By Clemence Blanchard
Cultured meat goes by many names – ‘cell-based meat’, ‘in vitro meat’, ‘clean meat’ – but the concept remains the same. While not entirely new, the application of tissue engineering and cell culturing techniques to replicate conventional meat from animal cells has gained traction in recent years, with the first in vitro beef burger patty made from cultured meat tested live on television in 2013 (Post, 2013). The technology promises to tackle issues in the way conventional meat is produced, with the main advantages ranging from sustainability and health to animal welfare (Post et al., 2020). Despite this, the challenges of upscaling cultured meat production along with public perception difficulties makes it hard to envisage a near future where cultured meat becomes a norm.
Edible meat tissue is complex but cultured meat simplifies it down to skeletal muscle tissue and an adipose tissue component (this is the ‘minimum’ to achieve cultured meat). Stem cells obtained from biopsies of living animals (which circumvents the killing of the animal) are stimulated to proliferate, generating more cells, and differentiate into muscle fibres or fat depending on the isolated stem cell type (Arshad et al., 2017; Post et al., 2020). There are two main techniques for cultured meat as outlined by Sharma, Singh Thind & Kaur (2015): scaffold-based and self-organising. The former produces ground/minced meat products (comprising the majority of cultured meat projects that have been undertaken) using either embryonic myoblasts or skeletal muscle satellite cells (adult stem cells of skeletal muscle). Following proliferation and differentiation, the cells are attached to a scaffold or carrier (to support the 3-D cell organisation) and are introduced to a bioreactor where they can fuse into myotubes and later form myofibers. Self-organising techniques aim to produce much more structured meat products like steak and increase in complexity.
One of the main motivators behind cultured meat is sustainability-based, aiming to reduce the consequences of industrial livestock farming practices – namely, land use, water consumption and greenhouse gas emissions (Post, 2012). For example, due to its intensive nature, livestock farming contributes 9% to carbon dioxide emissions, 39% to methane and 65% to nitrous oxide – though this is subject to variation depending on location in the world (FAO, 2006). Research shows that the world produces upwards of 3 times the quantity of meat compared to ~50 years ago (Ritchie & Roser, 2017) in part due to increasing population size, which continues to exacerbate the issue. Additionally, the Intergovernmental Panel on Climate Change recently highlighted that reducing conventional meat consumption would help mitigate the impacts of climate change (IPCC, 2019). However, the extent to which cultured meat, which only involves the growth of in vitro animal muscle tissue as opposed to the entire animal, can alleviate these issues is brought into question.
One anticipatory life cycle analysis (LCA) study by Tuomisto & Teixeira de Mattos (2011) found that greenhouse gas emissions were greatly reduced, water and land usage was substantially minimised and energy requirements were generally lower for the industrial scale production of cultured meat compared to conventional livestock farming. Other key advantages such as wildlife conservation and potential production of meat from currently overhunted species were also brought up. Contrary to this, another LCA study by Mattick et al. (2015) found that the energy consumption and global warming potential of cultured meat production were greater than anticipated, with industrial energy use higher for cultured meat than beef production. Unlike the previous study, Mattick et al. took into account that bioreactors have to be routinely cleaned for sterile purposes, and included basal media production for their feedstock (using a medium shown by prior studies to adequately support cell growth, as opposed to the cyanobacteria feedstock used by Tuomisto & Teixeira de Mattos which may not be sufficient for larger-scaled cell cultures). Depending on the different factors taken into account, estimates like global warming potential and energy use vary greatly, and it is difficult to decide whether one is ‘more accurate’ than the other – for example, a future shift towards cleaner energy sources could overcome the large energy requirements for cultured meat regardless (Lynch & Pierrehumbert, 2019).
Cultured meat is also predominantly in the research phase, with many technical challenges anticipated for the large-scale production of this meat: in order to produce the most cells with the least resources, scaffolds/carriers, bioreactors and cell culture media are all necessary. While scaffolds like microcarrier beads exist, there are many different requirements to take into consideration: scaffolds need to be stretchable for cell differentiation, flexible to prevent myotube detachment and edible, mimicking meat texture as best as possible (Edelman et al., 2005). Bioreactors use energy, and research into optimised bioreactors like packed-bed bioreactors (that can simultaneously serve as scaffolds with microcarriers) may require time and/or investment (Moritz, Verbruggen & Post, 2015). Cell culture medium has also been identified as one of the largest cost drivers – and consideration of the origin of the medium is important: bovine serum may be cheaper and more efficient but is animal-derived, defeating sustainability, animal welfare and health benefits (contamination risks) (Specht, 2020).
In spite of this, many see the advantages of cultured meat. In terms of health, the controlled, lab-based process of cultured meat production may slow the rise in antimicrobial resistance compared to livestock farming where mis-/overuse of antibiotics remains prevalent, by ensuring no antibiotics are present – though this may be futile by the time large-scale production is a possibility (Oliver, Murinda & Jayarao, 2010). Alternatively, this could be beneficial by preventing human pathogens like Salmonella, which are commonly transmitted through conventional meat (Painter et al., 2013). Others advocate for animal welfare, welcoming a process that reduces animal deaths.
