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| Fig. 1: GHG emission of beef as compared to other sources of protein, in global warming equivalent kg of CO2 per kg of meat product. Beef is the most emissive protein by far. Emission for beef is from Mattick et al., and the rest are from Swain et al. [4,10] (Source: T. Dyson) |
Meat production accounted for 14.5% of all greenhouse gas (GHG) emissions caused by humans in 2004. [1] As the population continues to rise, we can expect demand for meat to increase even further in the near future. Without a miraculous cultural shift, either towards plant-based substitutes or away from meat entirely, we seem destined for a climate disaster fueled by animal slaughter.
This problem is what lab-grown, or "cultured" meat aspires to solve. To produce traditional animal meat, you must birth, raise, and kill an entire animal. Cultured meat production, on the other hand, involves only growing the part we eat: the muscle and fat cells. A small sample of these cells is harvested harmlessly from an animal, then grown in nutrient-rich, heated bioreactors. The resulting slurry of muscle and fat cells is then arranged into a familiar meat structure, forming muscle fibers and fat pockets. The technology required to accomplish this task already exists. In 2013, a research team led by Post at Maastricht University created the first hamburger patty made from lab-grown beef muscle. [2]
Since the first academic proof of concept, the domain of cultured meat has exploded. The Good Food Institute (GFI), an international nonprofit focused on animal meat alternatives, reports that as of the end of 2020 there were over 70 cultured meat and seafood related companies, helping produce products from sushi to foie gras. [3] Many of these companies have small lab-scale production already in place. [3] Cultured meat has amassed $350 million in venture capital in total since 2016, with total investment almost doubling since last year. [3] Despite all this, no concrete timeline for commercially available cultured meat is presented. [3]
Here I will examine this promising new industry, detailing its potential impact and discussing the obstacles that lie between it and widespread commercial adoption.
This section discusses the practical and ethical impacts of cultured meat. The tangible advantages and disadvantages of cultured beef compared to animal beef are also quantified.
I choose to focus on beef because cows are incredibly inefficient, and thus full-cow beef is the type of meat the world would benefit most from replacing. Producing one kilogram of ground beef emits the same amount of GHGs on average as driving for 250 km in a typical gas car, consumes as much energy as powering the average American home for 2.9 hours (using total household energy use and census household count, and as much water as washing (Californian) dishes for 35 hours. [4-9] The GHG emission of beef as compared to other types of meat can be seen in Fig. 1.
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| Fig. 2: Comparison of several environmental impacts between animal- sourced and cultured beef. All quantities are given per kg of final meat product. Both animal and cultured beef GHG emission, energy consumption, and land use are from Mattick et al. [4] Animal beef water use is from Hoekstra. [8] Cultured beef water use is from Tuomisto et al. [11] (Source: T. Dyson) |
Since no company has yet succeeded at producing cultured meat at full commercial scale, a fair comparison with animal meat is difficult. Nonetheless, these are best estimates assuming current technology. As can be seen in Fig. 2, cultured beef emits less GHG and uses far less water and land than animal beef. [4,8,11] However, it uses more power (including that needed to produce feed in both the cultured and animal case). [4] Interestingly, an earlier study funded by cultured meat research group New Harvest, with consultation by Post himself, reports that cultured meat will take about a tenth of the land and a third of the energy given here, with consequentially smaller GHG emission. [11] I use that source for water use, so be warned. Further analysis reveals that most GHG emission from beef production is in the form of methane, which despite its potency as a GHG only persists in the atmosphere for a dozen years. [12] Cultured meat's emission comes mainly from electricity production in the form of carbon dioxide, which is more long-lived in the atmosphere, actually causing more global warming in the long term. [12] On the other hand, this means most of the GHG emission caused by cultured meat would be eliminated by using emission-free electricity.
If the practical climate, land, and resource argument isn't compelling enough, consider the ethical angle. Animal meat requires slaughtering large numbers of (usually) poorly treated animals, a fact that is repulsive to some and ignored by the rest. Cultured meat sidesteps this issue because a full animal is never grown. Therefore, it is true meat without the suffering of a whole living being.
