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The eco‐friendly burger

2018; Springer Nature; Volume: 20; Issue: 1 Linguagem: Inglês

10.15252/embr.201847395

1469-3178

Hanna L. Tuomisto,

Meat and Animal Product Quality

Science & Society14 December 2018free access The eco-friendly burger Could cultured meat improve the environmental sustainability of meat products? Hanna L Tuomisto [email protected] Department of Agricultural Sciences and Helsinki Institute of Sustainability Science (HELSUS), University of Helsinki, Helsinki, Finland Search for more papers by this author Hanna L Tuomisto [email protected] Department of Agricultural Sciences and Helsinki Institute of Sustainability Science (HELSUS), University of Helsinki, Helsinki, Finland Search for more papers by this author Author Information Hanna L Tuomisto1 1Department of Agricultural Sciences and Helsinki Institute of Sustainability Science (HELSUS), University of Helsinki, Helsinki, Finland EMBO Rep (2019)20:e47395https://doi.org/10.15252/embr.201847395 Correction(s) for this article The eco-friendly burger12 March 2021 PDFDownload PDF of article text and main figures. ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InMendeleyWechatReddit Figures & Info Humanity is facing the twin challenge of producing sufficient and nutritious food for a growing and increasingly affluent population while reducing the environmental impact of agriculture. Livestock in particular is a major environmental stressor 1 as it produces an estimated 15% of global anthropogenic greenhouse gas (GHG) emissions 2, which is more than the whole transportation sector. The main sources of these emissions are methane from ruminants' enteric fermentation, emissions related to feed production, manure management and use of energy. In addition, cutting down forests for pasture and feed production substantially contributes to carbon dioxide emissions and biodiversity loss, especially in tropical regions. Livestock production also releases nitrogen and phosphorus into waterways, which causes eutrophication, disturbs ecosystems and can even result in oxygen depletion in lakes and oceans with drastic consequences for fish and other aquatic species. Lastly, livestock production consumes around a quarter of all fresh water available. Population growth and rising average incomes mean that the global demand for livestock products will further increase by up to 70% between 2010 and 2050… Population growth and rising average incomes mean that the global demand for livestock products will further increase by up to 70% between 2010 and 2050 2, which will have dramatic environmental consequences. However, the possibilities for increasing livestock production without increasing its environmental impact are very limited. Intensive livestock systems may help to use resources more efficiently and to better control emissions, but it has negative effects on animal welfare owing to limited space and cramped living conditions. Cultured meat has often been heralded as a silver bullet for solving the environmental problems caused by livestock production. One possible solution is substituting meat with plant-based alternatives 3. Nonetheless, despite the increasing availability and quality of vegetarian meat substitutes, the consumption of livestock products is still increasing. Dietary preferences change slowly as food consumption is tightly associated with complex social and cultural factors 4. The human preference for meat is also hard-wired as meat has a higher nutritional value than most crops, vegetables or fruits. This evolutionary predilection explains why eating meat provides more satisfaction compared to plant-based food and why so many people find it difficult to adopt a vegetarian diet. Recently, a range of plant-based products have become available that try to mimic the texture and consistency of meat to promise similar satisfaction. Yet, regardless of the increasing sophistication of these products, only a small percentage of consumers are willing to replace a substantial percentage of their meat consumption. In vitro agriculture Another response to the growing demand for meat has been the development of cellular agriculture—technologies based on tissue engineering and cell culturing—with the aim of growing cellular and acellular meat products in vitro. Cellular products consist largely of cultured, vat-grown meat—also known as in vitro meat, artificial meat, clean meat or cell-based meat—and fish, but also plant cells for food, cosmetics or other uses 5. Acellular products are proteins and other compounds synthesised by recombinant yeast, fungi or bacteria; these products include for instance milk and egg proteins, gelatine, fatty acids or sugars (Fig 1). Figure 1. The products of cellular agriculture can be distinguished into two types(i) Cellular products based on cell culture; (ii) acellular products that are synthesised by cultivated, recombinant microorganisms. Download figure Download PowerPoint The fermentation of microbes to produce individual molecules is much simpler than tissue engineering of mammalian cells and can be easily scaled up for commercial production. The technology is already used by the industry to produce food additives, enzymes and other compounds. One example is haem protein synthesised by yeast, which is used as a flavouring agent in vegetarian burgers to mimic the taste and colour of beef. … the nutrition medium should not contain any substances derived from animals, not only to reduce costs but also because it would defeat the purpose of replacing conventional animal products. In