Cultured meat, also known as cultivated meat among other names, is a form of cellular agriculture wherein meat is produced by culturing animal cells in vitro. This production method involves the molecularly identical growth of animal flesh, outside of a living animal. Cultured meat is produced using tissue engineering techniques pioneered in regenerative medicine. It is known for its potential to mitigate the environmental impact of meat production, as well as to address issues related to animal welfare, food security, and human health. Its potential has long been of interest, including to British statesman Winston Churchill in 1931.
Jason Matheny popularized the concept in the early 2000s after he co-authored a paper on cultured meat production and created New Harvest, the world's first non-profit organization dedicated to in vitro meat research. In 2013, Mark Post created a hamburger patty made from tissue grown outside of an animal; other cultured meat prototypes have gained media attention since. In 2020, SuperMeat opened a farm-to-fork restaurant in Tel Aviv called The Chicken, serving cultured chicken burgers in exchange for reviews to test consumer reaction rather than money; while the "world's first commercial sale of cell-cultured meat" occurred in December 2020 at Singapore restaurant 1880, where cultured chicken manufactured by United States firm Eat Just was sold. Most efforts focus on common meats such as pork, beef, and chicken; species which constitute the bulk of conventional meat consumption in developed countries. Some companies have pursued various species of fish and other seafood, such as Avant Meats who brought cultured grouper to market in 2021. Other companies such as Orbillion Bio have focused on high-end or unusual meats including elk, lamb, bison, and Wagyu beef. The production process of cultured meat is constantly evolving, driven by companies and research institutions. The applications for cultured meat have led to ethical, health, environmental, cultural, and economic discussions. Data published by The Good Food Institute found that in 2021 through 2023, cultured meat and seafood companies attracted over $2.5 billion in investment worldwide. However, cultured meat is not yet widely available. In January 2024, a study demonstrated that cow cells can produce their own growth factors and do not require the expensive recombinant growth factors or fetal bovine serum. In November 2025, a study demonstrated that cow cells can be spontaneously immortalized after 500 days without genetic modification, similar to how chicken cells are readily spontaneously immortalized in culture.
Nomenclature Besides cultured meat, the terms cultivated meat, clean meat, in vitro meat, cell-based meat, synthetic meat, slaughter-free meat, craft meat, healthy meat, and schmeat have been used to describe the product. Although it has multiple meanings, artificial meat is occasionally used. The term lab-grown meat has been used in news media, but has been criticized on the basis that as production reaches market-scale, it won't be grown in laboratories but rather larger-output facilities which Bruce Friedrich compares to "meat breweries". Between 2016 and 2019, clean meat gained traction. The Good Food Institute (GFI) coined the term in 2016, and in late 2018, the institute published research claiming that use of clean better reflected the production process and benefits. By 2018 it had surpassed cultured and in vitro in media mentions and Google searches. Some stakeholders in cultured meat production, seeking to work with conventional meat producers as allies, felt that the term clean meat unnecessarily tarnished the latter, and went on to prefer cell-based meat as a neutral alternative. In September 2019, GFI announced new research which found that the term cultivated meat is sufficiently descriptive and differentiating, possesses a high degree of neutrality, and ranks highly for consumer appeal. A September 2021 poll indicated that the majority of industry CEOs have a preference for cultivated meat, with 75 percent of 44 companies preferring it.
