carbon dioxide in its atmosphere, which means that it may be possible to produce foods using the innovative approach developed by Solar Foods. Solar Foods is not the only food company that is claiming that it can help solve the global food crisis by generating food from air. Air Protein is a Californian company co-founded by Dr. Lisa Dyson and John Reed, who got their PhDs in Physics and Materials Science and Engineering from the Massachusetts Institute of Technology (MIT), respectively. These hard-core science backgrounds are typical of the founders of many of the innovative start-up companies in the alternative protein space – they are established by people who have not been trained as traditional food scientists but want to use their scientific and entrepreneurial skills to solve the major global food challenges affecting us all. Drs. Dyson and Reed were inspired by research originally carried out by NASA scientists during the space program in the 1970s, who first proposed the concept of creating proteins from air but never developed it on a commercial scale. Drs. Dyson and Reed are now trying to turn this concept into a commercial reality. The process they use is very similar to the one developed by Solar Foods. They use air, water, and a renewable energy source, plus a few minerals, to feed microbes in a fermentation tank. They then harvest and purify the microbes so they can be used as a versatile and nutrient-rich ingredient for creating meat analogs. One of the big advantages of this process is that proteins can be produced much more quickly and sustainably than real meat. The company claims they can produce protein-­ rich foods within 4 days on their “Air Farms,” compared to 3 months for soy, 5  months for chicken, and 2  years for beef. Moreover, no antibiotics, hormones, pesticides, or herbicides are needed to grow the edible microbes, thus overcoming some of the problems linked to the production of animal or plant proteins. Working with culinary scientists they have shown they can create air chicken, fish, and scallop from their edible microbes (Fig. 7.8). If the technologies developed by Solar Foods and Air Protein can be successfully scaled up, they could revolutionize the way we produce foods, reducing deforestation, greenhouse emissions, pollution, and animal welfare concerns.

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Fig. 7.8  Chicken and scallop analogs produced by Air Protein from air and sunlight by growing microbes in bioreactors. (Images kindly supplied by Air Foods)

Food could be grown almost anywhere using much less land and water and without generating greenhouse gasses. Air Protein claims they can produce as much food in an area the size of Disneyland as can be produced using conventional farming on an area as big as Texas. But, again, it is going to take some time before they have developed sufficient production capacity to impact meat consumption globally.

Precision Fermentation: Milking Microbes Precision fermentation is another biotechnological innovation being used to create more sustainable alternatives to meat and other animal products. In this case, though, we do not eat the cells themselves, as we do with cultured or microbial meat. Instead, we use the cells to produce ingredients that we can then assemble into meat, seafood, milk, or egg analogs. This is somewhat like farmers using cows to produce milk, which is then used as an ingredient to make other foods, like yogurt, cheese, or cream. The production of foods using fermentation is not a modern invention. Fermentation has been used for over a thousand years to produce bread, cheese, beer, and wine, although our distant ancestors would not have been aware that tiny microbes were involved in this process. Traditional fermentation has also been used to create products like tofu and tempeh, which have been used as alternatives to meat in Asia for hundreds of years and are finding

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increasing popularity globally, but we will cover these meat alternatives in a later chapter. I live in Western Massachusetts, where I am surrounded by microbreweries. The large fermentation tanks the brewers use to convert grains into beer are often visible. These tanks contain a slurry of yeast cells that convert the sugars in grains into alcohol. To consistently produce good beers, like the deliciously hazy New England IPAs that are a specialty of my region, it is important to carefully control the microbes, grains, and brewing conditions used. Similarly, ingredients that can be used to create meat alternatives can be produced in fermentation tanks by carefully controlling the microbes, feed sources, and operating conditions employed.

What Is Precision Fermentation? In conventional fermentation, like beer and wine production, brewers typically use a commercial source of yeast to ferment their grains. They do not need to have a deep understanding of the complex biochemical processes occurring inside microbial cells because yeast has been used for centuries to produce alcohol and appropriate strains and growing conditions have already been established through years of experience. In contrast, for precision fermentation, a much deeper understanding of cell biology is required because the microbial cells are being used to create a diverse range of new molecules, such as flavors, colors, fats, proteins, enzymes, vitamins, and growth factors. Biotechnologists need to know how to program the microbes to precisely produce the molecules they desire. These molecules can then be used as ingredients to improve the look, feel, taste, or healthiness of meat alternatives. For instance, the colors and flavors can be used with plant ingredients to create better quality plant-based foods. Impossible Foods uses leghemoglobin produced by precision fermentation in its plant-based meat products to provide the desirable colors and flavors normally provided by myoglobin in real meat. Precision fermentation can also be used to produce the growth factors needed to promote the proliferation of meat cells in cultured meat products without the need for any animal inputs (like fetal bovine serum). Precision fermentation is therefore a versatile enabling technology with a wide range of applications in the alternative protein industry.

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I Love GMO Ginkgo Bioworks is a pioneering biotechnology company based in Boston, Massachusetts, that specializes in precision fermentation. It uses biotechnology to program cells to produce specific kinds of molecules that are useful in the food and other industries. For instance, it can create flavors by identifying gene sequences in nature that are responsible for producing them, then synthesizing these sequences, and inserting them into yeast cells. The yeast cells produce these flavors as they grow, which can be collected, purified, and used as ingredients in foods, perfumes, and other products. Ginkgo was founded by Professor Tom Knight and several of his graduate students from the nearby Massachusetts Institute of Technology. I went on a guided tour of the Ginkgo facilities a few years ago. Our guide was an energetic young woman called Kit who was passionate about genetic engineering and its potential to create a better world. After entering the Ginkgo facility, we came across a group of scientists working on computers in a space that looked like a trendy coffee shop. They were designing and testing DNA molecules on their computers using advanced software programs that simulate the complex biochemical processes occurring inside microbial cells. The scientists were using the software to discover how specific changes made to DNA affect the kinds of molecules the microbial cells can produce. They could then use this information to design DNA sequences that could be inserted into microbes to produce desirable food ingredients, like colors, flavors, fats, proteins, or vitamins, as well as drugs and vaccines. They were also using the software programs to optimize the performance of microbes already used to create traditional foods, like beer, bread, and cheese, so they would work more efficiently, thereby lowering costs and improving sustainability. On our tour, we then moved into a research and development laboratory that was equipped with advanced biotechnology and analytical instrumentation (Fig. 7.9). Many of these instruments were fully automated, with little need for human intervention. Robots prepared and tested hundreds of samples at a time, which allowed the company to quickly screen microbes with different genetic traits to establish which ones were most suitable for producing the new ingredients or functions they required. After the scientists working with the computer software identify a DNA sequence that will program the yeast or bacterial cells to produce the desired target molecule, they send this information to one of the machines in the research and development lab. This machine then builds the required DNA

