FROM SCIENTIFIC AMERICAN
Meat grown in bioreactors - instead of raised on farms - could help alleviate planetary stress. In 2010 Hanna Tuomisto, then at the University of Oxford, coauthored a study of the potential environmental impacts of cultured meat. The study found that such production, if scientists grew the muscle cells in a culture of cyanobacterium hydrolysate (a bacteria cultured 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."
In theory, an in vitro meat factory would work like this. First, technicians would isolate embryonic or adult stem cells from a pig, cow, chicken or other animal. Then they would grow those 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.
But tissue engineers have come up with multiple problems. When stem cell lines proliferate for long periods, many cells suddenly decide on their own to differentiate. And of those cells that do wait for the external signal to differentiate, many do not turn into muscle as instructed.
Embryonic cells from farm animals have a tendency to differentiate quickly - and of their own accord - into specialized cells. The Utrecht team's porcine cells often veered toward " a neural lineage" - brains, not bacon.
Cost poses another barrier. The culture used to grow stem cells of any kind is very expensive. In 2011 Roelen estimated that cultured meat cost $50,000 a pound - and it was not acceptable to vegetarians, because the nutrient baths were derived from fetal calf or horse serum taken from slaughtered animals. But scientists have since developed recipes for "chemically defined media" that include no animal products. They have also been able to genetically engineer plant cells to produce animal proteins that could be used to grow the meat. Both these types of media remain prohibitively expensive.
Professor Mark Post first got involved in a Dutch government-funded program investigating “in vitro meat” in 2008, when he was a professor of tissue engineering at the Eindhoven University of Technology. The program had been initiated by Wilem van Eelen, an 86-year-old entrepreneur who held a long-time fascination for the possibility of culturing meat.
When the director of the programme fell ill, about mid-way through the program, Post took over supervision of the PhD students. Motivated by the potentially high societal impact, he continued research even after the funding had ended in 2010.
Renewed funding by a private partner enabled the realisation of a project to create a processed meat product using muscle cells from a cow.
Professor Post received his medical degree from the University of Utrecht in 1982 and trained for a PhD in Pulmonary Pharmacology, graduating from the University of Utrecht in 1989.
He joined the KNAW Interuniversity Cardiology Institute of the Netherlands before being appointed full-time Assistant Professor in Medicine at Harvard Medical School, Boston, MA in 1996. Five years later, he moved with his lab to Dartmouth Medical School, Hanover, NH, and was appointed Associate Professor of Medicine and of Physiology.
In July 2002, Dr. Post returned to the Netherlands as a Professor of Vascular Physiology at Maastricht University and Professor of Angiogenesis in Tissue Engineering at the Technical University Eindhoven. Since January 2004 he has been Chair of Physiology and Vice Dean of Biomedical Technology at Maastricht University.
An algae - based medium may eventually work best because algae can produce the proteins and amino acids necessary to sustain life. But that, too, is costly - at least for now.
Post has optimistically estimated that large - scale production of in vitro meat could lower the price to about $10 a pound and that coming advances in the technology will reduce costs even further.
By 2011 only about half of the stem cells were turning into muscle on command. Once researchers are able to produce a big supply of muscle cells, they will need to keep the cells alive and bulk them up.
It is possible now to assemble cells into a thin strip of tissue, but when the layer gets more than a few cell layers thick, parts of it start to die off. The cells need a constant flow of fresh nutrients to stay alive. Scientists have tried stimulating the tissue with electrical pulses. But it is costly and inefficient, bulking up the cells by only about 10 percent.
Breakthroughs in all these areas will take money, which so far has come in unpredictable bursts, mainly from private sources. In 2008 PETA offered $1 million to anyone who could grow commercially viable chicken in a lab by 2012. The deadline was later extended to 2014, but the money still went unclaimed. A Brooklyn - based start - up called Modern Meadow recently raised $10 MILLION in venture capital to fund its quest to make cultured leather and meat.
Cor van der Weele of Wageninger University noted that people often associate cultured meat with two other ideas: genetically modified foods - which are often seen, particularly in Europe, as a dangerous corporate scheme to dominate or control the food supply - and negative perceptions of the meat industry in general, with its factory farms, disease and mistreatment of animals. Once people realize that cultured meat is not genetically modified and could be a clean, animal - friendly alternative to factory farms, she says, "the scared , very negative response is often very fleeting."
1.) Researchers isolate embryonic or adult stem cells from a healthy pig, cow or chicken.
2a.) Stem cells taken from an embryo are easy to make proliferate, but hard to coax into muscle cells.
2b.) Conversely, adult stem cells taken from muscle tissue are difficult to grow, but easier to convert into muscle form.
3.) Scientists induce the stem cells to multiply many times over by culturing them in a bacterial - based growth serum. Embryonic cells are prodded to form muscle cells.
4.) The cells are placed on a scaffold where they form muscle fibers. Applied tension exercises the cells, bulking them up.
5.) The cells are harvested and consumed. The thin strips of meat will make their first appearance in a processed product such as sausage or ground beef - not as a steak.
WIKIPEDIA DEFINITION of IN VITRO MEAT:
In vitro meat, also called victimless meat, cultured meat, tubesteak, cruelty-free meat, shmeat, and test-tube meat, is an animal-flesh product that has never been part of a living animal with exception of the fetal calf serum taken from a slaughtered cow. In the 21st century, several research projects have worked on in vitro meat in the laboratory. The first in vitro beefburger, created by a Dutch team, was eaten at a demonstration for the press in London in August 2013. There remain difficulties to be overcome before in vitro meat becomes commercially available. Cultured meat is prohibitively expensive, but it is expected that the cost could be reduced to compete with that of conventionally obtained meat as technology improves. In vitro meat is also a cultural issue. Some argue that it is less objectionable than traditionally obtained meat because it doesn't involve killing and reduces the risk of animal cruelty, while others disagree with eating meat that has not developed naturally.