Meat from a test tube
Текст: Tatiana Petukhova | 2018-10-31 | Фото: | 14831
Scientists have been struggling with the problem of how to provide enough food for the constantly growing population of our planet for a very long time. One of the possible solutions to it is culturing meat, i.e. producing it by growing it in special laboratory bioreactors instead of traditional animal farming. We have discussed the possibilities and prospects of this approach with Professor of Vascular Physiology at Maastricht University, developer of the technology of culturing meat out of animals’ stem cells Mark Post.

– Mark, the idea of growing meat in a laboratory is quite clear and, undoubtedly, very interesting from a scientific point of view. But what are its practical prospects? Is the humanity ready to implement such ideas right now or is it the question of a distant future? What do you think?

There are a lot of serious problems in the modern meat industry, and soon we are going to face a few more. According to the UN Food and Agriculture Organization, the demand for meat is going to grow by over 60% within the next 40 years. This is related not only to the growth of the world’s population – there are 7 billion of us now, and by 2050 it’s going to be 9 billion – but also to the increase of the gross domestic product in developing countries (India, China, Brazil, the countries of Africa) and the growth of the middle class in these countries. So, considering the fact that today animal farming is already using 70% of all the arable lands in the world, it becomes clear that very soon we simply won’t have enough place on the Earth for rearing cattle. Besides, animal farming as a means of meat production is very inefficient. Imagine a Quarter Pounder hamburger, which is called that because it contains a quarter of a pound of beef (a little over 100 grams). If you do your maths, you will find out that the production of this amount of meat requires about 50 gallons (227.3 liters) of fresh water, 7 pounds (3.17 kg) of grain, 70 square feet (6.5 sq. m) of land and 1000 BTU. This is a huge amount of resources.

But as serious as the problem of producing an ample amount of food is, it’s not the only problem. It is known that all grazing animals emit a large amount of methane and carbon dioxide into the atmosphere. And the methane is emitted by these animals not as much in the form of intestinal gases, as many people believe, as in the form of eructation. And this is a harmful gas that may cause what’s known as the greenhouse effect. As such, methane is 20 times as powerful as carbon dioxide, and we know that 40% of all methane emission into the atmosphere comes from livestock. In general, beef farming is responsible for 18% of all the greenhouse gas emissions, which is more than the emissions coming from the transport industry. Therefore a vegetarian driving a jeep would be less harmful for the environment than a meat-eater riding a bicycle.

And the third, but no less significant, problem is animal welfare. Everyone knows about it, even though a lot of people prefer not to talk about it or even not to think about it.

All these serious issues urge us to look for alternative ways of meat production. Of course, we can all become vegetarians, because humans can actually live perfectly well without animal protein. And by the way, we already have about 2 billion vegetarians on our planet, although the larger part of them gave up meat consumption involuntarily. However, there is one strong argument in favor of meat-eating: we really like it. I eat meat, too, and it’s in my own interests to create a high-quality product that will not be any different from natural meat.

In 1932, in his book ‘Thoughts and Adventures’, Winston Churchill asked himself the following question: «Why do we grow a whole chicken, when we only eat its breast and wings?» But what could he know about biology, he was a statesman. However, right at that time his physiologist friend and Nobel Prize winner Alexis Carrel made a breakthrough in science by discovering a way of sustaining life in organs separated from the body. He couldn’t create organs, but he learned to keep them alive when they are outside the body. At this point in history scientists conceived the basic idea of artificially growing body organs. During Churchill’s and Carrel’s time it was yet impossible, but today, thanks to the development of medicine, we have the stem cells technology and we have the explant culture technology, so the task becomes solvable.

© AnnieSpratt / pixabay

© markusspiske / pixabay

– Whenever possible, most people try to eat only natural products and are usually less than enthusiastic about artificially created replacements. Is the meat that you have learned to culture essentially artificial, or is it natural in the same way as common meat that we’re used to?

If you take a biopsy from a cow, get a small piece of muscle tissue and examine it with a microscope, then you’ll see muscle fibers as well as some quantity of fat cells that are important to develop the meat’s palatability. If you zoom in even more and look at this tissue sample then, you’ll see that the skeletal muscles consist of tiny muscle cells and even tinier stem cells. Muscle stem cells, like any stem cells, are capable of reproducing muscle tissue by means of cell division. Most of the time these cells are idle, but they start the process of muscle recovery whenever the muscle is damaged. These cells are like backup players in a sports game, that sit on the bench and wait when their team needs fresh energy. Like all stem cells, they can reproduce in large quantities: theoretically, having only one stem cell, one can culture up to 10,000 kg of meat. But muscle stem cells can also merge. The fact is that muscle fiber is a single structure with multiple cell nuclei. The merging of cells basically happens of its own accord — all we need to do is deprive these cells of nutrition. Then the cells stop reproducing and start merging into fibers. And they can do this not only inside the body but also outside it.