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Fig. 7.9  Precision fermentation uses the modern tools of biotechnology to create specialized ingredients for use in the food and other industries. (Images kindly provided by Ginkgo Bioworks)

sequence from nucleotide building blocks. After this DNA sequence has been produced it is introduced into a microbial cell. The microbes are then incubated in a broth of nutrients under carefully controlled fermentation conditions, which allows them to grow and replicate. As part of their natural life cycle, the DNA sequence is read within the microbial cells, and new proteins are produced that are either used as ingredients themselves or to regulate the biochemical pathways inside the cells so they produce the desired target molecule (such as a flavor, color, or vitamin). The efficiency of the microbes at producing these molecules is then established by measuring the quantity and purity of the target molecules. Multitudes of different microbes with slightly different genetic modifications are tested to identify the most efficient ones for the required task. The scientists will also examine the effects of the nutrient blend, temperatures, and oxygen levels used during fermentation on the performance of the microbes to find the optimum production conditions. This process is like that used by the brewing industry to establish the optimal conditions for fermenting beer from yeast. Incidentally, Boston’s famous Harpoon Brewery is located only a short distance from the Ginkgo Bioworks facility, which is likely to use similar kinds of optimization processes to create new beers or to guarantee the quality of their existing ones. Ginkgo Bioworks uses genetic engineering to create many of its food ingredients. Some consumers are wary of consuming foods produced using genetic

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engineering, especially in Europe. In the United States, people have been consuming genetically engineered foods for decades, such as corn, soy, and wheat, with few confirmed adverse effects. On our tour, the guide explained that Ginkgo Bioworks did not want to make the same mistakes that some of the early pioneers of genetic engineering made, like Monsanto. They intended to be fully transparent about both the benefits and potential risks of this technology. It should be noted that the ingredients produced by precision fermentation typically have the same or very similar properties as those found in nature. It is the microbes used to produce them that are genetically engineered. The ingredients produced by these microbes are separated from them after they have been produced, and so the microbes themselves are not consumed. At the end of the Ginkgo Bioworks tour our guide gave us all an “I Love GMO” sticker. I thought this was a bold move. If we are going to address some of the major issues facing the global food supply, then it is important that we can use every tool available. Provided genetic engineering tools are safe, I believe it is critical they can be used to improve the resilience and productivity of our modern food system. Their widespread acceptance will require biotechnology companies to demonstrate their safety and to be transparent about their origin and use.

Fermenting Our Future Foods The precision fermentation industry combines the ancient wisdom of traditional food fermentation with the advanced knowledge of the biotechnology industry, like that gained from the production of biofuels and biopharmaceuticals [16]. This industry has grown rapidly over the past few years with the increasing interest in alternative proteins, with hundreds of start-up companies or established companies now focusing on fermentation. Many of these companies are using fermentation to produce new kinds of molecules that can be used to formulate alternatives to animal products. This requires optimization of the microbial strains, feedstocks, and fermentation conditions used to produce these target molecules, as well as the processes used to incorporate them into desirable food products.

Special Effects – Colors and Flavors The color and flavor of real meat products are strongly influenced by the presence of hemoglobulin and myoglobin, which are proteins responsible for

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carrying oxygen around the blood and storing it in the muscles, respectively. Both these proteins contain a specialized molecular feature, known as heme, that contains iron and is able to bind oxygen. The scientists at Impossible Foods, one of the most successful plant-based food companies in the United States, realized the importance of these heme proteins in governing the desirable quality attributes of meat products. They therefore searched nature to see if they could identify a plant-based source of heme protein that would provide similar qualities. They found one in the roots of soybeans but there was not sufficient present to be used in the vast quantities of plant-based burgers and other meat analogs that the company needed to produce to compete with the traditional meat industry. For this reason, they turned to precision fermentation. They identified the gene responsible for producing leghemoglobin in soybeans and then engineered it into a microbe. They then used precision fermentation to produce the leghemoglobin in large quantities. When incorporated into food products, this plant-based heme protein behaves very similarly to the myoglobin and hemoglobin in real meat, producing similar colors and flavors during cooking. This is one of the reasons why Impossible Foods’ products turn from red to brown when they are cooked. During heating, the leghemoglobin proteins unravel, which releases the iron and promotes a series of chemical reactions that generates meat-like flavors and colors. My research team has worked with another company that produces heme proteins using precision fermentation. Motif FoodWorks, a spin-off of Ginkgo Bioworks, uses yeast cells to produce an ingredient known as HEMAMI™ that is almost identical to bovine myoglobin. They also have the technology to produce myoglobin ingredients from a wide range of other animals, including chickens, horses, whales, and tigers. In nature, each of these animals lives in a different environment and has different oxygen requirements, which means they contain slightly different versions of myoglobin because of different evolutionary pressures. As a result, these ingredients perform differently in foods, e.g., they may be more or less stable during food storage or cooking, which may be advantageous for some applications.

Leather and Desserts – Gelatin Replacements The connective tissue in meat and seafood contains high levels of protein known as collagen. This protein is a long stiff rod-like molecule that provides mechanical strength to animal tissues and contributes to the desirable texture and mouthfeel of meat. Collagen is also found in the bones, hooves, and cartilage of livestock animals and fish. These byproducts are often collected and

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then boiled in strong acids or alkalis to create gelatin, which is widely used as a gelling agent in the food and other industries. For example, the clear wobbly fruity jellies marketed as Jell-O™ are made from this ingredient. These jellies can be formed by adding powdered gelatin to hot water, which causes the gelatin molecules to unravel – in technical terms they undergo a helix-to-coil transition. When this hot solution is cooled, the gelatin molecules form helical regions again that crosslink with each other through hydrogen bonding, thereby leading to the formation of a transparent gel. It has proved very challenging to find ingredients from plants that accurately simulate the desirable properties of collagen and gelatin. For this reason, several companies have used precision fermentation to create animal-free versions of these proteins that can be used in the food and other industries. Geltor is a Californian company that uses precision fermentation to produce collagen. Its co-founders, Drs. Alex Lorestani and Nick Ouzounov, met during their graduate studies at Princeton University. Like many other young people who have started companies in this area, they were passionate about addressing global food challenges using modern science. Geltor creates collagen ingredients that can be used to formulate better meat alternatives, as well as personal care and cosmetic products. There are huge financial opportunities in this area: the traditional collagen market is worth over $8 billion, with most of these ingredients being used in the food industry [16]. This is one of the reasons start-up companies in this area are receiving bucketloads of cash from investors. Indeed, there was more than $1.7 billion of investment in fermentation technologies in 2021, which is an extraordinary increase of nearly 30-fold in just 4 years [16].

