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REVIEW ARTICLE
Plant-based and cell-based approaches to meat
production
Natalie R. Rubio1, Ning Xiang1& David L. Kaplan 1✉
Advances in farming technology and intensification of animal agriculture increase the cost-
efficiency and production volume of meat. Thus, in developed nations, meat is relatively
inexpensive and accessible. While beneficial for consumer satisfaction, intensive meat pro-
duction inflicts negative externalities on public health, the environment and animal welfare. In
response, groups within academia and industry are working to improve the sensory char-
acteristics of plant-based meat and pursuing nascent approaches through cellular agriculture
methodology (i.e., cell-based meat). Here we detail the benefits and challenges of plant-
based and cell-based meat alternatives with regard to production efficiency, product char-
acteristics and impact categories.
Global production and consumption of meat continue to surge as demand is driven
upward by population growth, individual economic gain, and urbanization1,2. In 2012,
the Food and Agriculture Organization (FAO) of the United Nations projected the global
demand for meat would reach 455 M metric tons by 2050 (a 76% increase from 2005)3. Likewise,
the global demand for fish is projected to reach 140 M metric tons by 20504. The majority of this
incline is attributed to middle-income countries (e.g., China), as consumption in higher-income
countries is relatively stagnant or marginally decreasing (e.g., United Kingdom) and in lower-
income countries, the rate of consumption is fairly constant (e.g., India)1. This pattern is con-
sistent with a proposed theory that the relationship between meat consumption and income
follows an “inverted U-shaped”trend; consumption initially increases with rises in income but
eventually reaches a turning point at which consumption stagnates or declines5. This observation
may be rationalized by correlations between high income and increased concern for the con-
sequences of animal agriculture5.
This rising demand is problematic as current methods of large-scale animal husbandry are
linked to public health complications, environmental degradation and animal welfare concerns.
With regard to human health, the animal agriculture industry is interconnected with foodborne
illness, diet-related disease, antibiotic resistance, and infectious disease6,7. Notably, zoonotic
diseases (e.g., Nipah virus, influenza A) are linked to agricultural intensification and meat-
packing plants in the United States were hotspots for COVID-19 outbreaks7,8. Animal agri-
culture also contributes to environmental issues including greenhouse gas emissions, land use,
and water use1. The United Nations Intergovernmental Panel on Climate Change released a 2018
report asserting that greenhouse gas emissions must be reduced 45% by 2030 to prevent global
temperatures from increasing 1.5 °C; a target that could mitigate catastrophes associated with a
2.0 °C increase9. Conventional mitigation techniques include improvements in reforestation, soil
conservation, waste management as well as tax policy, subsidies, and zoning regulations10. While
these strategies remain important, the urgency of climate change may require more
https://doi.org/10.1038/s41467-020-20061-y OPEN
1Department of Biomedical Engineering, Tufts University, 4 Colby St., Medford 02155 Massachusetts, USA. ✉email: david.kaplan@tufts.edu
NATURE COMMUNICATIONS | (2020) 11:6276 | https://doi.org/10.1038/s41467-020-20061-y | www.nature.com/naturecommunications 1
1234567890():,;
transformative approaches. Lastly, with regard to animal welfare
concerns, each year billions of animals are killed or suffer either
directly (e.g., farm animal slaughter, seafood fishing) or indirectly
(e.g., fishing by-catch, wildlife decline due to habitat destruction)
in relation to human food systems11,12.
The majority of the aforementioned issues can be attributed to
the fact that the raw material inputs (i.e., animals) for conven-
tional meat production are inherently unsanitary, inefficient, and
sentient. By removing animals from the manufacturing process,
several externalities may be alleviated. Plant-based meat (PBM)
and cell-based meat (CBM) approaches offer to generate food
from non-animal sources. While traditional PBMs (e.g., tofu)
have existed for centuries, novel PBM alternatives with enhanced
sensory characteristics have been commercialized more recently
(Fig. 1)13. Other groups have initiated the development of a new
field—cellular agriculture. Cellular agriculture describes the tactic
of producing commodities from cells, rather than whole organ-
isms or animals, such as CBM; meat grown from muscle or fat
cells rather than cows, pigs or chickens. While there is evidence to
support certain benefits of these approaches compared to animal-
based meat (ABM), it is important to more comprehensively
evaluate impacts on human health and the environment as pro-
duction systems evolve. In addition, widespread adoption of these
products will require more direct benefits to the consumer; such
as taste, cost, and convenience14. This review serves to compare
plant-based (i.e., meat analogs composed of plant proteins) and
cell-based (i.e., meat analogs generated from cell cultures)
methods to educate stakeholders about the strengths and chal-
lenges of each approach and highlight areas of uncertainty.
History and approach
Plant- and fungi-based meat (PBM) products encompass the
flavor, texture, and/or nutritional aspects of meat but are different
in composition; namely are made from non-animal sourced
materials. Based on the time of development and technical
complexity, PBM products can be differentiated into two flexible
categories: traditional and novel (i.e., next-generation)13. Tradi-
tional meat analogs were developed thousands of years ago in
Asia and include relatively simple derivatives from soybeans (i.e.,
tofu, tempeh) or wheat (i.e., seitan)13. In contrast, novel PBMs are
characterized by the design and marketing of products as near
equivalent replacements for ABM with regard to taste, texture,
and nutrition. Product categories can also exist between tradi-
tional and novel, as they may meet some but not all of the
aforementioned criteria. A distribution map of global companies
and brands developing novel PBMs can be found in Fig. 2.