Cultured meat is an undeniably exciting prospect. However, current technicalities in upscaling production and debates on its full sustainability potential bring into question whether we will see it in the market in the near future. This is even further complicated by public perception inputs (Macdiarmid, Douglas & Campbell, 2016): would you accept a change like this?
References:
Post, M.J. (2013) Cultured beef: medical technology to produce food. Journal of the Science of Food and Agriculture. 94 (6), 1039-1041. Available from: 10.1002/jsfa.6474
Post, M.J., Levenberg, S., Kaplan, D.L., Genovese, N., Fu, J., Bryant, C.J., Negowetti, N., Verzijden, K. & Moutsatsou, P. (2020) Scientific, sustainability and regulatory challenges of cultured meat. Nature Food. 1, 403-415. Available from: 10.1038/s43016-020-0112-z
Arshad, M.S., Javed, M., Sohaib, M., Saeed, F., Imran, A. & Amjad, Z. (2017) Tissue engineering approaches to develop cultured meat from cells: A mini review. Cogent Food & Agriculture. 3 (1), 1320814. Available from: 10.1080/23311932.2017.1320814
Sharma, S., Singh Thind, S. & Kaur, A. (2015) In vitro meat production system: why and how? Journal of Food Science and Technology. 52 (12), 7599-7607. Available from: 10.1007/s13197-015-1972-3
Post, M.J. (2012) Cultured meat from stem cells: Challenges and prospects. Meat Science. 92 (3), 297-301. Available from: 10.1016/j.meatsci.2012.04.008
FAO (2006) Livestock’s long shadow: environmental issues and options. Food and Agriculture Organisation of the United Nations. Available from: http://www.fao.org/3/a0701e/a0701e.pdf (Accessed 25/05/2021)
Ritchie, H. & Roser, M. (2017) Meat and Dairy production. Our World in Data. Available from: https://ourworldindata.org/meat-production#global-meat-production (Online Resource) (Accessed 25/05/2021)
IPCC (2019) Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems. Intergovernmental Panel on Climate Change. Available from: https://www.ipcc.ch/srccl/ (Accessed 25/05/2021)
Tuomisto, H.L. & Teixeira de Mattos, M.J. (2011) Environmental Impacts of Cultured Meat Production. Environmental Science and Technology. 45 (15), 6117-6123. Available from: 10.1021/es200130u
Mattick, C.S., Landis, A.E., Allenby, B.R. & Genovese, N.J. (2015) Anticipatory Life Cycle Analysis of In Vitro Biomass Cultivation for Cultured Meat Production in the United States. Environmental Science and Technology. 49 (19), 11941-11949. Available from: 10.1021/acs.est.5b01614
Lynch, J. & Pierrehumbert, R. (2019) Climate Impacts of Cultured Meat and Beef Cattle. Frontiers in Sustainable Food Systems. 3 (5). Available from: 10.3389/fsufs.2019.00005
Edelman, P.D., McFarland, D.C., Mironov, V.A. & Matheny, J.G. (2005) Commentary: In vitro-cultured meat production. Tissue Engineering. 11 (5-6), 659-662. Available from: 10.1089/ten.2005.11.659
Moritz, M.S., Verbruggen, S.E.L. & Post, M.J. (2014) Alternatives for large-scale production of cultured beef: A review. Journal of Integrative Agriculture. 14 (2), 208-216. Available from: 10.1016/S2095-3119(14)60889-3
Specht, L. (2020) An analysis of culture medium costs and production volume for cultivated meat. The Good Food Institute. Available from: https://gfi.org/wp-content/uploads/2021/01/clean-meat-production-volume-and-medium-cost.pdf (Accessed 25/05/2021)
Oliver, S.O., Murinda, S.E. & Jayarao, B.M. (2010) Impact of antibiotic use in adult dairy cows on antimicrobial resistance of veterinary and human pathogens: a comprehensive review. Foodborne Pathogens and Disease. 8 (3), 337-355. Available from: 10.1089/fpd.2010.0730
Painter, J.A., Hoekstra, R.M., Ayers, T., Tauxe, R.V., Braden, C.R., Angulo, F.J. & Griffin, P.M. (2013) Attribution of Foodborne Illnesses, Hospitalizations, and Deaths to Food Commodities by Using Outbreak Data, Unites States, 1998-2008. Emerging Infectious Diseases. 19 (3), 407-415. Available from: 10.3201/eid1903.111866
Macdiarmid, J.I., Douglas, F. & Campbell, J. (2016) Eating like there’s no tomorrow: Public awareness of the environmental impact of food and reluctance to eat less meat as part of a sustainable diet. Appetite. 96, 487-493. Available from: 10.1016/j.appet.2015.10.011
Imperial Bioscience Review 