History
Initial research The theoretical possibility of growing meat in an industrial setting has long been of interest. In a 1931 essay published by various periodicals and later included in his work Thoughts and Adventures, British statesman Winston Churchill wrote: "We shall escape the absurdity of growing a whole chicken to eat the breast or wing, by growing these parts separately under a suitable medium." In the 1950s, Dutch researcher Willem van Eelen independently came up with the idea for cultured meat. As a prisoner of war during the Second World War, Van Eelen suffered from starvation, leaving him passionate about food production and food security. He attended a university lecture discussing the prospects of preserved meat. The earlier discovery of cell lines provided the basis for the idea. In vitro cultivation of muscle fibers was first performed successfully in 1971 when pathologist Russell Ross cultured guinea pig aorta. However, In 1991, Jon F. Vein secured patent US 6835390 for the production of tissue-engineered meat for human consumption, wherein muscle and fat would be grown in an integrated fashion to create food products. In 2001, dermatologist Wiete Westerhof along with van Eelen and businessperson Willem van Kooten announced that they had filed for a worldwide patent on a process to produce cultured meat. The process employed a matrix of collagen seeded with muscle cells bathed in a nutritious solution and induced to divide. That same year, NASA began conducting cultured meat experiments, with the intent of allowing astronauts to grow meat instead of transporting it. In partnership with Morris Benjaminson, they cultivated goldfish and turkey. In 2003, Oron Catts and Ionat Zurr exhibited a few centimeters of "steak", grown from frog stem cells, which they cooked and ate. The goal was to start a conversation surrounding the ethics of cultured meat—"was it ever alive?", "was it ever killed?", "is it in any way disrespectful to an animal to throw it away?" In the early 2000s, American public health student Jason Matheny traveled to India and visited a factory chicken farm. Appalled by the implications of this system, he later teamed up with three scientists involved in NASA's efforts. In 2004, Matheny founded New Harvest to encourage development by funding research. In 2005, Jason Matheny, Pieter Edelman, Douglas McFarland & Vladimir Mironov published the first peer-reviewed literature on the subject (In vitro cultured meat production) in Tissue Engineering. In May 2008, PETA offered a $1 million prize to the first company to bring cultured chicken meat to consumers by 2012. The contestant was required to complete two tasks to earn the prize, namely to produce a cultured chicken meat product that was indistinguishable from real chicken and produce the product in large enough quantities to be competitively sold in at least 10 states. The contest was later extended until 4 March 2014. The deadline eventually expired without a winner. The Dutch government has invested $4 million into experiments regarding cultured meat. The In Vitro Meat Consortium, a group formed by international researchers, held the first international conference hosted by the Norwegian Food Research Institute in April 2008. Time magazine declared cultured meat production to be one of the 50 breakthrough ideas of 2009. In November 2009, scientists from the Netherlands announced they had managed to grow meat using cells from a live pig.
First public trial The first cultured beef burger patty was created by Mark Post at Maastricht University in 2013. It was made from over 20,000 thin strands of muscle tissue, cost over $325,000 and needed 2 years to produce. The burger was tested on live television in London on 5 August 2013. It was cooked by chef Richard McGeown of Couch's Great House Restaurant in Polperro, Cornwall, and tasted by critics Hanni Rützler, a food researcher from the Future Food Studio, and Josh Schonwald. Rützler stated, "There is really a bite to it, there is quite some flavour with the browning. I know there is no fat in it so I didn't really know how juicy it would be, but there is quite some intense taste; it's close to meat, it's not that juicy, but the consistency is perfect. This is meat to me... It's really something to bite on and I think the look is quite similar." Rützler added that even in a blind trial she would have taken the product for meat rather than a soya copy.