Guilty Pleasures – Fats and Oils As well as producing proteins, microbes can also be harnessed to produce other ingredients that can be used to formulate meat-free meats. Several companies use precision fermentation to create fats and oils. Microbes that naturally produce high levels of fats, or can be genetically reprogrammed to do so, are used for this purpose. These microbes can be instructed to produce fats with similar quality attributes as those found in real meat, like the ability to solidify at room temperature and melt when heated. The meltability of fats plays a critical role in the desirable texture and mouthfeel of real meat, and so it is important to simulate this characteristic in meat analogs. Alternatively, microbes can be reprogramed to produce healthier fats than those found in animals, for example, by reducing the saturated fat level or increasing the

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polyunsaturated fat level. Another advantage of fats and oils produced by precision fermentation is that they can be used instead of plant-based ones that have been linked to environmental or societal concerns, like palm oil.

Animal-Free Milk and Eggs As well as creating ingredients for use in meat and seafood analogs, many precision fermentation companies are producing them for use in egg and dairy analogs. Several of these products have already been successfully launched onto the market. Perfect Day, another California-based company, uses precision fermentation to produce a protein found in milk, which has been used to create animal-free milk, cheese, and ice cream. A sustainability analysis showed that producing this milk protein using microbes was much more environmentally friendly than producing it using cows, with 97% less greenhouse gas emissions, 96% less water use, and 27% less energy use [16]. EVERY, yet another Californian company, is doing a similar thing with egg proteins. Despite the current prevalence of precision fermentation companies in the United States, they are also being established in many other places around the world. One of the main bottlenecks in precision fermentation is the lack of manufacturing facilities to produce the large quantities of ingredients required by the food industry [16]. Many of the existing facilities are remnants of the pharmaceutical and biofuel industries, which are becoming old and were not designed with the needs of food production in mind. There is therefore a pressing need for more government and industry investment to build the additional manufacturing facilities needed to make this industry commercially viable. Given the extensive environmental damage associated with the meat industry, this should be an important priority for public funding in the near future.

My Takeaway It is clear that biotechnology will play a critical role in the development of a healthier and more sustainable food supply. The ability to economically cultivate animal, insect, and microbial cells in large fermentation tanks is providing us with a way to grow foods that causes much less damage to the environment and does not involve the industrial-scale confinement and slaughter of animals, with all the cruelty and pain that involves. Tasty, healthy,

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and affordable meat-like foods can now be produced in factories located close to urban centers, thereby reducing transport costs and environmental impacts. Moreover, much of the land currently used to raise and feed livestock could be freed up, which would lead to appreciable reductions in greenhouse gas emissions, pollution, and water use, as well as increases in biodiversity when this land is repopulated by wild plants and animals. However, this industry is still in its early stages and more funding is urgently needed from governments and investors to ensure it can reach a size where it will have an impact on the global food supply.

References 1. Sprecht, L., Is the Future of Meat Animal-Free. Food Technology, 2018. 1: p. 17-21. 2. Cassiday, L., Clean Meat. INFORM, 2018. 29(2): p. 6-12. 3. Bercovici, J., Why This Cardiologist Is Betting That His Lab-Grown Meat Startup Can Solve the Global Food Crisis, in Inc. 2017. 4. Alexander, P., et al., Could consumption of insects, cultured meat or imitation meat reduce global agricultural land use? Global Food Security-Agriculture Policy Economics and Environment, 2017. 15: p. 22-32. 5. Flachowsky, G., U. Meyer, and K.H. Sudekum, Invited review: Resource inputs and land, water and carbon footprints from the production of edible protein of animal origin. Archives Animal Breeding, 2018. 61(1): p. 17-36. 6. Smetana, S., et al., Meat alternatives: life cycle assessment of most known meat substitutes. International Journal of Life Cycle Assessment, 2015. 20(9): p. 1254-1267. 7. Reynolds, M., The clean meat industry is racing to ditch its reliance on foetal blood, in Wired UK. 2018, Wired. 8. Fassler, J. Lab-grown meat is supposed to be inevitable. The science tells a different story. The Counter, 2020. 9. Humbird, D., Scale-Up Economics for Cultured Meat Techno-Economic Analysis and Due Diligence. 2020, Open Philanthropy: San Francisco, California USA. p. 1–104. 10. Humbird, D., Scale-up economics for cultured meat. Biotechnology and Bioengineering, 2021. 118(8): p. 3239–3250. 11. Humpenöder, F., et  al., Projected environmental benefits of replacing beef with microbial protein. Nature, 2022. 605(7908): p. 90–96. 12. Coelho, M.O.C., et al., Mycoprotein as a possible alternative source of dietary protein to support muscle and metabolic health. Nutrition Reviews, 2020. 78(6): p. 486–497. 13. FMI, Mycoprotein Market. 2022, Future Market Insights. 14. Statistica, Meat – Worldwide. 2022, Statistica.

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15. Watson, E. Nature’s Fynd to launch at Whole Foods, expects large-scale nutritional fungi protein plant to be operational in 2023. 2022; Available from: https://www. foodnavigator-­usa.com/Article/2022/03/16/Nature-­s-­Fynd-­to-­launch-­at-­WholeFoods-­expects-­new-­nutritional-­fungi-­protein-­plant-­to-­be-­operational-­in-­2023. 16. Bushnell, C., Fermentation: Meat, seafood, eggs and dairy. 2022, The Good Food Institute: Washington, DC. p. 1–79.

8 Bug Meat: Assembling Meat from Insects

Abstract  Insects are highly nutritious alternatives to meat, containing good levels of proteins, fats, dietary fibers, vitamins, and minerals. They are already widely consumed around the globe, but many people in the West are reluctant to eat them because of neophobia and disgust. Innovative chefs and food companies are trying to overcome this problem by creating next-generation insect-based meat alternatives. Recent research on the taste-testing of bug burgers is discussed, as well as the development of insect farms capable of creating foods for humans. Insects can be consumed whole, or they can be converted into functional ingredients that can then be used to create food products, like meat analogs. Consumers often prefer to eat insects when they are disguised in foods. The utilization of insects as a source of health-­promoting food ingredients (nutraceuticals) that are claimed to have health benefits is also highlighted. Finally, the environmental, ethical, health, and safety implications of switching from meat to insect-based meat analogs are discussed. Keywords  Insects • Crickets • Meal worms • Insect burgers • Health • Sustainability • Ethics We should be eating bugs to save the world. Phil Torres

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 D. J. McClements, Meat Less: The Next Food Revolution, Copernicus Books, https://doi.org/10.1007/978-3-031-23961-8_8

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What’s for Dinner? Bug Meat! As I started writing this chapter, I had to battle a huge bug flying menacingly around our living room. It was making a horrible vibrating sound as it flew erratically around my head, before eventually crawling under a bookcase. After some trepidatious poking and prodding with a piece of card, the bug scuttled out of the dark and headed straight for me. I batted it down, sprayed it with bug spray, and threw it in the garden. I never thought about picking it up and eating it. Using an online app, I identified it as a roundneck sexton beetle (Nicrophorus orbicollis), which is apparently some kind of necrotic burying beetle that feeds off the carcasses of dead animals – nice! Like many people who have grown up in the West, I do not usually think of insects as something to put on the menu. Instead, I think of them as pests that I want to keep out of my food and out of my face. I was therefore surprised to find out there is a growing movement in several Western countries in turning bugs into a nutritious, sustainable, and environmentally friendly alternative to animal meat [1, 2]. In this chapter, I will try to convince you of the merits of eating bugs, assuming you are not already an insect gourmand.

