New Sources of Animal Proteins: Cultured Meat

TLDR: Cultured meat is a technology with the potential to solve major upcoming problems with food security and environment when meat demand will increase according to FAO expectations and the technology is available as shown by a proof of concept.

Abstract: Cultured meat is a technology with the potential—but not yet proven—ability to solve major upcoming problems with food security and environment when meat demand will increase according to FAO expectations. The technology is available as shown by a proof of concept. Turning cultured meat into a first commercial product available on the plate of consumers still requires different additional technical efforts to improve and complement the product, to scale-up production, to reproduce meat aging and to attain regulatory approval, and this will require time. These developments will be paralleled by replacing animal-derived materials by sustainable ones and by adding new components to the meat including fat tissue. Around the potential market introduction of the first product, consumer acceptance will be an important issue. If cultured meat enters the market, it will compete with conventional meat produced by more environmental friendly livestock practices, meat substitutes made from plant proteins, mycoproteins and insect proteins. Each type of meat substitute will have its own benefits and weaknesses. Apart from improved production of livestock meat, cultured meat is the only alternative that is based on muscle tissue from staple domesticated animals although muscle aging still needs to be investigated.

Figures

FIGURE 16.2 From proof of concept to a consumer product.

FIGURE 16.3 Main factors affecting meat consumption during the human history (A) and since the development of the economic world (B). In (B) only some examples of factors are given at the second level (white boxes). The main factors described in (B) can be extrapolated for all types of meat substitutes including cultured beef. (Part B, adapted from Font-I-Furnols, M., Guerrero, L., 2014. Consumer preference, behavior and perception about meat and meat products: an overview. Meat Sci. 98, 361–371.)

FIGURE 16.1 Process of culturing meat. 1, 2, Taking stem cells through a needle biopsy; 3, expanding number of cells through proliferation; 4, making tissues from myotubes that self-assemble around a central column so that they can attach to each other; 5, putting together a patty using standard food technology.

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New sources of animal proteins: cultured meat
Mark Post, Jean-François J.-F. Hocquette
To cite this version:
Mark Post, Jean-François J.-F. Hocquette. New sources of animal proteins: cultured meat. New
aspects of meat quality – from genes to ethics, Woodhead Publishing Limited, 2017, �10.1016/B978-
0-08-100593-4.00017-5�. �hal-01603257�

425
New Aspects of Meat Quality. http://dx.doi.org/10.1016/B978-0-08-100593-4.00017-5
Copyright © 2017 Elsevier Ltd. All rights reserved.
Chapter 16
New Sources of Animal Proteins:
Cultured Meat
M.J. Post* and J.-F. Hocquette**
,†
*Maastricht University, Maastricht, The Netherlands; **INRA, UMR1213 Herbivore, Saint Genès
Champanelle, France;
†
Clermont Université, VetAgro Sup, UMR1213 Herbivore, Saint Genès
Champanelle, France
1 INTRODUCTION
Mankind has been consuming meat perhaps for 1.5 million years and it has
greatly benefited us. Over time however, the cultural and nutritional necessi-
ties have changed and they will continue to change. The current balanced view
of the people in developed nations on meat consumption is that although the
vast majority of consumers eat meat, it comes at a high price. It is recognized
that livestock meat production puts pressure on crop output and comes with
an appreciable burden on the environment through greenhouse gas emission
(FAO, 2011) At the same time, societal acceptance of intensified livestock
breeding and herding with perceived deterioration of animal welfare is dwin-
dling. It is also questionable if we can increase livestock meat production with
the same livestock farming systems to match the projected 70% increase in
demand over the coming decades.
Against this background, several alternative protein sources as well as alter-
native meat production systems are being explored. Alternative protein sources
are of vegetable, grain, fungal, algal, or insect origin. The nutritional value and
the life cycle of these nonmeat proteins vary tremendously, but they have in
common that neither of them produces the same tissue that consumers recog-
nize as meat even if some efforts are continuously made to mimic the taste and
shape of meat. Success of these alternatives therefore depends on the extent
to which they can replace meat as a staple and highly appreciated part of the
diet. Culturing meat from skeletal muscle and fat tissue precursor cells aims to
reproduce a muscle tissue which may be transformed into meat through alterna-
tive, production methods that are potentially more resource efficient and envi-
ronmentally friendly according to some authors. However, such a disembodied