contrast, technologies for culturing of animal cells as food ingredients are still at the research stage, and scaling up the processes for commercial production requires major investments in research and development. During the past years, this has picked up pace and a few researchers and start-up companies have developed the first prototypes of cultured meat products, such as beef burgers, meatballs, chicken nuggets and even foie gras. Some companies estimate that their first products could become available for consumers in a few years. Cultured meat has often been heralded as a silver bullet for solving the environmental problems caused by livestock production. The answer to the question whether it could substantially improve the sustainability of food production systems depends on many factors. First, cultured meat production process would need to scale up in a cost-effective and resource-efficient way. Second, the total environmental impact of producing a unit of cultured meat would need to be lower than conventionally produced meat. Third, the production technology would require legal and regulatory approval and oversight. Finally, consumers' willingness to replace conventionally produced meat with cultured meat would be a key requirement to achieve its potential benefits. Vat-grown meat Cultured meat production starts by extracting adult muscle stem cells from a living animal or pluripotent stem cells from an embryo (Fig 2) 6. In theory, these cells can be obtained from any species, but the specifications of the production process are different for each. So far, researchers have been developing the technology for at least bovine, pig, turkey, chicken, duck and fish cells. Figure 2. The production process of cultured meatStem cells taken from muscle tissue or embryos are first expanded and then differentiated into muscle cells. These cells are further grown in a bioreactor to increase their number and can then be transferred to a matrix to grow these into muscle fibres and larger tissue. Download figure Download PowerPoint The stem cells are cultivated in a bioreactor under strict control of environmental factors. During the first step, the proliferation phase, the cells just multiply until they reach the desired concentration. The second step starts with differentiating the cells into muscle cells. After differentiation, they begin to merge and form myotubes that continue to grow into skeletal muscle tissue if the right conditions are provided. The structure of the meat product depends on the length and conditions of the production process. At the early stages of the differentiation phase, the cell culture consists of tiny and soft cell strands that require electric or mechanical stimulation to boost protein production, improve the structure and produce larger pieces of meat. In theory, it could even be possible to generate a steak-like structure; it would require a vascular system to deliver nutrients to the tissue. While cell culturing works on a smaller scale, many challenges need to be overcome to scale up cultured meat production. The main issues are the development of low-cost nutrition medium and optimising the design of bioreactors. The nutrition medium used in tissue engineering for medical purposes includes glucose and other nutrients, but also animal-based ingredients, such as bovine blood serum. To produce cultured meat, the nutrition medium should not contain any substances derived from animals, not only to reduce costs but also because it would defeat the purpose of replacing conventional animal products. Some culture media have been developed that do not contain blood serum or other animal-derived compounds, but those are not suitable for all cell types and are often less efficient in terms of cell growth and survival. Other alternatives to replace serum include cyanobacteria, algae, yeast and fungi, but further research is needed to develop cost-efficient options for all cell types and for different production stages, that is, proliferation and differentiation. Equally important is the design of the bioreactor so as to carefully control temperature, aeration and nutrient flow to the cell culture. In fact, the whole process requires more than one type of bioreactor given the different conditions required for proliferation and differentiation. The cells also need a surface to grow on, which means that the reactor has to include suitable scaffolding material. This can be made of an edible material, such as alginate or starch, and become a part of the final product or the cells can be harvested from the surface of the scaffold, or the scaffold can be removed at the end of the process. A potentially efficient option would be a hollow-fibre bioreactor that provides a suitable scaffold for the cells to grow on. Again, further research and development is needed to test whether such bioreactors would actually work for large-scale production, and whether it facilitates the formation of larger muscle tissues including sufficient stimulation for muscle growth. Environmental impact studies A couple of studies have attempted to provide preliminary estimates of the potential environmental impacts of large-scale production of cultured meat based on life cycle assessment (LCA) 789. Life cycle assessment is a method for estimating the environmental impacts of a product or service along the whole production process from extraction of resources up to waste management. An LCA study can include many environmental impact categories or it can concentrate only on a single impact. In the cases where the production system produces multiple outputs—a