Industry development
Between 2011 and 2017, many cultured meat startups were launched. Memphis Meats, now known as Upside Foods, launched a video in February 2016, showcasing its cultured beef meatball. In March 2017, it showcased chicken tenders and duck a l'orange, the first cultured poultry shown to the public. An Israeli company, SuperMeat, cultured chicken. Finless Foods, a San Francisco-based company working on cultured fish, was founded in June 2016. In March 2017 it commenced laboratory operations. In March 2018, Eat Just (in 2011 founded as Hampton Creek in San Francisco, later known as Just, Inc.) claimed to be able to offer a consumer product from cultured meat by the end of 2018. According to CEO Josh Tetrick the technology was already there. JUST had about 130 employees and a research department of 55 scientists, where cultured meat from poultry, pork and beef was researched. JUST has received investments from Chinese billionaire Li Ka-shing, Yahoo! co-founder Jerry Yang and according to Tetrick also by Heineken International and others. Dutch startup Meatable, consisting of Krijn de Nood, Daan Luining, Ruud Out, Roger Pederson, Mark Kotter and Gordana Apic among others, reported in September 2018 that it had succeeded in growing meat using pluripotent stem cells from animal umbilical cords. Although such cells are reportedly difficult to work with, Meatable claimed to be able to direct them to behave to become muscle or fat cells as needed. The major advantage is that this technique bypasses fetal bovine serum, meaning that no animal has to be killed to produce meat. That month, an estimated 30 cultured meat startups operated across the world. IntegriCulture is a Japan-based company working on their CulNet system which is a platform that fosters innovation in cellular agriculture by using a feeder organ that works by naturally secreting growth factors that cell cultures need. Competitors included England based Multus Media and Canadian Future Fields. In August 2019, five American startups announced the formation of the Alliance for Meat, Poultry & Seafood Innovation (AMPS Innovation), a coalition seeking to work with regulators to create a pathway to market for cultured meat and seafood. The founding members include Eat Just, Memphis Meats, Finless Foods, BlueNalu, and Fork & Goode. Similarly in December 2021, a group of 13 European and Israeli companies (Aleph Farms, Bluu Biosciences, Cubiq Foods, Future Meat, Gourmey, Higher Steaks, Ivy Farm, Meatable, Mirai Foods, Mosa Meat, Peace of Meat, SuperMeat, and Vital Meat) established Cellular Agriculture Europe, a Belgium-based association that sought to 'find common ground and speak with a shared voice for the good of the industry, consumers, and regulators'. In October 2019, Aleph Farms collaborated with 3D Bioprinting Solutions to culture meat on the International Space Station. This was done by extruding meat cells onto a scaffold using a 3D printer. In January 2020, Quartz found around 30 cultured meat startups, and that Memphis Meats, Just Inc. and Future Meat Technologies were the most advanced because they were building pilot plants. According to New Scientist in May 2020, 60 start-ups were developing cultured meat. Some of these were technology suppliers. Growth media reportedly still cost "hundreds of dollars per litre, but for clean meat production to scale this needs to drop to around $1 a litre." In June 2020, Chinese government officials called for a national strategy to compete in cultured meat. In December 2019, the Foieture project was launched in Belgium with the goal of developing cultured foie gras (the name is a portmanteau of 'foie' and 'future') by a consortium of 3 companies (cultured-meat startup Peace of Meat, small meat-seasoning company Solina, and small pâté-producing company Nauta) and 3 non-profit institutes (university KU Leuven, food industry innovation centre Flanders Food, and Bio Base Europe Pilot Plant). Peace of Meat stated in December 2019 that it intended to complete its proof of concept in 2020, to produce its first prototype in 2022, and to go to market in 2023. That month, the Foieture project received a research grant of almost 3.6 million euros from the Innovation and Enterprise Agency of the Flemish Government. In May 2020, Peace of Meat's Austrian-born cofounder and scientific researcher Eva Sommer stated that the startup was then able to produce 20 grams of cultured fat at a cost of about 300 euros (€15,000/kg); the goal was to reduce the price to 6 euros per kilogram by 2030. Piece of Meat built two laboratories in the Port of Antwerp. In late 2020, MeaTech acquired Peace of Meat for 15 million euros, and announced in May 2021 that it would build a new large-scale pilot plant in Antwerp by 2022. In November 2020, Indian start-up Clear Meat claimed it had managed to cultivate chicken mince at the cost of only 800–850 Indian rupees (US$10.77–11.44), while a slaughtered processed chicken cost about 1,000 rupees. On 27 April 2022, the European Commission approved the request for the collection of signatures for the European Citizens' Initiative End The Slaughter Age to shift subsidies from animal husbandry to cellular agriculture. According to a November 2023 report by Oghma Partners, 46.9% of all funds – over 2.6 billion British pounds – raised for cultivated meat start-ups between 2016 and 2023 went to a top five, comprising Upside Foods (21.5%; formerly Memphis Meats), Believer Meats (formerly Future Meat Technologies), Wildtype, Aleph Farms, and Mosa Meat.