So, what do we do here? We take some muscle stem cells of a cow via a biopsy, put them into a Petri dish and let them attach themselves to something in it — we give them «attachment points» that they start to cling to. For this purpose we usually use a common adhesive tape which can be purchased in any supermarket. The cells are literally driven by the desire to «exercise», we don’t need to make them do it, they cling to these «attachment points» on their own and start creating tension and forming small muscle fibers. 20 thousand of such fibers (which makes for about 60 billion cells) are enough to make one hamburger patty. And if you look at these cells through a microscope, you will not see any difference between them and the real ones.

Naturally, we have to feed the cells, too: provide sugars and amino acids, vitamins, minerals, fats. Modifying nutrition also allows us to change the cells’ biochemistry to make them produce more polyunsaturated fatty acids and thus increase the meat’s nutritional value. We know that cells are capable of that, because the meat of animals that graze on pastures contains more of such acids than the meat of animals that never leave their stalls. These capabilities of biochemical regulation can be easily made use of in a laboratory, because there we can have full control over how much of proteins and amino acids the cells get.

© Mosa Meat 

Myosatellite cells in the proliferation stage. If you were to look at this same plate two days later, it would be completely covered with cells.

– What difficulties did you have to overcome in order to make the cultured meat look and taste as similar to natural meat as possible?

When we presented our first cultured meat hamburger in 2013, we also brought an ordinary beef hamburger with it. And most people that we asked to guess which of these hamburgers contained natural meat were at a loss because they were indeed very similar. But we used a little cunning back then, because the meat we had cultured had yellow fibers as opposed to red ones, so to achieve authenticity we had to dye our hamburger with carmine and saffron. The thing is that meat’s red color comes from a protein called myoglobin that is contained in muscular tissue: it becomes red in the presence of oxygen or blue in its absence. When we cultured our first cells, they were exposed to ordinary ambient air that we breathe. The oxygen content in it was excessive for cell culture, so they turned yellow. Later we developed a method that limits oxygen supply to cells, thus allowing us to stimulate the development of myoglobin and make the meat fibers pink.

Also, our «pilot model» of a hamburger did not have any fat tissue, so it had a slightly bland taste. But now we also culture fat tissue out of stem cells, which makes the meat taste richer. But we are not intending to stop there either. So, while we started with culturing small muscle fibers that are good for minced meat products such as hamburger patties (and by the way this type of products take up about 50% of the total meat consumption), now we are working on culturing a real steak. Our goal is to produce real meat, not some artificial substitute. We already have more than enough vegetable protein-based meat substitutes. We are trying to achieve absolute similarity: in taste, in texture, in color.

– How much time is required to culture meat using your method?

To culture the amount of meat sufficient to make 1 hamburger out of one stem cell you will need 90 days, or 3 months. But this is an exponential process, and because each cell duplication takes approximately 1 day, this means that to culture two hamburgers you will need 91 days, 92 to culture four, 93 to culture eight. And so on. In other words, the amount of meat we culture doubles day by day.

© Mosa Meat

– How soon do you think cultured meat is going to be available and affordable for the general public?

The cost of the first hamburger with cultured meat was $325,000. To make cultured meat a product with a competitive price, we will need to scale the production, and that will probably take quite a long time. After scaling the production, the price of one such hamburger will probably be around 10 euros. But if we also improve the technology, then the price could go down to the cost level of an ordinary hamburger or possibly even lower than that.

So, right now we need to organize the production in the most efficient way. It has to be more efficient than traditional beef production, as well as environmentally safe and sustainable. As of now, culturing stem cells is a very demanding process and also not a very environmentally friendly one because it requires using large amounts of plastic. So, when we think about commercial production, we see a possibility of culturing meat in bioreactors — large vats with the volume of 25 thousand liters each, that are essentially huge fermenters — while the cells themselves could be placed on reusable microcarriers. For the record, one such reactor is sufficient to provide enough food supply for 40 thousand people per year.