cow, for instance, produces milk, meat, pet food, leather, chemicals from fat and so on—the impacts of the whole process are shared between the co-products by using an allocation method based on economic values, mass, energy content or protein content of the products. Teixiera de Mattos and I estimated the environmental impact of cultured meat assuming a production process using cyanobacterial hydrolysate as a main component in the nutrition medium and a stirred-tank bioreactor with 60 days of production time 7. Our results showed that, when compared to European conventionally produced livestock meat, cultured meat had substantially lower GHG emissions, land requirements and water use. The energy usage was lower compared to conventional beef but higher compared to poultry (Fig 3). As this study relied on many assumptions regarding the bioreactor design, composition and amount of nutrition medium, the results are a preliminary rough estimate that identifies the main impacts and gives some insight to their order of magnitude. Figure 3. The environmental impact of different protein sourcesEnergy use (A), greenhouse gas emissions (B) and land use (C) 8. Download figure Download PowerPoint A conference paper by Ellis, Haastrup and me in 2014 presented estimates for cultured meat production in a hollow-fibre bioreactor using alternative nutrient sources such as cyanobacteria, wheat and maize 8. The 2011 paper used a water footprint method that included green water (rainwater), blue water (extracted surface- and ground water) and grey water (waste water), whereas the 2014 paper considered only blue water weighted with location-specific scarcity factors. While the 2011 paper allocated all impacts to meat production, the 2014 paper allocated 10% of the impacts of producing an animal to the co-products, such a skin, organs and fat, and 90% to meat. Overall, the 2014 paper showed higher environmental impacts compared to the 2011 estimates: the energy use of cultured beef was even higher than that of conventionally produced beef; GHG emissions were only slightly reduced compared to poultry; and water use was higher for poultry, but lower for beef, sheep and pork meat (Fig 3). Carolyn Mattick and colleagues assessed cultured meat produced in the USA based on currently available technologies 9. They assumed a stirred-tank bioreactor and growth medium based on corn as a main source of glucose. The paper differed from the earlier studies by including steam cleaning of the bioreactor between production cycles. Their results showed three times higher energy use compared to the previous estimates, which was explained by the steam cleaning, different composition of growth medium and different bioreactor design. When compared to conventionally produced livestock meat in the USA, they found higher GHG emissions compared to pork and poultry, but lower emissions compared to beef, whereas land use was substantially lower compared to livestock production (Fig 3). They also found that the risk of eutrophication—the enrichment of waterways with nutrients—of cultured meat was substantially lower compared to beef and pork, but not reduced for poultry. The authors also highlight the fact that, even though cultured meat production uses relatively large quantities of industrial energy, it requires less human edible energy as a form of feed than what is needed in livestock production. When comparing the environmental impacts of cultured meat with plant-based foods, the available estimates show that cultured meat has higher GHG emissions and energy use compared to unprocessed plant-based protein crops, such as beans and peas, but emissions are comparable with processed vegetarian meat substitutes 8. However, the environmental impact estimates of cultured meat are only available for unprocessed products; further processing would thus increase their impacts. Meat substitutes containing only plant material have lower GHG emissions than products containing milk and eggs. Confounding factors These three papers provide valuable insight into the potential environmental performance of cultured meat production on a larger scale, but also raise new questions. One common assumption of all estimates is a short cultivation time, which is not sufficient for growing larger structures of muscle tissue. The final product of the estimated processes is a loose cell mass that could be used for processed meat products. If the technology was used for producing larger pieces of meat, the cultivation time would be longer, which would also increase the resource requirements and the environmental impacts. Environmental impact assessment would also need to consider livestock co-products, such as leather, pet food, cosmetics, fertilisers and other chemicals. If cultured meat production would replace a substantial percentage of livestock production, these products would need to be produced by other, alternative technologies. The same applies with plant-based meat substitutes. As the cultured meat technologies are energy-intense, the source of energy plays a crucial role in determining the environmental burden. The studies described above assumed the use of the currently common sources of energy in the studied regions. The environmental impacts might therefore be substantially lower for low-emission energy sources. Cultured meat production would also use much less land than conventional production, which means that land area could be released for other uses, including for generating energy. It is likely that only a small proportion of the land area released from beef production would be enough to