Market entry
Australia and New Zealand entry On 7 April 2025, Vow quail became the first cultured meat product to be officially approved for sale in Australia and New Zealand. In mid-June 2025, Vow expected to be serving its cultivated quail in restaurants in Sydney and Melbourne "within weeks".
European Union and Switzerland entry In the European Union, novel foods such as cultured meat products have to go through a testing period of about 18 months during which a company must prove to the European Food Safety Authority (EFSA) that their product is safe. In March 2022, cultured meat producers had reached the level of attempting to gain regulatory approval from European Union supranational institutions coming just before mass goods could be sold to consumers. By February 2023, none had yet submitted a novel food dossier for approval by the EFSA. Legal experts explained this as having to do with the fact that, although the EFSA's novel food procedure has been well-established since 1997 (unlike in other jurisdictions, that still have or had to develop certain regulatory standards), it is a long and complicated process in which companies can have little input once they have submitted their request, unlike cultured meat startups in the United States (who could easily communicate back and forth with the FDA to clarify any issues), and in the UK, Singapore and Israel (where governments have implemented a 'single point of contact' responsible for the overall process). Aleph Farms was the first start-up to apply for approval of its cultivated beef steaks in Switzerland in July 2023. While not part of the European Union, Switzerland was regarded as an important case study with great interest from legal scholars around the world, and expected to have widespread implications for the EU countries surrounding it. In April 2024, the Dutch start-up Meatable hosted the first legally approved public proof‑of‑concept tasting of cultured meat in the European Union - a sausage - following ad hoc approval by a national expert committee under a newly introduced Dutch code of practice. The event attracted significant national and international media attention. Meatable CTO Daan Luining cautioned it would take several years to scale up production to serve all supermarkets, that cultured meat was just an alternative that would gradually become more widely available, giving consumers more choices, and that the traditional meat industry would not be replaced any time soon. In July 2024, French startup Gourmey was the first company in Europe to apply for regulatory approval at the EFSA, followed by pioneer Mark Post's Mosa Meat from the Netherlands in January 2025. Just two weeks later, after securing 1.5 million euros in a crowdfunding campaign within 24 minutes, Mosa Meat teamed up with Swiss meat processor Bell Food Group to apply for regulatory approval for its cultivated beef fat in Switzerland as well, and in May 2025 it submitted its application at the Food Standards Agency in the United Kingdom.
Israel entry In November 2020, SuperMeat opened a test restaurant in Ness Ziona, Israel, right next to its pilot plant; journalists, experts and a small number of consumers could book an appointment to taste the novel food there, while looking through a glass window into the production facility on the other side. The restaurant was not yet fully open to the public, because as of June 2021 SuperMeat still needed to wait for regulatory approval to start mass production for public consumption, and because the COVID-19 pandemic restricted restaurant operations. By February 2023, Israeli authorities had established a regulatory structure similar to that of Singapore, and shown a general willingness to work towards approval (as well as financing research for cultivated food innovation), but were still in the process of developing safety regulations in consultations with researchers and other experts. For example, the Israeli Health Ministry and UN Food and Agriculture Organization (FAO) co-organised a convention of cultivated food safety regulation experts in September 2022. In January 2024, the Ministry of Health in Israel granted regulatory approval for cultured beef to Aleph Farms.
Singapore entry On 2 December 2020, the Singapore Food Agency approved the "chicken bites" produced by Eat Just for commercial sale. It marked the first time that a cultured meat product passed the safety review (which took 2 years) of a food regulator, and was widely regarded as a milestone for the industry. The chicken bits were scheduled for introduction in Singaporean restaurants. Restaurant "1880" became the first to serve cultured meat to customers on Saturday 19 December 2020. In January 2023, the SFA also granted regulatory approval for the production of cultured meat with serum-free media to Eat Just subsidiary GOOD Meat, which had introduced its cultivated chicken product in several more Singaporean restaurants as well as hawker centres and food delivery services since 2020, and was constructing the bioreactors for its new facility in Singapore. This world-first approval was said to be a milestone in making cultivated meat production more scalable and efficient. In April 2024, Australian start-up Vow obtained Singaporean approval for its cultured quail; while Dutch start-up Meatable would be introducing its cultivated pork sausages in several restaurants in Singapore later in 2024.