Eating Bugs Is Normal Many species of insects are suitable for human consumption. Indeed, more than 2000 different kinds of bug are already eaten by people around the world [1]. These bugs include ants, beetles, bees, caterpillars, cicadas, cockroaches, crickets, dragonflies, flies, grasshoppers, grubs, locusts, stink bugs, termites, and wasps [3]. Scientifically, the consumption of bugs is referred to as “entomophagy,” which is a relatively new word in the English language. This may be because cultures that traditionally consumed bugs had no need to coin a separate word to describe eating them rather than any other kind of food. In the West, we don’t have a specific word for eating prawns. Insects are nutrient-dense critters that can be raised more efficiently and sustainably than livestock animals. They contain high-quality proteins, fats, dietary fibers, vitamins, and minerals, which means they are a nutritious alternative to meat. They are more efficient at converting feed into protein-rich foods than livestock animals (Fig. 8.1). They can also convert low value sidestreams from the agriculture industry into foods for humans or animals. Moreover, raising bugs for foods requires less water and land than livestock animals and generates less pollution and greenhouse gas emissions. There are

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Protein Yield (g /m2/yr)

30 25 20 15 10 5 0

Beef

Pork Poultry Fish Protein Source

Insect

Fig. 8.1  Amount of protein yield that can be produced in a given area from different sources of proteins. Insects are particularly effective at converting their feed into proteins that humans can eat. (Figure replotted from data obtained from Alexander et al. [1]. Locust photo by Bernard Goldbach via Flickr.com [CC BY 2.0])

several reasons that insects are highly efficient at converting their feed into bug meat. It is often possible to consume all of an insect, whereas less than half of an animal is typically eaten. Bugs do not need to maintain their bodies at a constant temperature, like animals do, and so they need less energy to grow and survive. Insects can even adapt their behavior to the surrounding temperature and so can “hibernate” in colder times. They also tend to reproduce and develop much more rapidly than large animals like cows, pigs, and sheep. There are therefore many good reasons for consuming bugs as a sustainable source of proteins. Bugs have been an important part of the human diet for much of human history [4]. They are still consumed on a regular basis in many parts of the world, with over two billion people eating them [5]. They are commonly consumed in Africa, Asia, Central America, and South America for their desirable taste and nutritional value. These bugs may be collected from nature, raised on small farms, or produced in large industrial facilities [2]. Each species of edible insect has its own unique look, feel, and taste, just like chicken, pork, beef, and lamb do. The witchetty grub is the chubby white larvae of an Australian moth that is a delicacy to many Aboriginal people. According to Food & Wine magazine these grubs have an almond taste when eaten raw, but a chicken taste when roasted, including a crispy skin like that found on roast

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chicken. The magazine recommends the best way to eat witchetty grubs is to “Grab the insect by the head and chomp.” Crickets have been reported to have a nutty umami flavor. However, there is a tendency for their legs and wings to get stuck in your teeth, and so it is recommended these are removed prior to putting them in your mouth. I can attest to this. As part of a graduate class that I teach on Future Foods, I tried some edible crickets (as I had asked my students to taste them, it only seemed fair that I do the same). I spent the next few hours picking them out of my teeth – not a pleasant experience. As Chef Joseph Yoon, the co-founder of Brooklyn Bugs, pointed out in an interview with The Guardian, we need to learn how to prepare and cook all the different species of bugs available to bring out the best in them. When cooked properly, roast crickets are nutty, black ants have a citrusy tang, bamboo worms are creamy, and palm weevils are coconutty. In the supermarkets and restaurants of the future, we may be faced with a diversity of exotic dishes with unique textures and tastes, each made from a different species of bug cooked in a different way: soft and juicy, crispy and crunchy, or creamy melt-in-your-mouth.

Cooking with Bugs The consumption of bugs is not common in the United States and Europe where meat consumption is most prevalent. Most people in these countries currently find the thought of eating bugs to be repulsive [6]. There are, however, a growing number of more adventurous and environmentally conscious individuals who are turning to insects as a food source because of their sustainability credentials. Several kinds of insect species are being explored as potential replacements for meat, including ants, crickets, grasshoppers, mealworms, and wax worms. The mealworm, a larva of the flour beetle, is one of the most popular edible bugs because it is relatively easy to breed, raise, and turn into foods (Fig. 8.2). The growing interest in eating bugs is seen in the recent popularity of insect-themed recipe books. The Eat-a-Bug Cookbook by David Gordon contains recipes for “Curried Termite Stew,” “Grubsteaks,” and “Deep-fried Tarantula Spider.” Adventurous diners can eat bugs whole with their legs, wings, antennae, and eyes intact (crickets) or with their little heads attached to their chubby bodies (grubs). The most squeamish among us may prefer to eat insect flours that are integrated into our foods in a form where we are not aware of the original insect.

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Fig. 8.2  Yellow mealworm larvae: whole (left) and powdered (right). (Photo by Xue Zhao, SLU, Sweden. Image from Elhassan et al. [7]. Creative Commons CC BY license)

Fig. 8.3  Christian Bartsch (left) is the founder of Essento, which makes bug-based burgers and meat balls that are sold in supermarkets in Switzerland and other European countries. (Photographs kindly provided by Essento)

In Europe, several food companies and restaurants are already selling edible insects as alternatives to meat. The Swiss company Essento, whose tag line is “Making Insects Delicious,” has created bug burgers by mixing mealworms with vegetables, herbs, and spices. These products are now being sold in supermarkets in several European countries (Fig. 8.3). I had the pleasure of talking to Christian Bartsch, the CEO and founder of this company, as he sped across Europe on a high-speed train after attending a future foods conference in Brussels. Christian trained as an economist but has always had a passion for changing the world through food. One of his primary motivations