produce the energy required for running a cultured meat production facility, and the rest of the land area could be used for other purposes. Effects on ecosystems and biodiversity The overall environmental benefits of cultured meat production also depend on how the released land from livestock production would be utilised. For instance, if permanent pasturelands were converted for intensive crop production, the net impacts on climate change might even be negative: permanent pasturelands store large quantities of carbon in the soil and conversion of these lands to arable fields would release a substantial amount of the carbon into the air. In many areas, however, it would not be possible to convert grasslands to arable land; and the alternative use would be forest or native vegetation. In those cases, the conversion would increase the carbon stocks in the soil and vegetation and, therefore, result in even higher environmental benefits than what the simple product-level comparisons show. The biodiversity benefits of cultured meat also depend on how the land area released from livestock production would be used. Livestock production, especially extensive cattle grazing, maintains various habitats and species and is therefore beneficial for biodiversity. The same applies to rare local livestock breeds that would disappear without specific efforts to conserve them. In some areas, extensively grazed livestock also provides landscape benefits by keeping highlands clear from being forested. Thus, a complete elimination of all livestock production is not reasonable from the perspective of biodiversity conservation. Another argument for the importance of livestock in sustainable agricultural systems is their role in nutrient recycling and the ability to utilise plants that humans cannot consume as food. Cattle can graze on land areas that would not be suitable for food production, which plays an important role in regions where fertile cropland is a scarce resource. In addition, clover-grass ley is an important component in a sustainable crop rotation system: its large root biomass improves soil structure and increases soil carbon storage, and the plant fixes nitrogen from the atmosphere reducing the requirement for synthetic nitrogen fertilisers. In mixed livestock and crop rotation systems, ruminants utilise the ley crop as a feed and the manure can be used as a fertiliser for arable crops. Removal of livestock from the system would remove the need for the ley crop, which could lead to a decline of soil quality. However, biogas production could replace the cattle as a mean to recycle nutrients and provide financial incentives to using ley in crop rotation. The ley crop can be used as raw material in an anaerobic digester to produce biogas and the residue from the process can be applied as a fertiliser. In addition, the biogas energy could be used for running the bioreactors for cultured meat production. In this way, the cultured meat production could become part of a sustainable agricultural system. Wider adoption of the technology If it were possible to scale up cultured meat technology for commercial production in an economically feasible and environmentally sustainable way, the extent of the environmental benefits thus achieved would depend on the availability of the technology in different parts of the world and consumers' willingness to switch to cultured meat. Given the knowledge and expertise required and the high investment costs of the technology, it would be unlikely that cultured meat could benefit poor smallholder farmers in developing countries. However, with technology transfer programs, it could become a food source in the growing cities in third world countries. Environmental impact assessment would also need to consider livestock co-products, such as leather, pet food, cosmetics, fertilisers and other chemicals. A systematic review of consumers' perceptions of cultured meat showed that the main concerns are related to health, safety, taste and price, whereas animal welfare, environment and food security were seen as the major benefits 10. In theory, cultured meat could contain similar nutritional profile to conventionally produced meat, as the technology enables the tailoring of the nutritional content, for instance by adjusting the quantity and quality of fat. It would be possible to co-culture fat cells together with muscle the cells, or alternatively add fat at a later stage. The micronutrient profile in cultured meat could also be adjusted by adding nutrients in the growth medium or to the final product, which would achieve similar nutritional profile compared to livestock meat. Another argument for the importance of livestock in sustainable agricultural systems is their role in nutrient recycling and the ability to utilise plants that humans cannot consume as food. If the cultured meat technology was not able to produce products that resample meat in terms of consistency and taste any closer than plant-based meat substitutes already do, consumers' willingness might not be any higher than current interest in plant-based meat substitutes—or cultured meat could even have trouble competing with those products. Plant-based meat substitutes are constantly improving in terms of texture and taste, and some products are already hard to differentiate from meat. Especially when recombinant technologies for producing proteins become more widespread, high-quality meat replacements will become available. As cultured meat production is more resource intensive than the production of meat substitutes from plant and microbial proteins, it would