United States entry In November 2022, the Food and Drug Administration (FDA) completed the pre-market consultation of Upside Foods (formerly Memphis Meats), concluding that its products were safe to eat, a first for cultivated meat companies in the United States. Approval from the final agency, the United States Department of Agriculture (USDA) was received by Upside Foods and Good Meat, both for cultivated chicken, in June 2023. On 28 May 2025, Wildtype obtained regulatory approval from the FDA to sell its cultivated coho salmon (Oncorhynchus kisutch) product on the U.S. market. With that, Wildtype became the first start-up to be permitted to sell cultivated seafood in the United States, and a few days later, it was on the menu at the Kann restaurant of Gregory Gourdet in Portland, Oregon.
United Kingdom entry On 6 February 2025, it was announced that British pet food company THE PACK (acquired by Prefera Petfood in May 2025) would release the first commercially available product for pets containing cultivated chicken made by Meatly the following day.
Companies working on cultured meat
Process
Cell lines Cellular agriculture requires cell lines, generally stem cells. Stem cells are undifferentiated cells which have the potential to become many or all of the required kinds of specialized cell types. Totipotent stem cells have the capacity to differentiate into all the different cell types found within the body. Pluripotent stem cells can mature into all cell types save those in the placenta, and multipotent stem cells can differentiate into several specialized cell types within one lineage. Unipotent stem cells can differentiate into one specific cell fate.
While pluripotent stem cells would be an ideal source, the most prominent example of this subcategory is embryonic stem cells which—due to ethical issues—are controversial for use in research. As a result, scientists have developed induced pluripotent stem cells (iPSCs)—essentially multipotent blood and skin cells that have been regressed to a pluripotent state enabling them to differentiate into a greater range of cells. The alternative is using multipotent adult stem cells that give rise to muscle cell lineages or unipotent progenitors which differentiate into muscle cells. Favourable characteristics of stem cells include immortality, proliferative ability, unreliance on adherence, serum independence and easy differentiation into tissue. The natural presence of such characteristics are likely to differ across cell species and origin. As such, in vitro cultivation must be adjusted to fill the exact needs of a specific cell line. The immortality issue is that cells have a limit on the number of times they can divide that is dictated by their telomere cap—supplementary nucleotide bases added to the end of their chromosomes. With each division, the telomere cap progressively shortens until nothing remains, at which time the cells cease to divide. Induced pluripotency can lengthen telomere cap such that the cells divide indefinitely. Cell lines can be collected from a primary source, i.e., through a biopsy on an animal under local anesthesia. They could also be established from secondary sources such as cryopreserved cultures (cultures frozen after previous research).
Growth medium
Once cell lines are established, they are immersed in a culture medium to induce them to proliferate. Culture media are typically formulated from basal media that provide cells with necessary carbohydrates, fats, proteins and salts. Once a cell consumes a sufficient amount, it divides and the population increases exponentially. Culture media can be supplemented with additives—for instance sera—that supply additional growth factors. Growth factors can be secreted proteins or steroids that are crucial in regulating cellular processes. Once differentiation begins, muscle fibres begin to contract and generate lactic acid. Cells' ability to absorb nutrients and proliferate in part depends on the pH of their environment. As lactic acid accumulates within the medium, the environment will become progressively more acidic and falls below the optimal pH. As a result, culture media must be frequently refreshed. This helps refresh the concentration of nutrients from the basal media.
Scaffolds
In the case of structured meat products—products that are characterized by their overall configuration as well as cell type—cells must be seeded to scaffolds. Scaffolds are essentially molds meant to reflect and encourage the cells to organize into a larger structure. When cells develop in vivo, they are influenced by their interactions with the extracellular matrix (ECM). The ECM is the 3-dimensional mesh of glycoproteins, collagen and enzymes responsible for transmitting mechanical and biochemical cues to the cell. Scaffolds need to simulate the characteristics of the ECM.