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for starting the company was to combat the devasting effects of climate change by developing a sustainable high-quality source of protein that could reduce our reliance on meat. He believes that bug meat has an important role to play in meeting our future protein needs. Flying Spark is an Israeli company using fruit fly larvae to create protein-­ rich ingredients for use in human foods, pet foods, and cosmetics. They have used their insect protein to create a canned-tuna substitute by combining it with colors, flavors, and spices to match the look, feel, and taste of real tuna. Hargol is another Israeli company that is creating burgers and falafel balls from locusts, which they raise in solar-powered farms. Ÿnsect is a French company based in Paris that produces protein-rich ingredients that are used to create foods for humans, pets, and livestock animals. These ingredients are produced from dried buffalo mealworms raised in vertical farms using waste products as feed. Grub Kitchen is a café and restaurant in the United Kingdom that uses insects in several of its dishes, including a bug burger, a Bolognaise with insect mince, and spiced cumin and mealworm hummus. The bug burger is a “blend of toasted crickets, mealworms, and grasshoppers, spinach, sundried tomato and seasonings.” Eat Grub is an online retailer in the United Kingdom that sells a variety of insects for human consumption, including crickets, grasshoppers, and mealworms (eatgrub.co.uk). They have a number of delicious recipes for the bug-curious (along with appetizing photographs), including “mealworm, parmesan, and chive omelet,” “cricket and bean taco,” and “grasshopper porridge.” In 2018, Sainsbury’s, one of the largest supermarket chains in the United Kingdom, began to sell edible insects as a snack food [8]. Their smoky barbecue-­flavored crickets were marketed as a healthier and more sustainable alternative to potato chips. When I was writing a previous book, Future Foods: How Modern Science Is Transforming the Way We Eat, I asked my nephew Jake, who had just finished his PhD in Material Science at the University of Edinburgh in Scotland, to carry out a “crunchy cricket” taste test on these snacks. He purchased a packet and invited a bunch of his friends round to sample them. One of his friends said, “looks like a dead bug you would find on the floor or under a rock in your back garden,” while another thought they looked “off putting” and “not very appetizing.” Overall, Jake and his friends thought the mouthfeel of the crickets was “a bit dry,” “dusty,” and “airy,” while their flavor was “nutty,” “woody,” and “earthy.” He and his friends thought the bug snacks didn’t taste bad, but they didn’t taste great either. Going above and beyond the call of duty, Jake also tried them as a crunchy topping on a slice of pizza, which improved their palatability somewhat  – or so he told me (Fig.  8.4). An interesting observation that Jake made was that his younger

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Fig. 8.4  My courageous nephew, Dr. Jake McClements, trying a cricket-topping on his pizza. Crickets have been introduced into some British supermarkets as a snack food

friends (mainly in their 20s) were happy to try bugs, whereas their parents (mainly in their 50s) were “utterly disgusted” and not even willing to put them in their mouth. When developing bug-based products it may therefore be useful for manufacturers to target the younger generation. If they can accept them when they are young, they may continue to eat them later in life. One way to get around the resistance some people have to eating whole insects, with all their legs, wings, and faces on full display, is to disguise them inside other foods. Insect flours are prepared by drying and grinding up bugs. These protein-rich flours can then be used to create bug-based products, like insect burgers, sausages, or meatballs. In this case, you don’t have to come face to face with the bug you’re eating. This approach is similar to the one we take when eating real meat. It is easy to forget you are eating a cow, a pig, or a chicken when you are chomping on a real burger, sausage, or meatball. The creation of delicious bug-based foods requires scientists to understand how the proteins, fats, and fibers in insect flours contribute to their desirable look, feel, and taste. Over the past few years, there has been a dramatic increase in scientific research on the incorporation of insects into foods. As our knowledge increases, it may become possible to create bug-based meat that is indistinguishable from real meat.

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The Science of Bug Meat Cows, pigs, sheep, and chickens can be cut into chunks like beef steak, pork loin, lamb chops, or chicken breast, or they can be minced into small pieces that do not resemble the original tissues in the animal, like ground beef. These meat products can then be cooked and eaten. As mentioned earlier, insects can be eaten whole, or they can be ground into powders. Unlike minced meat, these powders cannot simply be cooked and consumed. Instead, they must be mixed with other food ingredients to form bug-loaded meat analogs. For instance, a bug burger may be created by mixing powdered mealworm with water, cereals, flavors, colors, and spices, then molding the insect-dough into a patty and cooking it. There have been decades of scientific research on the changes occurring within animal tissues when they are converted into meat and cooked. Scientists now have a detailed understanding of the complex physical and chemical changes that happen inside real meat when it is cooked, which the meat industry uses to perfect its products. The proteins in the tissues play a critical role in determining the desirable texture and mouthfeel of beef, pork, lamb, and chicken. When meat is heated, the proteins in the muscles and connective tissue unravel and then coagulate with each other, leading to the formation of a 3D network that traps fluids and provides mechanical strength, thereby contributing to the juiciness and chewiness of meat products. Because of their potential as a healthy and sustainable alternative to meat, more and more scientists are directing their attention to understanding the changes that occur inside insect meat when it is used to create foods. However, this is still a relatively new area of food science and there is still a long way to go before we can fully understand the culinary complexities of insects. For instance, what is the best temperature and time to cook a mealworm burger to get a desirable appearance, texture, mouthfeel, and flavor? What molecular events contribute to the look, feel, and taste of these products? How do other ingredients in foods influence the behavior of the bug ingredients? The lack of knowledge in this area was nicely highlighted by a team of Korean scientists trying to enrich meat batters with silkworms: “meat products added with silkworm pupae powder have been insufficiently examined” [9]. This team partly addressed this knowledge gap by showing that the nutritional profile of meat batter was enhanced by adding powdered pupae. Moreover, including pupae into the meat batter increased the hardness, chewiness, and gumminess of bug burgers. This important discovery was supported by other researchers who added mealworm larvae and silkworm pupae to

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emulsion sausages [10]. I am not sure whether increasing the gumminess of burgers or sausages is desirable or not, but if it is, insect ingredients certainly seem to be good at it. Our fundamental understanding of the behavior of different kinds of bug ingredients in foods during cooking is advancing. Proteins extracted from yellow mealworm larvae were reported to form a soft gel when heated [11], which may at least partially account for the increased gumminess of burgers and sausages when bug-based ingredients are added. Like real meat, insects contain proteins that unravel and coagulate when they are heated, leading to a more solid-like texture. A team of Belgian scientists examined the impact of replacing some of the meat in sausages with a “superworm” (Zophobas morio larvae) [12]. They chose this larvae species because it was found to have the best jellifying properties when heated. In addition, they decided to include the whole larvae, rather than the powdered form, because they felt this would give a meatier mouthfeel in the sausages. Unfortunately, the researchers found that the presence of the bug ingredients had a deleterious impact on the cookability and texture of the hybrid pork-bug products, highlighting the need for further research on these combo dishes. A group of Mexican scientists examined the possibility of replacing some of the meat in sausages with proteins extracted from a small grasshopper (Sphenarium purpurascens), which is commonly consumed in their country [13]. They found they could replace up to 5% of the meat with grasshopper protein without adversely affecting the desirable quality attributes of the sausage. This approach may therefore be one way of reducing the amount of meat eaten to create a more sustainable food supply. Moreover, this grasshopper is considered to be a plague by farmers because it destroys their crops. It would be fitting to turn an insect that is destroying our food into a food itself. In another study, the proteins in mealworms were reported to form a protective shell around the fat globules in foods [14], which may be useful for enhancing the fatty flavor and juicy mouthfeel of bug meat. Scientists have also examined the possibility of improving the quality of plant-based meat alternatives. A pair of Korean scientists showed that incorporating 30% of mealworm larva (Tenebrio molitor) into soy protein flour improved the nutritional value and taste of meat alternatives [15]. Bugs may therefore be used as ingredients in plant-based foods to make them meatier. In an article published in the International Journal of Gastronomy and Food Science, a scientist from the Culinary School of America examined the impact of cooking method on the properties of cricket broth [16]. The crickets were either frozen before being cooked or they were simply cooked alive. The broths were then fed to a group of 59 people who were asked to rank their