Typically, the production of PBM includes three steps15: (i)
Protein isolation and functionalization—Target plant proteins are
extracted from plants, some of which are subjected to hydrolysis
in order to improve their functionalities such as solubility and
cross-linking capacity; (ii) Formulation—The plant proteins are
mixed with ingredients to develop meat texture such as food
adhesives, plant-based fat and flour. Nutrients are added to match
or exceed the nutrient profile of the meat. (iii) Processing—The
mixture of plant proteins and other ingredients undergo protein
reshaping processes (e.g., stretching, kneading, trimming, press-
ing, folding, extrusion, etc.) to form a meat-like texture. Inno-
vative technologies being utilized to improve the organoleptic
properties of PBMs include shear cell technology, mycelium
cultivation, 3D printing, and recombinant protein additives16,17.
CBM, also referred to as in vitro meat, lab-grown meat or
cultured meat, is meat produced by cultivating cells as opposed to
farming animals. CBM technology is based on advances in stem
cell biology (e.g., induced pluripotent stem cells) and tissue
engineering (e.g., in vitro skeletal muscle grafts) originally pur-
posed for medical applications. CBM production involves four
central components: (1) muscle and fat cell isolation and culture,
(2) xeno-free culture medium formulation, (3) scaffold develop-
ment, and (4) bioreactor design; the details of which are described
extensively elsewhere14. Interestingly, the concept of CBM can be
traced back to 1930 when Frederick Smith, the British Secretary
for India, envisioned the genesis of “self-reproducing steaks”
through an excerpt of his essay collection The World in 2030 AD,
which reads: “It will no longer be necessary to go to the extra-
vagant length of rearing a bullock in order to eat its steak. From
one ‘parent’steam of choice tenderness, it will be possible to grow
as large and as juicy a steak as can be desired18.”While CBM has
yet to be commercialized in 2020, noteworthy progress has taken
place over the past couple of decades. Key milestones include the
first CBM patent filed by Willem van Eelen in 199919, the first
peer-reviewed research on cultured fish funded by NASA in
200220 and the first cultured beef burger debuted by Maastricht
University in 2013. Today, there are dozens of start-up companies
around the globe working to bring CBM products to market.
Economics
Key sources of protein inputs for novel PBM are relatively
inexpensive. The majority of plant-based products are primarily
formulated with pea, soy or wheat protein. The agricultural prices
(received by farmers in the United States) for these key proteins
Time
period Hunter-gatherer
100,000 – 6000 BC
Animal-Based Meat
Plant-based meat
Cell-based meat
Domestication
of plants and
livestock
Development
of irrigation systems
Improvements of
farming equipment
First
documentation of
seitan production
First
documentation of
tofu production
First documentation
of yuba production
Development of
nuttose
Genesis of cell
culture technology
First
documentation of
the concept
Debut of the first
cell-based burger
Commercialization
of soy- and
wheat-based
analogs
Next-generation
product innovation
Utilization of
livestock land
enclosures
Selective breeding
of livestock
Agricultural
revolution
Administration
of antibiotics in
livestock
Expansion of factory
farming
Agricultural
6000 – 900 BC
Classical
900 BC – 600 AD
Medieval
600 – 1500 AD
Early Modern
1500 – 1800 AD
Late Modern
1800 – 1900 AD
Early Global
1900 – 1950 AD
Late Global
1950 AD – Present
Fig. 1. The history and evolution of animal-, plant- and cell-based approaches to meat production. 13,87–93. Humans have consumed plant-based meat
(2555 years ago) for only 0.098% of the time period for which their ancestors have consumed animal-based meat (2,600,000 years ago). Likewise,
humans have eaten cell-based meat (7 years ago) for only 0.274% of the time period for which they have consumed plant-based meat.
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are 3.8–12.7 times lower than prices received for cattle, hogs, and
broilers. In fact, sometimes soy and wheat are combined with
ABM to reduce costs for processed meat products21. When
standardized by cost (2009 data) per gram of protein, soybeans
($0.01/g) and wheat ($0.03) are still remarkably less costly than
cows ($0.32/g), pigs ($0.22/g), and chickens ($0.12/g)22. Despite
this glaring discrepancy on the key protein input level, novel
PBMs tend to cost more than their animal-based counterparts in
a retail setting. This discrepancy may be partially due to pro-
cessing costs as 94.3% of retail costs for crop products are asso-
ciated with post-harvest processes, while this accounts for ~50%
of the retail costs for beef22. Furthermore, aside from primary
proteins, PBMs often include plant-based fats, flavor enhancers,
and color additives which contribute to cost. Some consumers are
willing to pay premiums for meat substitutes linked to personal
health benefits23.
Economic feasibility is a significant hindrance to CBM com-
mercialization24. The cultured beef burger cultivated by Maas-
tricht University in 2013 is reported to have cost $280,400
($2,470,000/kg) to produce. The production process involved
three researchers using bench-scale techniques to culture 20,000
muscle fibers over three months and served as a proof-of-concept
rather than an attempt to scale production. A few groups have
performed preliminary economic analyses to project the cost of
CBM for large-scale production scenarios (Table 1). In 2008, The
In Vitro Meat Consortium estimated, by modeling capital and
growth medium costs based on data for single-cell protein pro-
duction, CBM could cost approximately twice as much as
chicken25. In 2014, a study speculating on the technical, societal,
and economic factors of village-scale CBM production calculated
a cost range of $11–520/kg dependent on the price of growth
medium24. Invertebrate (e.g., insect, crustacean) cell culture may
present a more cost-efficient platform for CBM production based
on the unique properties of insect cells (e.g., xeno-free growth
medium, high-density suspension culture)26,27. Select companies
are targeting high-value products (e.g., foie gras, bluefin tuna,
kangaroo meat) in order to lower the bar for reaching price
parity. Interesting, a recent consumer acceptance study from the
Netherlands reported 58% of participants were willing to pay a
37% premium for cell-based beef compared to conventional
animal-based beef28.