Porosity Pores are minute openings on the surface of the scaffold. They can be created on the surface of the biomaterial in order to release cellular components that could interfere with tissue development. They also help diffuse gas and nutrients to the innermost layers of adherent cells, preventing a "necrotic center" from forming. A necrotic center is a phenomenon in which cells that are not in direct contact with the culture medium die from a lack of nutrients.
Vascularization Vascular tissue found in plants contains the organs responsible for internally transporting fluids. It forms natural topographies that provide a low cost way to promote cell alignment by replicating the natural physiological state of myoblasts. It may also help with gas and nutrient exchange.
Biochemical properties A scaffold's biochemical properties should be similar to those of the ECM. It must facilitate cell adhesion through textural qualities or chemical bonding. Additionally, it must produce the chemical cues that encourage cell differentiation. Alternatively, the material should be able to blend with other substances which have these functional qualities.
Crystallinity The degree of a material's crystallinity determines qualities such as rigidity. High crystallinity can be attributed to hydrogen bonding which in turn increases thermal stability, tensile strength (important for maintaining the scaffold's shape), water retention (important for hydrating the cells) and Young's modulus.
Degradation Certain materials degrade into compounds that are beneficial to cells, although this degradation can also be irrelevant or detrimental. Degradation allows easy removal of the scaffold from the finished product leaving only animal tissue—thereby increasing its resemblance to in vivo meat. This degradation can be induced by exposure to certain enzymes which do not impact the muscle tissue.
Edibility If scaffolds are unable to be removed from the animal tissue, they must be edible to ensure consumer safety. It would be beneficial if they were to be made out of nutritious ingredients. Since 2010, academic research groups and companies have been working to identify raw materials that have the characteristics of suitable scaffolds.
Cellulose Cellulose is the most abundant polymer in nature and provides the exoskeletons of plant leaves. Due to its abundance, it can be obtained at a relatively low cost. It is also versatile and biocompatible. Through a process called "decellularization", it is coated in a surfactant that creates pores. These pores release the plant's cellular components, and it becomes decellularized plant tissue. This material has been extensively studied by the Pelling and Gaudette Groups at University of Ottawa and Worcester Polytechnic Institute, respectively. Through cross-linking (forming covalent bonds between individual polymer chains to hold them together) the plant tissue's mechanical properties can be changed so that it more closely resembles muscle tissue. This can also be done by blending plant tissue with other materials. On the other hand, decellularized plant tissue typically lacks mammalian biochemical cues, so it needs to be coated with compensatory functional proteins. C2C12 growth was not shown to change significantly between the bare scaffold and the same scaffold with a coating of collagen or gelatin proteins; however, seeding efficiency (rate at which cells attach to the scaffold) improved. An advantage of decellularized plant tissue is the natural topography afforded by the leaf vasculature. This helps replicate the natural physiological state of the myoblasts which promotes cell alignment. The other ways of doing this are usually quite a bit more expensive including 3D printing, soft lithography and photolithography. Vascularization can also help overcome the 100–200 nm diffusion limit of culture medium into cells that usually produce necrotic centres in muscle conglomerates. Another way to do this is by having a porous scaffold which supports angiogenesis (the development of new blood vessels). While this has been shown to work for apple Hypanthium, not all plants are nearly as porous. The alternative to plant cellulose is bacterial cellulose which is typically more pure than plant cellulose as it is free from contaminants such as lignin and hemicellulose. Bacterial cellulose has more hydrogen bonding between its polymer strands and so it has greater crystallinity. It also has smaller microfibrils that allow it to retain more moisture and have smaller pores. The substance can be produced using waste carbohydrates (which may allow it to be produced less expensively) and it adds juiciness and chewiness to emulsified meat (which would mean that even if it can't be taken out of the final product, it will contribute to the texture profile). Decellularized plants that have been studied as possible scaffold materials include spinach, bamboo, algae, apple, celery, and Aloe vera.