426 PART | II New Techniques for Measuring, Predicting and Producing
production method also faces the challenge of public acceptance, as it may not
be perceived as being natural, healthy, or safe. The context of the discussion in
this chapter is the production of a biomimetic, that is, meat that is the closest
possible match to livestock beef.
The uncertainties of the future of meat consumption and production and the
uncertainties linked with alternative protein sources dictate comprehensive mul-
tidisciplinary research and development in every possible solution to a problem
that is both tangible and serious.
In this chapter, we discuss alternative production methods of meat and cul-
turing beef in particular. The choice for beef is rational as this meat is least
efficiently produced through livestock and is also associated with the highest
green house gas emission per kilogram.
2 TECHNOLOGY
Techniques to culture tissue including skeletal muscle have quite recently been
developed in a new medical field called regenerative medicine. The goal of this
endeavor is to replace dysfunctional of dysmorphic tissue by newly cultured
and fully functional tissue from patient’s own cells. The originating cells may
be stem cells, typically adult stem cells that are tissue specific, or can be derived
from tissues that consist of cells that retain replicative capacity.
To grow de novo muscle tissue and perhaps other components of meat, such
as fat and connective tissue, three basic components are required:
1. tissue specific cells with replicative capacity,
2. a biomaterial that at least temporarily keeps cells in a tissue configuration,
and
3. a bioreactor to feed the tissue and to provide mechanical and biochemical
stimuli for optimal differentiation of the tissue culture.
The same conditions also apply to culturing meat for the purpose of con-
sumption.
Meat consists mostly of skeletal muscle cells and because mature skel-
etal muscle cells no longer proliferate, stem cells are the only possible source
of replication-competent precursors. Fortunately, after the discovery of myo-
blasts in skeletal muscle, it was proven that they are the bona fide muscle
stem cells in that they can self-renew and repair damaged muscle tissue (Seale
et al., 2000). Since then, it has been shown that this group of cells, identified
on the basis of Pax7 and CD56 positivity, is in fact a heterogeneous group
(Motohashi and Asakura, 2014). The practical implication of this heteroge-
neity is as yet unknown. By well-described and relatively simple methods,
myoblasts can be harvested from a fresh piece obtained by a transcutaneous
needle biopsy of a cow muscle (Fig. 16.1). By very finely mincing the tissue
and by brief and light enzymatic digestion, muscle cells with their myoblasts
attached are plated under standard culture conditions. After a couple of days,

New Sources of Animal Proteins: Cultured Meat Chapter | 16 427
the myoblasts migrate through the basal membrane of the muscle fiber and
will start to proliferate. Depending on the purity of the biopsy, 95% of the
eventual cell population consists of CD56 positive myoblasts. Myoblasts can
be replicated by standard cell culture methodology using serum-supplemented
medium as “feed.” Medium is a fluid that contains all necessary nutrients
and vitamins for cells to grow. Myoblasts have sufficient but limited replica-
tive capacity with a maximum of 45 doublings being reported in human cells
(Hughes et al., 2015).
As myoblasts depend on attachment to a surface for their survival and
growth, they are traditionally cultured in large numbers on the plastic bottom
of culture flasks.
Once a sufficient number of myoblasts are obtained, the cells can be used in
batches of 2 million cells to form a multicellular tissue in the form of a muscle
fiber, the basic building block of a muscle and therefore of meat. To this end,
the cells are submerged in a gel or scaffold that gives temporary support and al-
lows the cells to merge and to connect to each other. By providing anchor points
to the nascent tissue, the cells will align in between the anchor points and start
to build up tension. This tension is the result of contractile proteins, but at the
same time it is the strongest stimulus for the cells to express these proteins, thus
entering a virtuous cycle. After approximately 3 weeks the muscle fibers are
mature and can be harvested. They will be 2–3 cm long but less than 1 mm in
diameter when they are harvested. Subsequently, the fibers are assembled into a
patty to create a hamburger or any other presentation of minced meat. Standard
food technology, including salt, seasoning, breadcrumbs, egg white powder, and
a binder are used to make a firm patty that can be handled and cooked.
FIGURE 16.1 Process of culturing meat. 1, 2, Taking stem cells through a needle biopsy; 3, ex-
panding number of cells through proliferation; 4, making tissues from myotubes that self-assemble
around a central column so that they can attach to each other; 5, putting together a patty using
standard food technology.

428 PART | II New Techniques for Measuring, Predicting and Producing
The current technology has several disadvantages including limited scal-
ability, repetitive handling with associated risk of contamination, and last but
not least, inefficient use of resources, such as feedstock, disposable materials,
energy, water, and manpower.
3 TECHNICAL CONDITIONS FOR FEASIBILITY
To turn cultured beef as proof of concept into a consumer product (Fig. 16.2)
with the ambition to reduce resources, environmental and animal welfare im-
pact, several conditions need to be met. The product can no longer contain
animal materials other than the bovine myoblasts, cell production needs to be
scaled to industrial proportions, tissue production will be automated, regulatory
approval should be attained, and consumer acceptance has to be studied and
guided. For the cultured beef to solve the environmental issues, production has
to be resource and energy efficient.
3.1 Eliminating Animal-Derived Materials
Some of the currently used materials to make cultured beef are still animal
derived and therefore not sustainable. They need to be replaced by either plant-
based or synthetic biomaterials. In particular, fetal bovine serum (FBS) is tra-
ditionally used to culture cells. Ever since Burrows and Carrel were successful
in cultivating mammalian tissue using serum (Carrel and Burrows, 1911), it has
been a staple in cell culture. It is largely unknown which components of serum
FIGURE 16.2 From proof of concept to a consumer product.