Regulatory framework
PBMs are regulated in a similar manner as other non-animal
foods. In the United States, the Food and Drug Administration
(FDA), and specifically the Center for Food Safety and Applied
Nutrition (CFSAN), oversees food inspection, labeling, packaging,
imports, and facility safety. Most PBM products contain simple
ingredients that have previously been approved for human con-
sumption. Novel ingredients may be subject to additional
Type
Cell-Based Meat
Plant-Based Meat
© 2020 Mapbox © OpenStreetMap
Fig. 2 Geographical distribution of plant-based (green circles) and cell-based (orange circles) meat companies. Companies were included as listed in
the Good Food Institute alternative protein company database (August 2020).
Table 1 Results from preliminary economic analyses of CBM production24,25.
Reference [Doyle et al.,25]a[van der Weele & Tramper24]b
Growth medium-cost range (USD/L) 10.29–11.76 1.33–66.50
CBM cost range (USD/kg) 4.81–5.10 10.39–519.53
CBM per volume growth medium (kg/MT) 193 128
aEstimates are based on capital, variable media, and overhead costs for a plant capacity of 15,000 tons/year. The lower limit is estimated for cells grown in suspension and the upper limit is estimated for
cells grown in a 3D matrix.
bEstimates are based on batch production of 2560 kg CBM per batch assuming 20,000L/batch. CBM cost only considers contributions from growth medium.
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evaluation processes. For example, soy leghemoglobin, produced
via genetic engineering, filed for “generally recognized as safe”
status with the FDA for use as a color additive17. In the European
Union (EU), current policy and regulation are supportive for
alternative proteins innovation and investment. In 2018, the
European Commission presented a “EU Protein Plan”, which
encourages the production of alternative proteins for human
consumption, and listed existing EU policy instruments that
“provide options for strengthening the development of EU-grown
plant proteins”. Many novel PBM products are classified under
the Novel Food Regulation which regulates “food that had not
been consumed or do not exist in the EU before 15 May 1997”23.
Australia, Canada, and New Zealand have also introduced legis-
lation to guide oversight of novel foods13. Government oversight
is also required for food labeling. In 2018, The United States
Cattlemen’s Association petitioned the Food Safety and Inspec-
tion Service (FSIS) “to exclude products not derived directly from
animals raised and slaughtered from the definition of “beef”and
“meat”29. The use of terms such as steak, sausage, bacon, fillet,
etc. for PBMs is subject to scrutiny and restriction in many EU
member states as well.
Oversight for CBM involves the regulation and monitoring of
production, packaging, labeling, and marketing. In the United
States, CBM will be jointly regulated by the FDA and the United
States Department of Agriculture (USDA) based on a decision
announced by the departments in 201930. The FDA will regulate
cell isolation, storage, growth, and maturation. After cells and
tissues have been harvested, the USDA will monitor products
through the remainder of the commercialization process and
oversee labeling30. Scaffold materials may fall under FDA food
additive provisions31. Even with a joint effort, it will be important
to utilize current systems but also to implement new regulation
procedures as the technology continues to advance32,33. Further
complication could arise if companies intend to sell products
containing genetically modified (GM) cells. While the USDA
regulates GM crops, a FDA New Animal Drugs Application
provision views DNA manipulation to fall under the definition of
a drug and dictates FDA oversight of GM animals; this could
potentially be interpreted to also apply to GM cells33. A second
concern about regulations is with respect to accurate labeling.
Similar to the PBM labeling debate, there is an effort to prevent
cell-based products from being labeled as “meat”29. Based on the
Federal Meat Inspection Act which refers to meat as “any pro-
duct…made wholly or in part from any meat or portion of the
carcass”, there may be justification for CBM to retain its wording.
In fact, the North American Meat Institute states that cell-based
products likely fall into the definitions of either “meat”or “meat
byproduct”34. For Europe, CBM could be applicable to the Eur-
opean Union Novel Food Regulation pathway. While the Food
Safety Authority has approved GM food production, contingent
on thorough safety assessments, many European countries (e.g.,
France, Germany, Greece) have banned the production and sale
of GM foods35.