Chitin Chitin is nature's second most abundant polymer. It is found in the exoskeletons of arthropods and fungi. As cellular agriculture is attempting to end reliance on animals, chitin derived from fungi is of greater interest. It has mostly been studied by Pelling Group. Chitosan is derived from chitin in a process known as alkaline deacetylation (substituting out certain amino acid groups). The degree of this process determines the physical and chemical properties of the chitosan. Chitosan has antibacterial properties; in particular, it has bactericidal effects on planktonic bacteria and biofilms and a bacteria static effects on gram negative bacteria such as E. coli. This is important as it neutralizes potentially harmful compounds without using antibiotics, which many consumers avoid. Chitosan's resemblance to glycosaminoglycans and internal interactions between glycoproteins and proteoglycans make it highly biocompatible. It can easily blend with other polymers in order to select for more bioactive factors. One potential disadvantage of chitosan is that it degrades in the presence of lysozymes (naturally occurring enzymes). But, this can be resisted using deacetylation. This is not entirely negative, as the byproducts produced through degradation have anti-inflammatory and anti-bacterial properties. It is important to match the level that cells rely on the matrix for structure with degradation.
Collagen Collagen is a family of proteins that makes up the primary structure of human connective tissue. It is typically derived from bovine, porcine and murine sources. Cellular agriculture overcomes this dependency through the use of transgenic organisms that are capable of producing the amino acid repeats that make up the collagen. Collagen naturally exists as collagen type I. It has been produced as porous hydrogels, composites and substrates with topographical cues and biochemical properties. Synthetic kinds of collagen have been produced through recombinant protein production—collagen type II and III, tropoelastin and fibronectin. One challenge with these proteins is that they can not be modified post translation. However, an alternative fibrillar protein has been isolated in microbes that lack collagen's biochemical cues, but has its kind of gene customizability. One focus of recombinant collagen production is yield optimization—how it can be produced most effectively. Plants, in particular, tobacco look like the best option, however, bacteria and yeast are also viable alternatives. Textured soy protein is a soy flour product often used in plant-based meat that supports the growth of bovine cells. Its spongy texture enables efficient cell seeding and its porosity encourages oxygen transfer. Additionally, it degrades during cell differentiation into compounds that are beneficial to certain cells.
Mycelium Mycelium are the roots of mushrooms. Altast Foods Co. is using solid state fermentation to grow mushroom tissue on mycelium scaffolds. They harvest this tissue and use it to create bacon analogs.
Nanomaterials Nanomaterials exhibit unique properties at the nanoscale. London-based Biomimetic Solutions is leveraging nanomaterials in order to create scaffolds. Cass Materials in Perth, Australia, is using a dietary fibre called Nata de Coco (derived from coconuts) to create nanocellulose sponges for their BNC scaffold. Nata de Coco is biocompatible, has high porosity, facilitates cell adhesion and is biodegradable.
Spinning Immersion Jet Spinning is a method of creating scaffolds by spinning polymers into fibres. It was developed by the Parker Group at Harvard. Their platform uses centrifugal force to extrude a polymer solution through an opening in a rotating reservoir. During extrusion, the solution forms a jet that elongates and aligns as it crosses the air gap. The jet is directed into a vortex-controlled precipitation bath that chemically cross links or precipitates polymer nanofibers. Adjusting air gap, rotation and the solution changes the diameter of the resulting fibres. This method can spin scaffolds out of PPTA, nylon, DNA and nanofiber sheets. A nanofibrous scaffold made from alginate and gelatin was able to support the growth of C2C12 cells. Rabbit and bovine aortic smooth muscle myoblasts were able to adhere to the gelatin fibres. They formed aggregates on shorter fibres, and aligned tissue on the longer ones. Matrix Meats is using electrospinning—a process that uses electric force to turn charged polymers into fibres for scaffolds. Their scaffolds allowed meat marbling, are compatible with multiple cell lines, and are scalable.