Frequently asked questions

Q1. What are the contributions mentioned in the paper "New sources of animal proteins: cultured meat" ?

In this paper, the authors discuss alternative production methods of meat and culturing beef in particular, and the context of the discussion in this chapter is the production of a biomimetic, that is, meat that is the closest possible match to livestock beef. 

Q2. What have the authors stated for future works in "New sources of animal proteins: cultured meat" ?

In Vitro Meat Cookbook that was launched in 2014 suggest a wide range of new products from cultured meat, illustrating that their current concept of meat may be challenged in the future. Perhaps more interesting is the potential creation of healthier muscle products that contain for instance less fat or more polyunsaturated fatty acids, such as w-3 fatty acids, which reduce the risk of cardiovascular disease. 

Q3. What is the purpose of adding fat to adipose tissue?

To complement flavor, but also to add nutritional value and enhance the texture of meat, adipose tissue needs to be added to the product. 

Q4. What is the way to make a patty?

Standard food technology, including salt, seasoning, breadcrumbs, egg white powder, and a binder are used to make a firm patty that can be handled and cooked. 

Q5. What are the disadvantages of the current technology?

The current technology has several disadvantages including limited scalability, repetitive handling with associated risk of contamination, and last but not least, inefficient use of resources, such as feedstock, disposable materials, energy, water, and manpower. 

Q6. What is the common reason why meat is considered to be ethical?

according to one author, “artificial” meat will be considered to be ethical only if it is more effective at reducing conventional animal meat consumption than plant-based analogs (Laestadius, 2015). 

Q7. How many doublings of myoblasts have been reported in human cells?

Myoblasts have sufficient but limited replicative capacity with a maximum of 45 doublings being reported in human cells (Hughes et al., 2015). 

Q8. What are the only meat substitutes that are currently widely available to consumers?

Other authors observed that the only meat substitutes that are currently widely available to consumers are meat replacement products manufactured from plant proteins and mycoproteins. 

Q9. What is the reason for the muscle being tough?

More precisely, after slaughter of farm animals, muscle fibers go into rigor mortis due to protein contraction and the muscle is tough. 

Q10. What are the main reasons why the authors need to wait for the production of these models?

The uncertainties in these models are large and the authors therefore have to wait for scaled production and improvements in technology, so that these models can gain a higher level of predictability. 

Q11. What is the reason for the formation of small pieces of muscle?

The formation of small pieces of muscle, such as in hamburgers or other forms of processed meat relies on the innate tendency of muscle cells and fibers to self-assemble in the previously mentioned matrix or scaffold. 

Q12. Why have prehumans and humans been eating meat among other types of food?

Throughout evolution, prehumans and human beings have been eating meat among other types of food simply because humans are omnivores. 

Q13. What is the cost of growth medium for mammalian cells?

Growth medium for mammalian cells is expensive and theproduction is proportioned to the demand for scientific experiments and medical applications. 

Q14. What was the favorable resource saving?

The most favorable resource saving came out of one of the earliest studies, where the assumption was that algae products could be used to feed myoblasts in culture to produce beef. 

Q15. What are the main factors that affect the acceptance of any new food product?

the acceptance of any new food product (including cultured meat) will primarily depend on these three main factors: hygiene, safety, and an affordable price. 

Q16. What is the recent study that predicted a saving of energy?

That study resulted in a predicted saving of roughly 90% water and land usage and 60% energy (Tuomisto and Teixeira de Mattos, 2011). 

Q17. What is the recent study that predicts that culturing meat does not save energy?

more recent study, predicts that culturing meat does not save energy but may lead to increased energy expenditure while still preserving water and land supply (Mattick et al., 2015). 

Q18. How does the success of alternative protein sources depend on the extent of their replacement?

Success of these alternatives therefore depends on the extent to which they can replace meat as a staple and highly appreciated part of the diet. 

Q19. How many people think that artificial meat will be healthy and tasty?

Thirty to 45% of respondents did not think that “artificial meat” will be the solution to solve the aforementioned problems and 24–42% believe that artificial meat will be healthy and tasty.