Organoleptic properties
The chief organoleptic (i.e., sensory) properties of meat are
appearance, aroma, flavor (Table 2), and texture. Novel PBMs
mimic the look of ABM by manipulating color, fat marbling and
structure (Fig. 3). Depending on the product, PBMs aim to
emulate the appearance of raw (e.g., ground meat) or pre-cooked
meat (e.g., deli slices). Heat-stable fruit and vegetable extracts
(e.g., apple extract, beet juice) or recombinant heme proteins (e.g.,
LegH) are used to both recreate the color of fresh meat and
change to brown upon cooking17,36. To mimic the appearance of
fat, some novel PBM products exhibit visible semi-solid plant-
based fats (e.g., coconut oil, cocoa butter). Engineering flavor and
aroma profiles are important to recapitulate the taste and smell of
meat. In meat analogs, flavor additives are incorporated to add,
enhance or mask specificflavor notes and generally compose
3–10% of the product21. Many plant proteins are associated with
bitter and astringent tastes, which require selective compound
removal by post-processing15. In particular, soy products have
strong grassy, beany and bitter flavors linked to lipoxygenase,
saponin and isoflavone compounds which can be reduced
through germination or heating15. A synthetic meat flavor
developed in the 1980s was composed of sugar, amino acids,
nucleotides, glycoprotein, monosodium glutamate, salt, and fat
and determined by a sensory panel to be equal or superior to
meat extract37. Recombinant protein additives like LegH can
contribute to the flavor as well as the color of PBMs17. PBM
texture can be influenced by high-moisture extrusion, shear cell
technology, mycelium cultivation and 3D printing. Extrusion,
shear cell technology and 3D printing rely on applying
mechanical, thermal and shear stresses to a protein mixture to
obtain a semi-solid fibrous structure16. While many strategies are
available to engineer and tune the texture of plant proteins, it can
be difficult to balance processing methods to achieve desired
mechanical properties while also retaining nutritional value15.
Conversely, mycelium cultivation involves growing filamentous
fungi; particular strains of which emulate the microstructure of
meat38. Quorn™is a fungal-based PBM that has provided alter-
natives for chicken nuggets, meatballs, and minced meat since the
1960s38. New start-ups (e.g., AtLast Food Co., Emergy Foods) are
growing mycelia with goals of generating higher quality cuts of
meat, such as steak.
To increase the likelihood of mainstream consumer adoption,
CBM must be equivalent or superior to ABM from a sensory
perspective39. The 2013 cultured beef burger (which contained
cultured skeletal muscle tissue but not adipose tissue and was
flavored with beet juice, bread crumbs, caramel, egg powder, salt
and saffron) was described as tasting “like a real burger”by one
panelist and “close to meat, but not that juicy”by another40. Since
this milestone, more effort has been focused on generating cell-
based adipose (i.e., fat) tissue; given its significant contribution to
taste and texture. Advances in engineering fat tissue for use in
food have been reviewed in depth elsewhere41. Aside from ske-
letal muscle and adipose tissue, ABM also contains connective
Table 2 Precursors and compounds attributable to the aroma and flavor of meat.
Flavor precursor
categories82
Specific examples83,84 Thermal
reaction82
Flavoring compounds84–86 Associated
flavor84–86
Sugars nucleotides
Amino Acids Peptides
Glucose 5′-Adenosine
Monophosphate Cysteine
Anserine
Maillard
Reaction
Pyrazines, Alkylpyrazines, Alkylpyridines, Acylpyridines,
Pyrroles, Furans, Furanones, Pyranones, Oxazoles,
Thiophenes
Roasted,
Caramel, Meaty
Lipids fatty acids Phospholipids Linoleic acid Oxidation Hydrocarbons, Alcohols, Aldehydes, Ketones, 2-Alkylfurans Fatty,
Buttery, Sweet
Vitamins Thiamine Degradation Thiols, Aliphatic Sulfur Compounds, Furans, Thiophenes Ethereal, Heated
Onion, Sulfury
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tissue, vasculature networks, and supporting cell types (e.g.,
fibroblasts). The discrepancies in complexity may result in
nuanced flavor differences between ABM and CBM. CBM experts
indicate that key flavor profiles can be achieved by co-cultures,
medium supplementation, and/or genetic modification14,39. For
instance, researchers have explored the effects of supplementing
CBM with extracellular heme proteins (e.g., myoglobin)42.
Myoglobin is associated with the “bloody”flavor of meat and
supplementation was observed to improve the color of CBM
constructs without impeding muscle cell growth rates42. Early
cell-based prototypes emulate processed meat (e.g., burgers,
sausages, nuggets) as it is more difficult to emulate the appearance
and texture of whole cuts of meat (e.g., steak). As researchers in
the field begin to focus on textural properties, significant effort
will be required to evaluate myriad factors (e.g., cell to scaffold
ratio, the impact of cooking, packaging, storage, and shipping) on
tissue structure. CBM texture can be influenced both by cultured
cells and supportive scaffolding materials. In vitro skeletal muscle
tissue can be engineered to emulate the structure of meat by
employing differentiation and cell alignment strategies. For
example, mechanical tension, electrical stimulation, and/or
micropatterned substrates can be employed to induce cell align-
ment in vitro43. A recent study focused on CBM composed of
bovine cells coupled with a textured soy protein scaffold; finding
some of the samples exhibited texture (i.e., ultimate tensile
strength) properties similar to those of native bovine muscle44.In
addition, a sensory panel tasted the CBM samples and described
“a pleasant meaty flavor”and “a typical meat bite and texture”44.
Nutrition
The key plant-based proteins utilized in PBM formulations (e.g.,
pea, soy, wheat) provide total protein content at levels on par with
ABM. However, in order to ensure a balanced amino acid profile,
complementation of multiple plant-based proteins is generally
necessary. For instance, legume (low in sulfur-containing amino
acids, high in lysine) and cereal (low in lysine, high in sulfur-
containing amino acids) proteins are favorable complements.
Factors that have been identified in plant proteins that may decrease
nutrient bioavailability post-ingestion include: structures resistant to
proteolysis, protein conformation, and antinutrients (e.g., tannins,
phytates, lectins)45. Certain processing techniques (e.g., soaking,
heating, sprouting) have been shown to increase digestibility15.