Additive manufacturing
Another proposed way of structuring muscle tissue is additive manufacturing. Such a technique was perfected for industrial applications in manufacturing objects made out of plastic, metal, glass and other synthetic materials. The most common variation of the process involves incrementally depositing a filament in layers onto a bed until the object is completed. This method will most likely lend itself best to the application of cultured meat as opposed to other types such as binder jetting, material jetting or stereolithography that require a specific kind of resin or powder. A filament of muscle cells can be printed into a structure meant to resemble a finished meat product which can then be further processed for cell maturation. This technique has been demonstrated in a collaboration between 3D bioprinting solutions and Aleph Farms that used additive manufacturing to structure turkey cells on the International Space Station. 3D bioprinting has been used to produce steak-like cultured meat, composed of three types of bovine cell fibers and with a structure of assembled of cell fibers that is similar to original meat.
Bioreactors
Scaffolds are placed inside bioreactors so that cell growth and specialization can occur. Bioreactors are large machines similar to brewery tanks which expose the cells to a large variety of environmental factors that are necessary to promote either proliferation or differentiation. The temperature of the bioreactor must replicate in vivo conditions. In the case of mammalian cells, this requires heating to 37 °C (99 °F). Alternatively, insect cells can be grown at room temperature. Most bioreactors are maintained at 5% carbon dioxide. Cells can be cultivated in either continuous or fed-batch systems. The former entails inoculating and harvesting cells in a constant process so that there are always cells in the bioreactor. Fed-batch systems mean inoculating the cells, culturing them and harvesting them in a single period. Stirred tank bioreactors are the most widely used configuration. An impeller increases the flow, thereby homogenizing the culture media and a diffuser facilitates the exchange of oxygen into the media. This system is generally used for suspended cultures but can be used for cells that require attachment to another surface if microcarriers are included. Fixed bed bioreactors are commonly used for adherent cultures. They feature strips of fibres that are packed together to form a bed to which cells can attach. Aerated culture media is circulated through the bed. In airlift bioreactors, the culture media is aerated into a gaseous form using air bubbles which are then scattered and dispersed amongst the cells. Perfusion bioreactors are common configurations for continuous cultivation. They continuously drain media saturated with lactic acid that is void of nutrients and fill it with replenished media.
Challenges
Growth factors The culture media is an essential component of in vitro cultivation. It is responsible for providing the macromolecules, nutrients and growth factors necessary for cell proliferation. Sourcing growth factors is one of the most challenging tasks of cellular agriculture. Traditionally, it involves the use of fetal bovine serum (FBS) which is a blood product extracted from fetal cows. Besides the argument that its production is unethical, it also violates the notion that the cultured meat is produced independent of the use of animals. It is also the most costly constituent of cultured meat, priced at around $1000 per litre. Furthermore, chemical composition varies greatly depending on the animal, so it cannot be uniformly quantified chemically. FBS is employed because it conveniently mimics the process of muscle development in vivo. The growth factors needed for tissue development are predominantly provided through an animal's bloodstream, and no other known fluid can single-handedly deliver all these components. The current alternative is to generate each growth factor individually using recombinant protein production. In this process, the genes coding for the specific factor are integrated into bacteria which are then fermented. Due to the added complexity of this process, it is particularly expensive. Future Fields, a Canadian company focused on overcoming the economic and environmental costs of traditional growth media, is developing serum-free growth factors from fruit flies. The ideal medium would be chemically quantifiable and accessible to ensure simplicity in production, cheap and not dependent on animals. It will most likely be derived from plants; and while this may reduce the possibility of transmitting infectious agents, it may induce allergic reactions in some consumers. Such culture sera may also require modifications specific to the cell line to which they are applied. Companies currently invested in developing effective plant based culture include Multus Media and Biftek. The Good Food Institute (GFI) put out a report in 2019 in support of the concept that cell-based meat could be produced at the same cost as ground beef and in 2021 they commissioned a report from CE Delft on the Techno-Economic Analysis of cultivated meat. Another proposed approach is to subject the cell lines to a magnetic field, which can stimulate the release of molecules that have regenerative, metabolic, anti-inflammatory and immunity-boosting properties, acting as an alternative to serum.
Surface area A common challenge to bioreactors and scaffolds is developing system configurations that enable all cells to gain exposure to culture media while simultaneously optimizing spatial requirements. In the cell proliferation phase, prior to the introduction of the scaffold, many cell types need to be attached to a surface to support growth. As such, cells must be grown in confluent