To the scientists involved, that failure seems shortsighted. “I think [in vitro meat] will be the only choice left,” says Mark J. Post, head of the physiology department at Maastricht University. “I’m very bold about this. I don’t see any way you could still rely on old-fashioned livestock in the coming decades.”
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In theory, an in vitro meat factory would work something like this: First, technicians would isolate embryonic or adult stem cells from a pig, cow, chicken or other animal. Then they would grow those cells in bioreactors, using a culture derived from plants. The stem cells would divide and redivide for months on end. Technicians would next instruct the cells to differentiate into muscle (rather than, say, bone or brain cells). Finally, the muscle cells would need to be “bulked up” in a fashion similar to the way in which animals build their strength by exercising.
For now there are challenges at every stage of this process. One difficulty is developing stem cell lines that can proliferate for long periods without suddenly deciding they want to differentiate on their own. Another challenge is to be sure that when stem cells are prompted to differentiate, the overwhelming majority of them turn into muscle as instructed. “If 10 cells differentiate, you want at least seven or eight to turn into muscle cells, not three or four,” Roelen says. “We can achieve 50 percent now.”
The Utrecht scientists tried to extract and develop embryonic stem cell lines from pigs. Such cells would, in normal conditions, be able to duplicate every day for long periods, meaning 10 cells could grow into a staggering amount of potential meat in just two months—more than 50,000 metric tons. “Culturing embryonic stem cells would be ideal for this purpose since these cells have an (almost) infinite self-renewal capacity,” according to a 2009 report by the Utrecht team. “In theory, one such cell line would be sufficient to literally feed the world.”
Until now, however, such cell lines have been developed only from mice, rats, rhesus monkeys and humans. Embryonic cells from farm animals have had a tendency to differentiate quickly—and of their own accord—into specialized cells. In the report, Utrecht team’s porcine cells often veered toward “a neural lineage”—brains, not bacon.
The Utrecht group also worked with adult stem cells, which have the advantage of being largely preprogrammed. These cells exist within skeletal muscle (as well as other parts of the body) with a specific mission: to do repair work when tissue is injured or dies off. So if you are making in vitro meat and want stem cells that will almost surely turn into muscle tissue, adult stem cells from skeletal muscle tissue should work very well. Until now, however, scientists have not been able to get these cells to proliferate as readily as they can embryonic cells.
Cost is another barrier. The culture used to grow stem cells of any kind is very expensive. With currently available media, it might cost $50,000 to produce a pound of meat, according to Roelen, and the most efficient nutrient bath is derived from fetal calf or horse serum taken from slaughtered animals. In recent years scientists have developed their own recipes for “chemically defined media” that include no animal products. By using recombinant-DNA technology, they have also been able to get plant cells to produce animal proteins that could be used to grow the meat. But both these types of media are, for now, prohibitively expensive. An algae-based medium may eventually work best because algae can produce the proteins and amino acids necessary to sustain cell life, but that, too, is costly—at least for now.
Once the researchers get a big supply of muscle cells, they will need to keep them alive and bulk them up. It is possible now to engineer a thin strip of tissue, but if it gets thicker than a few cell layers, parts of it start to die off. The cells need a constant flow of fresh nutrients to stay alive. In the body, these nutrients are delivered by the bloodstream, which also removes waste. Post is working on how to develop a three-dimensional system that delivers such nutrients.
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14 Comments
Add CommentSlaughtering other creatures so we can eat them is horribly barbaric. I look forward to doing away with that practice.
Reply | Report Abuse | Link to this"According to a 2006 report by the Food and Agriculture Organization, the livestock business accounts for about 18 percent of all anthropogenic greenhouse gas emissions" This 18% figure has been widely debunked. It was based on false assumptions about land use. The real percentage is about half that. While 9% is still significant, even that can be mostly eliminated if the animals were raised in an appropriate (but more expensive) way.
Reply | Report Abuse | Link to thisI do hope growing meat in a dish does eventually work. Unfortunately, such meat would probably need antibiotics, which is the only reason why I wouldn't eat it. For health reasons I don't eat much meat anyway, so it isn't much of an issue.
While making choices that reduce greenhouse gases is a good thing and everyone should do it, realistically there's no way it'll be enough to stop global warming. It may be enough to slow it down a bit, which has some value, but not stop it. Humanity will survive, as we always adapt to new changes, but many other species will go extinct, and it will cost us a lot of money.
It seems to me that the idealism of being able to duplicate nature's steaks is misguided and counter productive.
Reply | Report Abuse | Link to thisWe don't need to limited ourselves to creating product identical to nature's own. We need to start with creating as close a product as possible and using other methods of processing to then shape it into something like 'meat.
Then we can move forward in steps to the possibility of getting closer to the 'real' thing, IF the intermediary product is not good enough.