Nutrition is also variable between traditional and novel PBM pro-
ducts. For example, tofu (traditional PBM) and Impossible™(novel
PBM) share certain benefits over ABMs such as containing dietary
fiber and minerals while lacking cholesterol. However, tofu-specific
benefits include fewer calories, less fat and sodium-free and
Impossible™-specificbenefits include higher protein and vitamin B
12
content (Fig. 4). Concern has been expressed regarding the inclu-
sion of LegH in PBM, citing correlations between heme iron intake
and increased risk of diabetes46.
Comprehensive, baseline nutrition data for CBM is not pub-
licly available. Using small sample sizes, the nutrient content of
cell cultures can be quantified via laboratory assays27. Different
cell types contribute different sets of nutrients; differentiated
muscle cells will likely be the primary source of protein and
mature adipocytes can contribute to the fatty acid profile41.
Certain compounds that are provided by ABM are not present in
cultured cells. For example, vitamin B
12
is only synthesized by
bacteria and will need to be supplemented47. As with flavor,
proponents of CBM often claim its nutrition profile will be
comparable with or superior to ABM and that nutrients can be
tuned via co-cultures, media supplementation, and genetic
modification14. Media formulation will have a large impact on the
viability and efficiency of the cultured cells, on the nutrition
profile, and perhaps also impact flavor and taste. Genetic mod-
ification for nutritional improvement is another approach that
may be more efficient in the long-term, although genetic
approaches may pose problems for regulatory strategy and con-
sumer acceptance. Genetic engineering has already been imple-
mented in livestock to improve various aspects of meat
production. In 2004, transgenic swine were generated to express a
gene originating in spinach with a goal of improving the fatty acid
profile of pork48. This and other modifications could be imple-
mented on a cellular level to influence the properties of CBM.
Comprehensive nutrition data for CBM should become available
with the launch of initial products, scale-up, and additional
interest from the scientific community.
Consumer acceptance
Consumer acceptance is of particular interest to PBM stake-
holders who are looking to increase market share. A high con-
sumer acceptance for PBM products was recorded in China
(95.6%) and India (94.5%), compared to the United States
(74.7%)49. In a European study, the main barriers for dietary
inclusion of PBMs were lack of familiarity and low “sensory
attractiveness”, and consumers who were unfamiliar with analog
products were more likely to want these products to closely
imitate ABM50. In a focus group study, motivating factors for not
eating ABM ranked differently in Germany (e.g., animal welfare,
health, environmental impacts), the Netherlands (e.g., animal
welfare, poor meat quality, health), and France (e.g., health,
animal welfare, sustainability)51. For all three nations, the taste
was the key factor inhibiting consumption of plant proteins, with
other factors including habit, convenience and price. In a sensory
panel study comparing animal-, plant- and insect-based burgers,
animal burgers were associated with the emotional terms of
‘contented, happy and pleasant’, while plant burgers were asso-
ciated with ‘disappointed, distrust and discontented’52. Beyond
and Impossible™products introduce a new class of PBM products
that more closely mimic ABM compared to the previously
established texturized vegetable protein items. These products
Plant-based meat Cell-based meat
Fig. 3 Plant-based and cell-based strategies for emulating appearance
properties (color, marbling, structure) of meat. Structure and marbling
are significant contributors to the texture of meat as well as appearance.
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may be viewed as “highly processed”compared to traditional
vegetable burgers and may alienate “clean label”consumers; who
are concerned about “unnatural”methods of food production53.
New consumer acceptance research is required to determine how
these products measure up to the findings reported for more
established products.
A general consensus in the field is that CBM is targeted at
consumers who currently eat meat; as plant-based diets are
agreed upon as healthful and sustainable for vegetarian-leaning
individuals. Interestingly, vegetarians and vegans in the United
States are both more likely to agree with the potential benefits of
CBM but less willing to try it compared to omnivores54. A sys-
tematic review of cultured meat consumer acceptance studies
found the most commonly reported concerns were associated
with: unnaturalness, safety, healthiness, taste, texture, and price55.
A 2017 European consumer study found that lack of naturalness
decreased acceptance of cultured meat; even with awareness of
potential environmental and animal welfare benefits56. Along
with this finding, research examining internet comments on
United States-based news articles covering cultured meat devel-
opment found more critical input than approval responses, and a
frequent critique was that CBM would be “unnatural”and
“unappealing”57. A 2018 Switzerland study concluded that
informing consumers about the production process did not
increase acceptance and that communications that emphasize the
final product, rather than the technical processes, would be a
more successful strategy58. Similarly, a 2020 Netherlands study
reported that educating consumers on the personal and societal
benefits had a positive impact on consumer acceptance28.
Nomenclature of meat grown from cell cultures may also have an
effect on consumer perspective. When comparing the effects of
‘animal-free, clean, cultured’and ‘lab-grown’on a panel of par-
ticipants, ‘animal-free’and ‘clean’incited more positive attitudes
compared to ‘lab-grown’59. Other common descriptors include
‘artificial’,‘cell-based’,‘cultivated’,‘in vitro’, and ‘synthetic’.