If the reproduction of cells is expanded to a commercial level, then our second big task is to learn how to culture cells without using serum. Serum is basically blood with no cells in it, and we also get it from cows. We have done some experiments with cells by culturing them without serum, and we have found certain conditions in which cells grow really well even without it, but we still need to work on the efficiency of this method. Besides, when scaling this project, we are planning to use photosynthetic seaweed and cyanobacteria as the source of amino acids and sugars. Stem cells are not very picky about their food, so they will consume whatever we give them.

© Mosa Meat

– Do you think that a lot of people will agree to eat this meat, knowing that it was grown in a bioreactor and not on a farm?

Meat that is produced in a laboratory may seem unnatural, off-putting, etc. to a lot of people. And if you take this question to the streets and ask it to some random people there, they will probably say something like: «What, are you crazy? No way I’m going to eat it!» But you can rephrase the question as follows: «Imagine that in about 20 years from now you come to a supermarket and see two products, two different types of meat. One of them has been created in a laboratory, and it costs the same as ordinary meat, tastes the same, has the same color and texture. Right next to it is a piece of ordinary meat, but in addition to its price you will need to pay a special environmental fee, and as a result the total cost is much higher. In addition to that, its package has a fine print that says that some animals had to be killed to produce it. Which one are you going to choose?» And the answer to that question is not going to be as clear-cut as before.

But of course this is an important requirement to our product; we need consumers all over the world to accept it. People are often afraid of the unknown. But there is another thing that needs to be mentioned here. Let me give you an example. A lot of people really love hot dogs, and they buy them from street vendors even though they have no idea how these hot dogs are made. But they are cheap and they are tasty. My point here is that you see a lot of people who eat these hot dogs, and nothing happens to them, so you eat them too. So people accepting any product that is produced using some new groundbreaking method simply requires some time.

Another factor here is the lack of consumer control over the production. But in this case the technology is fairly simple. I think that in the future anybody will be able to culture meat right in their kitchen. You will only need to have a specific device – an incubator of sorts, the size of a microwave oven. And this process is not going to cause you many difficulties, because stem cells turned out to have one more remarkable property: they easily survive when they are dried by way of sublimation. So maybe some day you will be able to go online and order a few small plastic bags with stem cells of a tuna, a cow, a pig, a tiger or any other animal and culture a piece of meat out of them on your own. However, you will have to decide what you want to eat 3 months in advance, because that is how much time that process is going to take. But those are trivial matters.

© Mosa Meat

Cooking first cultured hamburger at London press conference

– How do you think your project might change the way people treat meat?

Food has always been closely connected with culture and human emotions. When we eat meat there is always such aspect as the taste and nutritional value of this meat, but also there is this underlying idea of dominating another species, that hunter instinct that we have had for centuries and that we still possess. And, of course, in this regard people never associate meat production with laboratories and scientists. But when commercial lab production of meat starts, the idea of what meat represents for us is going to inevitably change. Meat will no longer be a product of an animal that we slaughtered or killed when hunting.

Another important nuance is that laboratory meat production can give us vast creative freedom. We will be able to create meat of different shapes and colors, which can make it attractive for children, for example. Besides, it will be possible to change the composition of muscle cells, make fatty acids in them more saturated with Omega elements that are beneficial for human health; in other words, we will be able to make a healthier product, and then it’s quite possible that your doctor will prescribe you 2 visits to McDonald’s per week.  

© Mosa Meat

– In order to put this technology to mass production you will probably need serious investments. How hard is it to obtain funding for this essentially revolutionary project?

Getting government funding is very difficult. But a lot of private investors are highly interested in this project. So we don’t have to go out in the streets and ask for funding, some people offer it to us themselves. Investors understand that this is going to be a huge market, and if it succeeds then its advantages for most people are quite obvious. And a lot of organizations that invest into us also finance other companies that work in this sphere, such as Memphis Meats or SuperMeat. In their opinion, it makes no sense to just let companies compete with each other; they should be able to exchange valuable information. Then the development is going to go much faster.

– And finally: what short-term goals have you set before you?

As I already mentioned, right now we are working on culturing a steak, which has a more complex structure than a hamburger patty. It’s more complex because the thicker the muscular tissue, the more deprived of oxygen and nutritious substances the cells are inside it, which is why the cells can die. Humans and other mammals have blood vessels in their bodies, which supply oxygen and nutritious substances to organs and tissue cells. The tissue that we culture does not have any blood in it, but we are still in need of a system of canals and perfusion that will enable nutritious substances and oxygen to reach every small part of our tissue. This is a serious scientific challenge, but I don’t see any reasons not to overcome it.

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