Who knows ? People might well be more than satisfied with an intermediary product.
By limiting this research work to only duplicating nature, we are holding back the core goal of this whole research process - to produce a product that enables us to reduce the numbers of animals we slaughter for meat.
I invite people to look for and read a scifi story involving "chicken little."
Reply | Report Abuse | Link to thisReading about food in Sci Am lately one might think there is an implicit assumption that meat and other animal protein is essential for human health. Nothing could be further from the truth. Most Americans get far too much protein as it is and would be much healthier eating only plant-based foods. There is a protein myth propagated by the meat dairy industry and it's virtual proxy, the USDA. Their propaganda is based on no research, in fact, ignores research to the contrary. Fact: there is no need for animal protein. We would be far healthier without it. For a great review of this topic read T. Colin Campbell's "The China Study". It changed my life. What I learned in grade school and medical school about nutrition was paid for by industry and just plain wrong.
Reply | Report Abuse | Link to thisReplacing real meat with cultured meat, while maybe reducing animal cruelty, would likely consume huge amounts of energy to grow and contribute at least as much to global warming. There is far too much industrial food as it is now. Let's just eat plants and live low on the food chain. We would all live longer and the planet would be better off.
George T, MD
Plant based diets are the most effective, but lab grown meat could be of use in deterring murder (murder should be illegal outright)... similarly, sex robots could be made to stop rapists (no joke there).
Reply | Report Abuse | Link to thisYou wrote:
Reply | Report Abuse | Link to this"Replacing real meat with cultured meat, while maybe reducing animal cruelty, would likely consume huge amounts of energy to grow and contribute at least as much to global warming."
Well I don't know how ultimately accurate this article is ... but they claim the following in the article above:
"if scientists grew the muscle cells in a culture of cyanobacteria hydrolysate (a bacterium cultivated in ponds), would involve “approximately 35 to 60 percent lower energy use, 80 to 95 percent lower greenhouse gas emissions and 98 percent lower land use compared to conventionally produced meat products in Europe.”"
That seems to be the answer to your concern.
As the article mentioned, the concept of slaughter-free meat was originally brought into the public eye by PETA’s $1 million prize offering to the first R&D team to produce commercial quantities of meat grown in vitro. It is also important to note that, in the absence of Federal funding for cultured meat development in the United States, PETA is directly supporting the only currently active academic research toward this emerging technology. In both concept and implementation, PETA has taken on a pioneering role in cultured meat development.
Reply | Report Abuse | Link to thisI think that the idea of growing protein in bioreactors is a good one.
Reply | Report Abuse | Link to thisHowever the idea that "much of the 30% of ice free land can be converted to other uses" needs looking at. Quite a lot of it is desert. Quite a lot is semi-arid, and only suitable for extensive livestock grazing.
On the other hand a lot of the meat that is consumed in advanced countries such as the USA is raised in feed lots, sometimes in appalling conditions, on grains which are suitable for human consumption.
I myself really like the idea of creating muscle in a vat...who knows whats next...a heart..a kidney(etc.)
Reply | Report Abuse | Link to thisFor the vegetarians posting...not interested..don't get me wrong, I love my veggies and my fruit, but I also love a great steak or even a great hamburger...
ps..the hearts and kidneys would be for transplants not eating...yech;-)
And what if the only line that can efficiently produce edible, nutritious, and tasty flesh is human? No animals (humans included) would have to be slaughtered. Except for the “yuck” factor, this would be humane. A question for the ethicists.
Reply | Report Abuse | Link to thisThere is really only one word for "Inside the Meat Lab" written by journalist Bartholet (as unfortunately are so many of your articles these days); silly.
Reply | Report Abuse | Link to thisWhile the author correctly points out how wasteful traditional production of beef is, the discussion of growing meat in a lab is very poorly reported. There is no discussion of the possible conversion rate (the ratio of feed input to meat output – typically over 6 for beef today) of the mythical process, nor where the "culture of cyanobacteria" comes from or how much it would cost or what the inputs for it would be.
As every vegan knows (and I know some quite chubby ones) there are many very acceptable meat substitutes commercially available today that do a creditable job of mimicking meat with a conversion rate of 1. Farmed fish produce marketable fish with conversion rates below 1.5 and a GMO salmon awaiting FDA approval can bring that ratio to close to 1.25. Why waste scarce research dollars on pie in the sky ideas such as lab grown meat? To what advantage even if it could be made to work?
The one bit of good news in the article is that NASA, which often pursues some pretty nutty ideas, at least was smart enough to stop throwing money on this one!
This is bizarre. Just as factory farming of all kinds lowers the costs and the nutritional density of our foods this is just another step backwards. We've already lowered the variety of the foods we eat to an all time low. Having beef from one genetic line (the one that produces the best) is not going to improve nutrition, I'm thinking.
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