Public health
Meat is an important source of nutrition, especially in developing
countries facing nutrition deficiencies. However, the over-
consumption of meat has been linked to a number of health
concerns. More than 1.8 million people die each year from
ischemic heart disease, a quarter of which is linked with over-
consumption of certain meat products60. Results from a recent
clinical trial administered by the Stanford School of Medicine
demonstrated that participants who substituted PBM for ABM
over eight weeks exhibited lower risk for cardiovascular disease
(e.g., reduced fasting serum trimethylamine-N-oxide levels)61. The
consumption of PBM follows most nutritional dietary guidelines
which recommend to limit intake of red and processed meat62,63,
and could benefit consumers that desire reductions in blood
pressure, body mass index, and cholesterol64. Foodborne patho-
gens found in meat, such as Escherichia coli, Salmonella, and
Campylobacter, result in millions of illnesses each year65. Though
PBMs are generally not associated with pathogenic disease con-
cerns, non-animal products are capable of causing foodborne ill-
ness. A 1999 study screening tofu sold at grocery stores
determined that 16% of tested samples were contaminated with
coliform bacteria66. Plant foods can become contaminated with
pathogens via contact with contaminated sources of animal
manure, water or other foods. Antibiotics are also used in plant
agriculture, but at relatively low levels (in the United States, plant
use accounts for only 0.12% of animal agriculture antibiotic use)67,
therefore, compared with ABM, PBM is less associated with
antibiotic-related “drug-resistance”issue.
The commercialization of CBM could impact numerous
aspects of public health including foodborne illness, nutrition
deficiency, diet-related disease (e.g., colorectal cancer, cardiovas-
cular disease), and infectious disease6. The risk of foodborne ill-
ness from CBM could be theoretically non-existent, since the
sterile conditions required for cell proliferation will prevent
contamination with disease-causing pathogens, provided that
120% Beef
Pork
Chicken
Tofu
Impossible Beef
Quorn
100%
80%
60%
Percent of recommended daily intake
40%
20%
0%
Calories
Protein
Total fat
Saturated fatty acids
Total carbohydrates
Sugars
Dietary fiber
Vitamin B12
Sodium
Cholesterol
Iron
Zinc
Fig. 4 Nutritional value of ABM (beef, pork, and chicken), traditional PBM (tofu), novel PBM (Impossible™Beef), and mycoprotein (Quorn™) per
100 g wet weight, raw. Nutritional data for ABM and tofu were obtained from the FoodData Central database (FDC ID: 174036, 167902, 171116, 388713)
and Impossible™and Quorn™data were obtained from company websites. Content is quantified by the percent of recommended daily intake as
determined by the FDA94.
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6NATURE COMMUNICATIONS | (2020) 11:6276 | https://doi.org/10.1038/s41467-020-20061-y | www.nature.com/naturecommunications
post-processing and packaging procedures are equally sterile.
While sterile cell culture is implemented in pharmaceutical
manufacturing, it may not be economically feasible for food
production. Natural, food-grade antimicrobial agents may be a
promising strategy to reduce contamination risk while remaining
cost-effective68. Similarly, the threat of zoonotic disease trans-
mission could be directly reduced by decreasing human contact
with infected animals and indirectly by reducing habitat
destruction69. Nutrition deficiency and diet-related disease could
be addressed with cell selection, genetic modification, and med-
ium formulation strategies to regulate the presence of healthful
and unhealthful compounds. Conversely, consumers report
concerns with the safety and healthfulness of CBM, citing fears
about unnaturalness, cancer, and inadequate regulation55. So far,
public health claims on both sides are entirely speculative as the
relevant research has yet to be published.
Environmental sustainability
Beyond Meat®and Impossible™Foods have both released life
cycle assessments (LCA) for their plant-based beef products70,71.
Eutrophication potential and land use requirements for these
products are projected to be significantly lower than metrics
reported for factory-farmed animal-based beef, pork and chicken
while greenhouse gas emissions fall between metrics for pork and
chicken and energy consumption exceeds that of pork and
chicken (Fig. 5). Compared to estimates for Beyond and Impos-
sible™, mycoprotein (i.e., Quorn™) is more impactful with regard
to energy and emissions but requires less land for production
(Fig. 5). The water footprint of PBMs is highly dependent on the
source of the main protein. A LCA comparing meat alternatives
calculated that mycoprotein-based products (40 kg/kg) have
higher water requirements compared to gluten (0.954 kg/kg) and
soy-based (0.73 kg/kg) items72. A separate LCA study estimated
the water usage for 39 distinct meat analogs and determined that,
on average, a ton of PBM product consumed 3800 m3of water73.
A majority of the consumption is due to the processing of meat
analogs after harvest of the raw protein sources (transportation
and packaging were other factors).
The production of CBM is anticipated to, once optimized,
require fewer resources and emit less waste relative to ABM14.
Anticipated reductions are based on assumptions of: (1) targeted
tissue cultivation (i.e., reduced by-products, non-meat tissues);
(2) higher production rates and (3) vertical production systems14.
The first relevant LCA published in 2011 estimated CBM would
involve lower energy consumption (7–45%), greenhouse gas
emissions (78–96%), land use (99%), and water use (82–96%)
compared to ABM74. A separate 2015 LCA of CBM reported less
dramatic footprint reductions and determined that the energy
consumption, acidification potential, and ozone depletion
potential impacts of CBM could be more detrimental than ABM,
especially when compared to poultry production75. CBM is esti-
mated to have a 47% energy feed conversion efficiency and 72%
protein feed conversion efficiency, values that are lower than
PBM and insect-based meat but higher than ABM76.