This section discusses the obstacles in the way of this emerging technology. Since a small-scale proof of concept has already been produced, the remaining obstacles are largely social and economic.
For cultured meat to be a commercial success, first and foremost, people have to want to buy it. A study in Frontiers indicates that around 30% of people in the U.S. were very or extremely likely to purchase cultured meat, while another 47% were somewhat or moderately likely (with no mention of price). [13] Interestingly, people in China and India were much more receptive to cultivated meat adoption. [13] This study shows that a market exists, presumably under the condition of a comparable price to animal meat.
Before any cultivated meat can go on the market, however, it must be approved by governments around the world. In the U.S., the FDA and the USDA have outlined regulation for cultivated meat, and work is being done to solidify these plans. [3] In Singapore, the sale of Eat Just's GOOD Meat cultured chicken was approved in November of 2020, the first sale of cultured meat in the world. [14] The restaurant meal, consisting of a few well-presented chicken nuggets, sells for around $17 (U.S. dollars, at an unknown profit margin). [14]
With all this said, cultured meat shows promise. However, the largest hurdle yet remains: scaling up the production cost-effectively. Several factors are limiting cheap large scale cultured meat production. These arguments are taken from a report by Humbird funded by Open Philanthropy. [15] The GFI references Humbird in their State of the Industry Report, however they insist that no new technological developments are needed, and that cost reduction is inevitable. [3]
The first of Humbird's grievances is the need for a cheap and plentiful supply of nutrients for the cells. [15] Currently, such cell food is produced for pharmaceutical purposes, so is expensive and not produced in the vast quantities required have cultured meat supplant animal meat on the global market. [15] In fact, nutrients are the currently the most expensive part of cultured meat production. [15] On top of that, the most popular source for key biochemicals needed for proper cell growth is fetal bovine serum (FBS). [16] FBS is harvested (lethally) from unborn cattle after the mother is slaughtered. [16] A replacement for FBS will have to be found to keep the ethics people on cultured meat's side. Additionally, the cells' food would need to be extremely clean. In the case of animal meat, any trace toxins in the animal feed are (mostly) filtered out by the animal's liver, and do not end up in the muscle. However, for cultured meat, the cellular slurry inside the bioreactor has no liver, meaning any toxin left in the feed is put directly on your plate.
An effective scale-up of cultured meat production would also require an incredibly clean work environment. The warm, nutrient-rich bioreactor, ideal for animal cell growth, is also the perfect environment for pathogens (bacteria and viruses). If a single pathogen managed to get a foothold in the bioreactor, it would quickly overwhelm the animal cells, killing the entire batch. This restriction requires labs to be at least Class 6 cleanrooms. [15] Importantly, since that level of sanitation requires all pipes, windows, etc. to be perfectly sealed, as well as ventilation replacing the air 25 times an hour, they get much more expensive with size. Essentially, you can have a large factory or a clean factory. Cultured meat requires both. In animals, pathogens are mostly dealt with by the immune system. Since the cell slurry has no immune system, great care and expense must be invested to ensure the cells' safety.
The final problem I'll discuss is the limits on the size of the bioreactors. Larger bioreactors are more space-efficient, allowing you to have smaller cleanrooms, reducing those sanitation costs. However, larger bioreactors are also more susceptible to disease, since pathogens can ruin the entire batch. Beyond that cost balance lies another problem with larger bioreactors: waste management. When left to their own devices, cells build up waste products which slow down future cell growth. Cycling out this waste effectively is only possible in small bioreactors, requiring more reactors, therefore larger and much more expensive cleanrooms. [15] Another possible solution is to use slow-growing cell cultures, since they are more waste-efficient, however less frequent batches means again more reactors are required, again ratcheting up the price. [15] In animals, waste is extracted via blood vessels. Since cell cultures have no blood vessels, cell waste becomes a problem.
In all, Dr. Humbird's estimates that production costs come to about $37 per kg of cultured cells. [15] Compare this to $25 per kg of cells, the cost required for the derived ground meat product to reach about $50 per kg in grocery stores, competing with premium animal meats. [15] The price estimate is above that threshold, but not astronomically so.