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sensory attributes like salty, bitter, sweet, sour, and savory, as well as their overall liking of the broths. The broth that had been prepared from crickets that were cooked alive was more salty, savory, and desirable, which was attributed to different chemical reactions occurring in the insects when they were cooked dead or alive. The author claims that this kind of knowledge is critical for creating bug-based foods that consumers will find desirable. Like real meat, insects can be cooked in many different ways. For instance, mealworms can be grilled, roasted, fried, boiled, steamed, or microwaved [17]. Each of these cooking methods causes different changes in the texture, mouthfeel, taste, and aroma of the insects, which is not fully understood. A study by a team of Italian scientists found that the method used to cook mealworms influences their nutritional value [18]. They examined the impact of baking, frying, boiling, steaming, or microwaving on the digestibility of the proteins and fats in the mealworms. Cooking in an oven was found to give the best protein digestibility, while deep frying was found to give the worst. The authors concluded that “mealworm larvae surely meet human nutritional requirements, but the cooking method must be carefully chosen to maintain a high nutritional value.” These studies show that before insects can be successfully incorporated into our diet, a lot more scientific and culinary research is needed to understand how they behave in foods. This knowledge could then be used to create bug-­ based foods most of us want to eat and that are better for us.

But Would You Eat It? The Yuck Factor One of the greatest hurdles to the widespread adoption of insects as foods is the “Yuck Factor.” Many people simply find the idea of eating bugs repulsive. Moreover, they are unwilling to try them because they are unfamiliar with insects as foods. Consequently, consumer scientists are carrying out research to establish which factors influence our reactions to bug-based foods, and how we can use this knowledge to overcome people’s aversion to trying and accepting them.

The Power of Expectation Prof. Stieger and his colleagues from Wageningen University in the Netherlands hypothesized that the perceived quality and acceptability of bug-based foods depends on their cultural appropriateness  – whether they are already

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commonly accepted as desirable foods in a particular society [19]. These Dutch scientists designed an ingenious experiment to test their hypothesis. They fed a group of test subjects four kinds of burgers labeled “beef burger,” “mealworm burger,” “frog meat burger,” or “lamb brain burger.” In reality, all the burgers only contained minced beef, breadcrumbs, tofu, and hazelnuts, but in different ratios, so as to create products with different textures and mouthfeels. The consumers were then given the four types of burgers in random order, so there was no correlation between the burger they were tasting and the unusual ingredient it was claimed to contain. The consumers were then asked to rank the burgers before and after eating them in terms of their “food appropriateness” and “overall liking.” Before eating, the “bug” burgers were ranked well below the regular burgers in terms of their appropriateness and liking. After eating, however, they were reported to have a similar overall liking as the real hamburgers but were still ranked much lower in terms of appropriateness. This study suggests that even if people find the taste of a product to be acceptable or desirable, they may still not eat it because they think it is culturally inappropriate. In another study, researchers videoed the facial expressions of test subjects while they were eating snack foods they were told contained either “protein” or “insect protein,” but were actually just potato chips [20]. Those told that the snacks contained insect protein had less positive and more negative facial expressions. Even so, the consumers reported liking all the products similarly by the end of the test, regardless of whether they were supposed to contain insect protein or not. Again, this study highlighted the importance of our preconceptions on our enjoyment of foods. If we have a negative perception of eating bugs, then we are less likely to eat them again, even if they taste good.

Bug Burger Taste Tests The studies that I just discussed fed test subjects foods that did not actually contain any insects. Instead, they were designed to test the impact of people’s expectations on their willingness to try and like bug-based foods. These studies do not determine how different kinds of bugs are perceived when we eat them. Soft juicy grubs and hard crispy crickets break down differently inside our mouths, releasing bodily fluids and body parts that are sensed differently on our tongues, leading to a different gastronomic experience. For this reason, scientists have also fed different kinds of bug-based foods to consumers to find out how much they liked them (or not).

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A team of scientists in Belgium compared the sensory and emotional responses of people to bug-, plant-, and meat-based burgers [21]. The consumers were asked to consume the burgers in three ways: (i) blind – the person did not know what type of burger they were eating; (ii) expected – the person was told what type of burger they were eating and asked to rank it before eating; and (iii) informed, the person was told what type of burger it was and asked to rank it after eating. The consumers gave scores for the overall liking, perceived quality, and nutritional value of each burger (Fig. 8.5). The meat burger was liked much better than the bug- or plant-based burgers, probably because the people tasting the burger were most familiar with this type of product and assumed it is what a good burger should taste like. Surprisingly, people liked the bug burgers more after eating them when they knew they contained insects than when they didn’t know. This suggests people were taking other factors into account in addition to taste, such as the potential ethical and environmental benefits of consuming insects. The relatively low ranking of the bug burger in the blind taste test suggests its quality was not very high. In future, food companies will have to create bug-based foods that look and taste delicious; otherwise consumers are unlikely to overcome their natural aversion to eating insects. Interestingly, people ranked the nutritional value of the bug burger significantly higher than that of the meat burger. This knowledge may help governments and food companies to craft 7

Blind (not told) Expected (told before)

Liking

6

Informed (told after)

5 4 3 2

Meat

Plant

Insect

Burger Type Fig. 8.5  Impact of burger type (meat, plant, or insect) on their sensory liking. (Figures drawn from data taken from Schouteten et al. [21])

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Meat

Plant

Aftertaste

Aftertaste Brown color

Soft

Dry

Salty

Granular

Off Flavor

Homogeneous

Nutty Flavor Juicy

Meat Flavor Meat Aroma

Insect Aftertaste Brown color

Soft

Dry

Salty

Granular

Off Flavor

Homogeneous

Nutty Flavor Juicy

Meat Flavor Meat Aroma

Brown color

Soft

Dry

Salty

Granular

Off Flavor

Homogeneous

Nutty Flavor Meat Flavor

Juicy Meat Aroma

Fig. 8.6  Impact of burger type (meat, plant, or insect) on their sensory profile. (Figures drawn from data taken from Schouteten et al. [21]. Images: Creative Commons – see Figure Permissions)

marketing campaigns for bug-based foods. An analysis of the sensory qualities of the three kinds of burgers, including brownness, juiciness, meaty aroma, nutty flavor, granularity, and softness, showed that they all had their own unique flavor profiles (Fig.  8.6). Although this study provides some useful insights, we have to be careful not to generalize too much from the results. Only a small number of products were tested on a small number of people: young adults from Belgium.