Animal welfare
PBM products are generally free of animal byproducts and thus
do not have direct negative impacts on animal welfare. However,
a subset of products contains dairy-based or egg-based additives
and thus are vegetarian but not vegan. Similar to the meat
industry, egg, and dairy production methods are major sources of
animal welfare concerns. In the egg industry, millions of male
chicks that are not suitable for egg production or meat produc-
tion, are killed each year and the beaks of female birds are
trimmed to prevent pecking77. In the dairy industry, dairy cows
are repeatedly impregnated for continuous milk production and
are routinely separated from their calves, which are transported to
other farms for veal production; causing extreme emotional dis-
tress78. Even vegan PBM can have indirect effects on wild animal
welfare in the form of habitat destruction. To meet food demands,
Energy consumption
Greenhouse gas emission
Eutrophication
Land use
0.060
0
Beef Pork Chicken Plant-based meat Mycoprotein Cell-based meat
0.2 0.4 0.6 0.8 1 1.2 1.4
0.009
0.027
0.103
0.172
1
1
1
1
1.349
0.977
0.684
0.338
0.204
0.037
0.006
0.030
0.122
0.246
0.202
0.115
0.075
0.134
Fig. 5 Comparison of the environmental impact of meat and meat analogs. Data are normalized to the impact of beef production. Eutrophication does not
include data for mycoprotein. Land, emissions and energy data for mycoprotein were adapted from a 2015 LCA72. Data for beef, pork, chicken and CBM
were adapted from a 2015 life cycle assessment75. Data for PBM were adapted from an Impossible™Beef LCA (land, eutrophication, emissions) and a
Beyond Meat®life cycle assessment (energy use)70,71.
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NATURE COMMUNICATIONS | (2020) 11:6276 | https://doi.org/10.1038/s41467-020-20061-y | www.nature.com/naturecommunications 7
natural vegetation is cleared with monocultural crops which
impacts biodiversity. In 1994, palm oil cultivation in Malaysia was
found responsible for decreasing mammal inhabitants from 75 to
10 species per hectare79. While all agribusiness has an impact on
animal welfare that are worthy of concern, substitution of ABM
with PBM is still a substantial improvement for animal welfare, as
it avoids the unethical treatment of animals during rearing,
transportation and slaughter80.
One of the primary proposed benefits of CBM is the
improvement of farm animal welfare via supplanting intensive
animal agriculture. Animal donors are used to supply initial
sources of cells that are subsequently expanded in vitro, without
needing further resources from the animal. Donor animals,
usually younger animals that have more proliferative cells, are
anesthetized by a veterinarian and a small (<1 g) tissue biopsy is
removed. Cells could be genetically immortalized to proliferate
indefinitely; eradicating the need for animal donors. However, in
practice, animal donors will likely be relied upon to maintain
genetic diversity and to supply non-genetically modified options
for CBM. Aside from cell sourcing, a key aspect of CBM pro-
duction that is linked to animals is serum supplementation. Fetal
bovine serum is a common additive to cell culture media and it
provides essential growth factors for mammalian cell culture. In
2003, it was estimated that blood from 1,000,000 bovine fetuses
was harvested to generate the annual production of 500,000 liters
of fetal bovine serum81. Serum-free alternatives include co-
culture approaches or supplementation with recombinant growth
factors.
Looking forward
Animal-based meat production has evolved over thousands of
years to supply the demand for affordable and appetizing food.
Unfortunately, this feat is accompanied with unintended con-
sequences for human health, natural resources, and the animals
involved. Driven by both the rise in global meat demand and
increased concern about the aforementioned negative external-
ities, researchers, and entrepreneurs are turning their focus
towards animal-free approaches of meat production (Box 1). The
economic opportunity for meat alternatives is large and there is
no need to crown a single front-runner technology to monopolize
the market. Instead, it is important to pursue multiple solutions
simultaneously to provide a range of products to serve disparate
segments of the consumer market. Plant-based and cell-based
Box 1.
|
A summary of key comparisons between animal-based, plant and fungi-based and cell-based approaches to meat
production
History & Approach Meat consumption has been commonplace since the beginning of human evolution, while plant-based meat analogs are relatively
recent dietary additions. Cell-based meat products have not been commercialized, but people have taste-tested prototypes produced by companies and
via a singular academic study. Approaches to meat production can be primarily differentiated by starting material: animals (ABM), plants or fungi
(PBM) or cells (CBM).
Economics Advances in farming technology and intensification of animal agriculture have resulted in inexpensive and accessible ABM. Although raw
inputs for PBM (i.e., unprocessed plant proteins) are less costly than for ABM (i.e., livestock), PBM retail prices are consistently higher due to costs
associated with post-processing, production scale and supply chains. Current CBM production is not commercially feasible. Increases in production
scale and culture medium-cost reductions are necessary to improve the economics of the process.
Regulatory framework Regulation of novel foods such as certain PBM products and all CBM products is a current topic of interest. Namely, there is a
lack of precedent for oversight of food containing cultured cells. Novel additives for PBM may fall within existing regulatory frameworks (e.g., Novel
Food Regulation (Europe), “Generally Recognized as Safe”(United States) pathways). There are ongoing debates surrounding labeling laws of what
products can be characterized as meat.
Organoleptic properties The primary sensory properties of meat are appearance, aroma, flavor, and texture. Next-generation PBM products are
increasingly successful at mimicking processed ABM products (e.g., burgers, deli meat). Current strategies for producing structured PBM products (e.g.,
filets, steaks) include extrusion, shear cell technology, 3D printing, and mycelium cultivation. Early CBM prototypes appear to emulate ABM but few
people have been able to taste-test these samples. The first published sensory panel feedback of a CBM prototype (i.e., cow cells on a texturized soy
protein scaffold) reported “a pleasant meaty flavor”and “a typical meat bite and texture”.