Cultured meat is a rapidly growing new animal meat alternative. It has climate, resource, and ethical benefits over traditional animal meat. Studies show consumer acceptance is relatively high. Government bodies are working to put cultured meat regulations in place, and sale of one kind of cultured meat has already been approved in Singapore. The engineering involved in actually bringing production up to scale, however, is not yet figured out.
It's difficult to decide which sources to trust here. The GFI, with an interest in attracting investors, asserts that cultured meat is inevitable, that all costs will go down as technology marches on. [3] Is it true, though, that soon cultured meat will be a hundred-billion dollar industry, with aspirations of rivalling current animal meat, as they claim? And, most importantly, that now is the time to get on board, lest you miss the boat to money island? On the other hand, the lone Dr. Humbird's report paints a sobering picture. The engineering challenges involved in a cost-effective scale-up are not simple. The pharmaceutical industry has worked for decades with bioreactors, and a meagre 100 L reactor is considered ambitious even for high-throughput tasks such as coronavirus vaccines. [17] How can we expect the cultured meat industry, with a fraction of the funding, to increase bioreactor size well beyond that? Furthermore, will the costs of cell food really go down in the near future, as the GFI tacitly hopes?
It's easy to read either side of this debate and conclude that cultured meat will either be a wild success, supplanting animal meat forever, or a terrible failure once reality catches up and investors fail to see the returns promised. The truth is probably somewhere in the middle. Perhaps cultured meat will find its place as a premium-priced alternative protein for the environmentally or ethically conscious. The future of cultured meat is very much up in the air, and where exactly it will land will likely be decided within this decade.
© Taj Dyson. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] "Tackling Climate Change Through Livestock: A Global Assessment of Emissions and Mitigation Opportunities," Food and Agriculture Organization of the United Nations, 2013.
[2] M. J. Post, "Cultured Beef: Medical Technology To Produce Food," J. Sci. Food Agric. 94, 1039 (2014).
[3] "2020 State of the Industry Report: Cultivated Meat," The Good Food Institute, 2021.
[4] C. Mattick et al., "Anticipatory Life Cycle Analysis of In Vitro Biomass Cultivation for Cultured Meat Production in the United States," Environ. Sci. Technol. 49, 11941 (2015).
[5] T. Dyson, "Are Electric Cars Actually Better For the Climate Than Gas Ones?" Physics 240, Stanford University, Fall 2021.
[6] "Drivers of U.S. Household Energy Consumption, 1980-2009," U.S. Energy Information Administration, February 2015.
[7] M. Nord et al., "Household Food Security in the Unites States, 2009," U.S. Department of Agriculture, ERR-108, November 2010.
[8] A. Y. Hoekstra, "The Hidden Water Resource Use Behind Meat and Dairy," Anim. Front. 2, 3 (2012).
[9] "Plumbing Fixture Flow Rates, Residential Mandatory Measures: 2019 California Green Building Standards Code," City of Santa Monica, January 2020.
[10] M. Swain et al., "Reducing the Environmental Impact of Global Diets," Sci. Total Environ. 610-611, 1207 (2018).
[11] H. Tuomisto and M. Joost Teixeira de Mattos, "Environmental Impacts of Cultured Meat Production," Environ. Sci. Technol. 45, 6117 (2011).
[12] J. Lynch and R. Pierrehumbert, "Climate Impacts of Cultured Meat and Beef Cattle," Front. Sustain. Food Syst. 3, 5 (2019).
[13] C. Bryant et al., "A Survey of Consumer Perceptions of Plant-Based and Clean Meat in the USA, India, and China," Front. Sustain. Food Syst. 3, 11 (2019).
[14] M. Ives, "Singapore Approves a Lab-Grown Meat Product, a Global First," New York Times, 2 Dec 20.
[15] D. Humbird, "Scale-Up Economics for Cultured Meat," Biotechnol. Bioeng. 118, 3239 (2021).
[16] C. E. A. Jochems et al., "The Use of Fetal Bovine Serum: Ethical or Scientific Problem?" Altern. Lab. Anim. 30, 219 (2002).
[17] A. Offersgaard et al., "SARS-CoV-2 Production in a Scalable High Cell Density Bioreactor," Vaccines 9, 706 (2021).