Why Don’t We Like Eating Bugs? Researchers have tried to find out why many of us in the West have such a strong aversion to eating insects [22]. They focused on two key concepts: neophobia – the fear of eating new or novel foods and disgust – the negative emotional response linked to some foods. Both neophobia and disgust may be hardwired into our brains through evolution because they protected our ancestors from eating foods that might make them sick. It is important to distinguish between these two seemingly similar concepts. Some foods are familiar to us, but we still find them disgusting – I hate lobsters and oysters. Other foods do not appear disgusting, but we still have a fear of eating them because we are unfamiliar with them. On a trip to Thailand, I came across some strange but beautiful-looking fruits in a local market that looked delicious, but I was reluctant to try them because I did not know what they were, how to eat them, or if they were safe. My more adventurous German

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colleague, Professor Jochen Weiss, did try them and ended up with diarrhea for the rest of the trip. The extent of fear and disgust for a particular food varies between individuals but is also culturally determined. Many people in Asian, African, and Central American countries love insect foods, whereas most people in Western countries find them disgusting. This may be because those of us who have been brought up in the West associate insects with feces, decaying matter, and disease [22]. Disgust was found to be a much more important factor in determining someone’s aversion to bug-based foods than neophobia. Even when people become more familiar with bug-based foods, they may still not want to consume them. This appears to have happened in several European countries, where insect burgers have been available in supermarkets for several years, but their widespread consumption has not increased. In future, it will be important for governments and food companies to change people’s negative attitudes (disgust) towards eating insects, preferably at a young age. Otherwise, bug-based foods will never be consumed at a level that could substantially reduce the amount of meat in our diets and so have beneficial environmental effects.

Changing Minds, Changing Palates The food industry seems to have a lot of work cut out to tackle bug aversion in Western countries. Social scientists have therefore been trying to understand how to persuade more consumers in Europe and North America to become bug eaters [6, 23, 24]. They found that people are more likely to eat insect-enriched foods if they were tasty, affordable, familiar, and prepared by somebody else (like a restaurant or a food company). They also found that people are more likely to eat insects if they are hidden in a familiar food, rather than eating a whole or clearly visible insect. Eating a pizza containing insect flour hidden in the dough is more acceptable than eating one with insects swimming through the tomato sauce. Moreover, people’s tendency to eat insects increases when they know they are better for their health and the environment. Consequently, including more information about the positive impacts of eating insects on food labels may drive more consumers to try and adopt them. A Dutch scientist recently argued that we must go from trying to find out what makes bug-based foods acceptable, to what makes them desirable [25]. People may be willing to try insects once, but for them to regularly incorporate them into their diet, it is important they actually enjoy eating them and have a compelling reason to make them part of their diet. This

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could be achieved by creating a more glamorous or meaningful eating experience, such as serving bugs as part of an exotic ethnic dish or highlighting some benefit to the environment or workers (like has been done with some high-­ end coffees and chocolates). It is important to provide an experience or story that is tailored to the specific culture where the bug-based foods are consumed. Some studies suggest that men are less averse to eating whole bugs than women, which was attributed to either the greater disgust sensitivity of women or sensation-seeking behavior of men [6]. However, there is no difference between men and women once the bugs are ground up and disguised in a familiar food product. Age also seems to play some role. Younger children and older adults appear to be less receptive to accepting bug-based foods than people between about 15 and 35. Educational level doesn’t play a major role, but more highly educated people seem to be slightly more receptive to tasting and accepting bug-based foods. This kind of information is important to food companies trying to craft advertising and marketing campaigns for targeted groups.

We Shall Overcome Historical records of food consumption suggest our strong aversion to eating bugs can be overcome. In the past, we have learned to love foods we previously spurned. In seventeenth-century New England, lobsters were so abundant that people walking along the beach would often come across two-foot-high piles of them. Back then, however, they were considered to be a trash food that was only suitable for the poor, servants, and prisoners. Now, they are considered a delicacy, and their harvesting, processing, and sale is worth over half a billion dollars. Lobsters have gone from pariah to prince. As Greg Elwell put it in the Oklahoma Gazette: “Lobster is fancy. If you imagine a lobster talking, it probably has a British accent. Draw an animated lobster and I bet you’ll include a top hat, a monocle, and an opera cape.” Personally, I have never been enamored by the charm of lobsters and have always considered them to be giant sea cockroaches. If people can enjoy these alarming looking sea bugs, then they may learn to love their terrestrial cousins. My feelings are similar about oysters, whelks, shrimps, and prawns; if these are considered delicacies now, why not cockroaches, grubs, and locusts in the future. So how did the lowly lobster become so desirable? The American journalist Daniel Luzeru has reported on the history of lobster eating [26]. Up until the late nineteenth century, lobster was abundant in New England and usually

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sold in cans as a cheap food. However, around the same time, railways developed and spread across the country. Lobsters were abundant and inexpensive and so made a good source of food aboard the trains. People from inland did not know that lobsters were considered to be trash food on the coast. Instead, they saw them as a rare and exotic delicacy. Moreover, restaurants were starting to cook lobsters live, rather than serving them from cans, which meant they tasted much better. The New England lobster industry was so successful at catching and canning lobsters that their numbers dwindled precipitously. As a result, they became a much rarer and more expensive food, which only added to their desirability. Perhaps a similar thing will happen to bugs. Instead of the iconic lobster rolls that are so popular in the coastal towns of New England now, people will be queuing up to pay exorbitant prices for cockroach rolls.

We Are All Entomophagists Anyway Although many of us are disgusted at the thought of eating bugs, we probably do it already, either consciously or unconsciously. Honey is made by bees who collect, regurgitate, digest, and then store nectar in their honeycombs. Cochineal is a bright red food dye extracted from a species of highly pigmented insect that is widely used in candies, yogurts, and beverages [14]. Shellac is a resin secreted by the female lac bug found in the forests of India and Thailand, which is commonly used as a coating on candies, ice cream cones, and jellybeans. If you opened your pantry or fridge and carefully looked through the food there, you are likely to find large numbers of insects or insect parts. In the United States, the Food and Drug Administration allows a certain number of insect parts in specific food products: up to 20 maggots per 100 g of mushrooms, 35 fruit fly eggs per 230 g of golden raisins, 4 larvae per 500  g of Brussel sprouts, and 225 insect fragments per 225 grams of macaroni. We are all already entomophagists.