Nutrition ABM is a good source of essential amino acids, minerals and vitamins. Some nutritional benefits of traditional PBMs include an absence of
cholesterol while providing sources of dietary fiber and healthy fatty acids. Improvements in organoleptic properties may come at the cost of certain
nutritional aspects. For example, notable novel PBM products contain high sodium content. There are no publicly available datasets regarding the
nutritional profile of CBM. Proponents of the technology assert that nutrition can be regulated by adjusting culture medium formulations and
implementing co-culture strategies or genetic modifications.
Consumer acceptance The motivations behind consumption of PBM vary depending on consumer nationality and China and India report higher
consumer acceptance rates of PBM compared to the United States. Next-generation PBM products can be perceived as “highly processed”and may not
be appealing to “clean label”consumers. With regard to CBM, plant-based consumers are more likely to agree with CBM’s proposed benefits but are
less willing to try it compared to omnivores. Consumer perception of CBM is influenced by marketing focus (e.g., process vs. product vs. impact) and
terminology (e.g., lab-grown vs. clean vs. cultured).
Public health Overconsumption of red and processed meat is linked to a number of health concerns. There is some evidence that substituting PBM
analogs for ABM products can decrease risk factors associated with cardiovascular disease. Compared to ABM, the production of PBM is less
associated with pathogenic disease and antibiotic resistance issues. The impact of CBM on public health issues depends on how large-scale production
schemes evolve (e.g., sterile processes, antibiotic use). Some consumers report concerns about the safety of CBM products, citing apprehension about
unnaturalness and inadequate regulations.
Environmental sustainability Life cycle analyses conclude PBM products are generally more environmentally sustainable than animal-based beef. Some
metrics (e.g., greenhouse gas emissions, energy consumption) for some novel PBM products are less sustainable when compared to animal-based
poultry. PBM water footprints vary widely depending on the main protein source. The environmental impact of CBM is highly debated, with preliminary
assessments presenting significant degrees of uncertainty; especially for energy consumption values.
Animal Welfare Billions of animals suffer and die each year as a direct result of ABM production. Vegan PBM products do not have as direct impacts on
animal welfare but crop cultivation can contribute to the destruction of wildlife habitats. One of the primary proposed benefits of CBM is the
improvement of farm animal welfare. However, CBM production currently utilizes donor animals for cell acquisition and the culture medium is
composed of animal-derived components. The creation of immortalized cell lines and animal-free culture medium ingredients are proposed to address
these issues.
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meat technologies have made significant advances since their
conception. PBM has evolved from being a lackluster meat
alternative, that provides a nutritional but not sensory replace-
ment to meat, to be a novel analog nearly indistinguishable from
the ABM it seeks to emulate. Likewise, CBM has matured from
being the musing of science fiction to being a tangible prototype.
PBM products lie on a spectrum where one end houses more
“natural,”less-processed proteins that fall in line with “clean-
label”viewpoints but do not do well to mirror the experience of
eating meat, while the other contains sensory equivalents that
require source proteins to be entirely transformed, and thus
viewed as highly processed, and which may come at the cost of
certain nutritional factors. Mycelium-based meat may be an
exception, where biofermentation can be employed to utilize
natural structures and growth patterns of filamentous fungi to
mimic meat structures. Along these lines, screening new protein
sources that exist in nature that may emulate meat without
excessive human manipulation may be an approach that appeals
to a wider pool of consumers. CBM is impeded by high pro-
duction costs, scale-up hurdles, and gaps in fundamental
knowledge surrounding how to employ cell culture for food
applications. In particular, there are no peer-reviewed, compre-
hensive datasets detailing the cost, sensory properties, or nutri-
tional value of cell-cultured tissues. While published assessments
of environmental impact projections exist, they are based on
theoretical large-scale processes that have yet to be validated by
industry. To that point, it will be necessary to ascertain details,
such as the parameters of material inputs (e.g., doubling time,
maximum cell density, medium composition) and industrial-scale
production schematics (e.g., bioreactor design, operations) before
cost, impact and food safety can be reliably analyzed.
There are opportunities for plant-based and cell-based hybrid
products. Considering the current high-cost hurdles associated
with CBM, one approach is to focus on the aspects of PBM that
fall short of ABM and determine where CBM can add the most
value at the lowest inclusion rate. For example, combining PBM
with cell-cultured fat may improve the sensory properties of the
analog while remaining less costly than a pure CBM product. To
this end, expanding research goals to answer fundamental ques-
tions surrounding the cost, sensory and nutrition profiles is
important to further inform stakeholders on the best areas of
application for CBM. Finally, eventual success of PBM and CBM
in the marketplace could transform, rather than eliminate, ABM
production. If demand for lower quality, previously factory-
farmed meat can be supplied with PBM and CBM, demand for
higher quality, ABM could be met by smaller-scale, more sus-
tainable and more humane methods of animal farming.
Received: 4 August 2020; Accepted: 6 November 2020;
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Acknowledgements
We thank our lab team members (Andrew, Kyle, John) for stimulating and productive
discussions. We thank New Harvest, the Good Food Institute, the Advanced Research
Projects Agency, and the National Institutes of Health (P41EB027062) for support.
Author contributions
D.K. and N.R. envisioned the topic and scope of the review. N.R. took the lead in writing
the manuscript and figure construction. N.X. aided in writing review sections concerning
plant-based meat and participated in figure construction. D.K. and N.X. provided input
on all sections of the review.
Competing interests
The authors declare no competing interests.
Additional information
Correspondence and requests for materials should be addressed to D.L.K.
Peer review information Nature Communications thanks the anonymous reviewer(s) for
their contribution to the peer review of this work.
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