need to provide some additional benefits to ensure that consumers would pay a higher price for it. Further reading Alexander P, Brown C, Arneth A, Dias C, Finnigan J, Moran D, Rounsevell MDA (2017) Could consumption of insects, cultured meat or imitation meat reduce global agricultural land use? Global Food Security 15: 22–32 Leroy F, Praet I (2015) Meat traditions. The co-evolution of humans and meat. Appetite 90: 200–211 Röös E, Bajželj B, Smith P, Patel M, Little D, Garnett T (2017) Greedy or needy? Land use and climate impacts of food in 2050 under different livestock futures. Global Environmental Change 47: 1–12 Shapiro P (2018) Clean meat. How growing meat without animals will revolutionize dinner and the world. Gallery Books Specht EA, Welch DR, Clayton EMR, Lagally CD (2018) Opportunities for applying biomedical production and manufacturing methods to the development of the clean meat industry. Biochemical Engineering Journal 132: 161–168 Stephens N, Dunsford I, Di Silvio L, Ellis M, Glencross A, Sexton A (2018) Bringing cultured meat to market: technical, socio-political, and regulatory challenges in Cellular Agriculture. Trends in Food Science & Technology 78: 155-166 Zaraska M (2016). Meathooked: the history and science of our 2.5-million-year obsession with meat. New York, NY: Basic Books … the extent of the environmental benefits thus achieved would depend on the availability of the technology in different parts of the world and consumers' willingness to switch to cultured meat. Cultured meat technology is still in the early stages and many problems need to be solved before it can be scaled up in a cost-efficient and environmentally sustainable way; it is therefore not prudent to rely on it to address the environmental burden of livestock production. While the development of the technology continues, efforts are also needed to improve the environmental performance of current crop and livestock production, to develop other alternatives to livestock products and to promote plant-based diets. It is crucial that environmental considerations are taken into account during the development of new food production technologies in order to guide the production processes towards sustainable solutions and to avoid negative consequential impacts. Conflict of interest The author declares that she has no conflict of interest. References 1. Campbell BM, Beare DJ, Bennett EM, Hall-Spencer JM, Ingram JSI, Jaramillo F, Ortiz R, Ramankutty N, Sayer JA, Shindell D (2017) Agriculture production as a major driver of the Earth system exceeding planetary boundaries. Ecol Soc 22: 8CrossrefWeb of Science®Google Scholar 2. Gerber PJ, Steinfeld H, Henderson B, Mottet A, Opio C, Dijkman J, Falcucci A, Tempio G (2013) Tackling climate change through livestock: a global assessment of emissions and mitigation opportunities. Rome, Italy: Food and Agriculture Organization of the United Nations (FAO)Google Scholar 3. Aleksandrowicz L, Green R, Joy EJ, Smith P, Haines A (2016) The impacts of dietary change on greenhouse gas emissions, land use, water use, and health: a systematic review. PLoS One 11: e0165797CrossrefPubMedWeb of Science®Google Scholar 4. Godfray HCJ, Aveyard P, Garnett T, Hall JW, Key TJ, Lorimer J, Pierrehumbert RT, Scarborough P, Springmann M, Jebb SA (2018) Meat consumption, health, and the environment. Science 361: eaam5324CrossrefPubMedWeb of Science®Google Scholar 5. Eibl R, Meier P, Stutz I, Schildberger D, Hühn T, Eibl D (2018) Plant cell culture technology in the cosmetics and food industries: current state and future trends. Appl Microbiol Biotechnol 102: 8661–8675CrossrefCASPubMedWeb of Science®Google Scholar 6. Post MJ (2012) Cultured meat from stem cells: challenges and prospects. Meat Sci 92: 297–301CrossrefPubMedWeb of Science®Google Scholar 7. Tuomisto HL, Teixeira de Mattos MJ (2011) Environmental impacts of cultured meat production. Environ Sci Technol 45: 6117–6123CrossrefCASPubMedWeb of Science®Google Scholar 8. Tuomisto HL, Ellis MJ, Haastrup P (2014) Environmental impacts of cultured meat: alternative production scenarios. Proceedings of the 9th International Conference on Life Cycle Assessment in the Agri-Food Sector. 19-21 October 2016, Dublin, Ireland.Google Scholar 9. Mattick CS, Landis AE, Allenby BR, Genovese NJ (2015) Anticipatory life cycle analysis of in vitro biomass cultivation for cultured meat production in the United States. Environ Sci Technol 49: 11941–11949CrossrefCASPubMedWeb of Science®Google Scholar 10. Bryant C, Barnett J (2018) Consumer acceptance of cultured meat: a systematic review. Meat Sci 143: 8–17CrossrefPubMedWeb of Science®Google Scholar Previous ArticleNext Article Read MoreAbout the coverClose modalView large imageVolume 20,Issue 1,January 2019Cover: Repurposed tamoxifen modulates the tumor microenvironment. Tamoxifen activates the G protein coupled estrogen receptor (GPER – in orange) in the plasma membrane. This activation triggers the regulation of two mechanotransduction pathways involving YAP and HIF‐1A and leads to stromal reprogramming via actomyosin contraction mediated mechanotransduction. These findings are included in two back to back studies in this issue (Cortes and colleagues). By Ernesto Cortes, Armando del Río Hernández and colleagues: “ GPER is a mechanoregulator of pancreatic stellate cells and the tumor microenvironment”, and “ Tamoxifen mechanically reprograms the tumor microenvironment via HIF/1A and reduces cancer survival.” Cover illustration by Carlos Matellan | Imperial College London. Volume 20Issue 11 January 2019In this issue FiguresReferencesRelatedDetailsLoading ...