Bug Farming: Mini-livestock If edible insects are ever going to compete with livestock animals as an affordable, nutritious, and sustainable source of meat, they will have to be produced economically on a large scale [1, 2, 27]. According to the United Nations, the world currently produces a staggering 340 million tonnes (740 billion pounds) of meat a year. To make any dent in this meat mountain, the edible insect

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industry needs to produce bug-based foods on this vast scale. According to recent market research, around 3.1  million tonnes of edible insects will be produced by 2030, with a market value of around $9.6 billion [28]. Most of these insects will be used to feed pets, fish, or livestock animals, but some of them will be used to feed humans. Even if all the edible insects produced were used as human food, they would still make up less than 1% of the food produced by livestock animals. Clearly, if bugs do become an acceptable alternative to meat, then the edible insect industry will need to greatly scale up its farming and processing facilities. Edible insects can be collected from the wild, but more typically they are grown in small- or large-scale bug farms. On farms, the insects are housed and fed in carefully controlled environments until they grow to a sufficient size. They are then washed to remove any feces and dirt, heat-treated to inactive any enzymes and microbes, and then dried to increase their shelf life. Some of the larger farms are highly automated facilities that house billions of insects and are capable of producing thousands of tonnes of edible insects a year. There are several factors that need to be considered when selecting a suitable insect species for mass production [29]. The bugs should grow quickly, be easy to maintain, cheap to feed, and be capable of living in a highly crowded environment without cannibalizing their neighbors. Some of the most common edible insects that meet these criteria are crickets, mealworms, grasshoppers, ants, and silkworms. At present, there are over a trillion insects being raised as animal or human food every year. The countries that raise the most insects are Thailand, France, South Africa, China, Canada, and the United States. Bug-based meats must also be affordable, delicious, convenient, and safe if they are ever going to compete with real meat. When bug-based meat products have been introduced into our supermarkets and restaurants, they have usually been more expensive than real meat, which has limited the number of people who are even willing to try them. This is partly because this is such a new segment of the food industry that companies are still optimizing their formulations and manufacturing processes. Moreover, the cost would come down if the market for bug-based meats increased, due to benefits linked to economies of scale. However, the market will not increase unless more people buy them. It seems like a “which came first the chicken or the egg?” problem (or perhaps “moth or the pupae” problem in this case).

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Is Eating Bugs Good for the Environment? Although many people in the West currently find eating bugs disgusting, they may be persuaded to give them a try if they thought it was much better for the environment. So how convincing is the scientific evidence for the environmental benefits of bug eating? There is strong evidence from numerous studies that replacing animal meat with bug meat does have environmental benefits. The raising and processing of edible insects produces less greenhouse gasses and pollution than the conventional livestock industry, as well as requiring less land and water (Table 8.1). Compared to beef, bugs require 5 times less water and 11 times less land to produce, while generating 6 times less greenhouse gas emissions. This is partly because bugs are much more efficient at converting their feed into protein than cows and because we eat much more of a bug’s body. Moreover, bugs need very little water to survive and grow, and they can be raised in highly confined spaces. Eating bugs could therefore be an important way of tackling climate change, reducing environmental damage, and combating biodiversity loss. Concerns have been raised about the sustainability of some sources of edible insects, usually those that are harvested from the wild, rather than raised in bug farms. In certain countries, the overexploitation of these insects has led to reductions in biodiversity because they are part of complex ecosystems. As highlighted by the United Nations, this has happened with certain kinds of grubs and ants in Australia, caterpillars in Zimbabwe, and several insect species in Mexico [29]. Conversely, insects that normally destroy human crops, such as grasshoppers and locusts, could be turned into foods themselves. Rather than treating the crops with chemical pesticides, these insects could be harvested and eaten. This practice would have environmental, economic, and nutritional advantages over current practices. There are less problems associated with biodiversity for farmed insects. However, it is still important to consider any potential impacts on the environment linked to raising insects on bug farms. If the bugs escaped and multiplied, they could pester people, Table 8.1  Environmental impacts of edible insects compared to livestock animals Food source

Feed Edible conversion share (%) factor

Global warming potential (CO2 eq)

Land use (m2/ Water use kg protein) (L/g protein)

Cattle Pigs Chicken Bugs

40 55 55 80

88 27 19 14

201 55 47 18

25 9.1 4.5 2.1

Data from FAO, United Nations report [29]

112 57 34 23

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consume nearby crops and sensitive plant species, and alter the ecological balance. For these reasons, many countries are introducing new regulations to govern the raising, containment, and killing of edible insects. Another environmental benefit of raising edible insects in farms is that they can convert organic waste products into nutritious foods for humans or animals [30]. These waste products are often sidestreams from food production, such as agricultural byproducts, manure, or food waste. For instance, waste arising from the production and distribution of fruits, vegetables, bread, beer, or wine can be fed to edible insects. This waste is usually inexpensive and nutrient dense, containing proteins, carbohydrates, fats, vitamins, and minerals, but is unfit for human consumption. Moreover, the waste products do not need to be incinerated or disposed of in landfill and so the level of pollution is reduced. Edible insects can therefore become a valuable element of a circular economy, where the minimum amount of the Earth’s valuable resources is exploited and wasted.

Is Bug-Based Meat Healthier for Us? Consuming bugs is healthier for the planet, but is it healthier for us? The healthiness of a food depends on the nutrients it contains, such as proteins, carbohydrates, fats, fibers, vitamins, and minerals. Some of these nutrients are beneficial to our health, others are detrimental. It is, therefore, useful to compare the nutritional content of traditional meats, such as beef, pork, lamb, and chicken, with those of insects (Table  8.2). The meat from traditional livestock is a good source of high-quality protein [5], as well as micronutrients essential to our health, such as vitamins and minerals (especially iron). Conversely, it may also contain high levels of saturated fats that have been linked to adverse effects on our health. The nutrient profile of insects depends on the species, development stage (larvae versus adult), and food processing used. Many insect species contain high levels of proteins, unsaturated fats, dietary fibers, vitamins, and minerals, and so are nutritious alternatives to meat (Table  8.2). Indeed, insects tend to contain higher levels of calcium, iron, vitamin C, and dietary fiber than animal meat. In one study, crickets, palm weevils, and mealworms were reported to have similar or better nutritional profiles than traditional meats [31]. Overall, the nutritional profile of edible bugs depends on the species, their life stage, and how they are prepared and is fairly similar to that found in animal meat. Consequently, there are unlikely to be any adverse nutritional consequences to switching from real meat to bug meat.

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Table 8.2  Comparison of main nutritional components in animal, plant, and insect

Food Beef Pork Chicken Lamb Crickets (adult) Crickets (larvae) Mealworm Mopane caterpillar Snout moth

Protein Fat (g) (g)

Vit Vit Fiber Cholesterol A B12 Vit Vit (g) (mg) (μg) (μg) C E

Calcium Iron (mg) (mg)

20.1 16.9 21.5 15.1 20.5

3.5 7.1 1.3 15.1 5.1

0 0 0 0 4.6

59 50 58 66 99

11.0 0.0 6.0 44.5 6.5

1.40 0.57 0.4 0.84 0.53

4.0 4.1 5.0 8.4 99.6

3.1 0.9 0.4 2.3 7.1

16.5

6.2

2.3

–