By HENRY FOUNTAIN
MAASTRICHT, the Netherlands — As a gastronomic delicacy, the five-ounce
hamburger that Mark Post has painstakingly created here surely will not
turn any heads. But Dr. Post is hoping that it will change some minds.
The hamburger, assembled from tiny bits of beef muscle tissue grown in a
laboratory and to be cooked and eaten at an event in London, perhaps in
a few weeks, is meant to show the world — including potential sources
of research funds — that so-called in-Vitro meat, or cultured meat, is a
reality.
“Let’s make a proof of concept, and change the discussion from ‘this is
never going to work’ to, ‘well, we actually showed that it works, but
now we need to get funding and work on it,’ “ Dr. Post said in an
interview last fall in his office at Maastricht University.
Down the hall, in a lab with incubators filled with clear plastic
containers holding a pinkish liquid, a technician was tending to the
delicate task of growing the tens of billions of cells needed to make
the burger, starting with a particular type of cell removed from cow
necks obtained at a slaughterhouse.
The idea of creating meat in a laboratory — actual animal tissue, not a
substitute made from soybeans or other protein sources — has been around
for decades. The arguments in favor of it are many, covering both
animal welfare and environmental issues.
A 2011 study
in the journal Environmental Science and Technology, for example,
showed that full-scale production of cultured meat could greatly reduce
water, land and energy use, and emissions of methane and other
greenhouse gases, compared with conventional raising and slaughtering of
cattle or other livestock. Those environmental arguments will only gain
strength, advocates say, as worldwide demand for meat increases with
the rise of middle-class populations in China and elsewhere.
Dr. Post, one of a handful of researchers in the field, has made strides in developing cultured meat through the use of stem cells
— precursor cells that can turn into others that are specific to muscle
— and techniques adapted from medical research for growing tissues and
organs, a field known as tissue engineering. (Indeed, Dr. Post, a
physician, considers himself first and foremost a tissue engineer, and
about four-fifths of his time is dedicated to studying how to build
blood vessels.)
Yet growing meat in the laboratory has proved difficult and devilishly
expensive. Dr. Post, who knows as much about the subject as anybody, has
repeatedly postponed the hamburger cook-off, which was originally
expected to take place in November. His burger consists of about 20,000
thin strips of cultured muscle tissue. Dr. Post, who has conducted some
informal taste tests, said that even without any fat, the tissue “tastes
reasonably good.” For the London event he plans to add only salt and
pepper.
But the meat is produced with materials — including fetal calf serum,
used as a medium in which to grow the cells — that eventually would have
to be replaced by similar materials of non-animal origin. And the
burger was created at phenomenal cost — 250,000 euros, or about
$325,000, provided by a donor who so far has remained anonymous.
Large-scale manufacturing of cultured meat that could sit side-by-side
with conventional meat in a supermarket and compete with it in price is
at the very least a long way off.“This is still an early-stage
technology,” said Neil Stephens, a social scientist at Cardiff
University in Wales who has long studied the development of what is also
sometimes referred to as “shmeat.” “There’s still a huge number of
things they need to learn.”
There are also questions of safety — though Dr. Post and others say
cultured meat should be as safe as, or safer than, conventional meat,
and might even be made to be healthier — and of the consumer appeal of a
product that may bear little resemblance to a thick, juicy steak.
“This is something very new,” Dr. Stephens said. “People need to wrestle with the idea of whether this is meat or not.”
Dr. Post is well aware of the obstacles. “I see the major hurdles,
probably better than anybody else,” he said. “But you’ve got to have
faith in technological advances, that they will be solved.”
And as with any technology, costs should eventually come down. “If it
can be done more efficiently, there’s no reason why it can’t be
cheaper,” he said. “It has to be done using the right materials,
introducing recycling into the system, controlling labor through
automation.”
Cultured meat would have some inherent cost advantages over conventional
meat, said Hanna Tuomisto, whose research while at the University of
Oxford in England was the basis for the Environmental Science and
Technology study. “It’s really about the conversion of feed to meat,”
she said. “In cultured meat production it’s much more efficient; only
the meat is produced, and not all the other parts.”
Gabor Forgacs, a researcher at the University of Missouri and a founder of Modern Meadow,
a start-up company that wants to develop and market cultured meat, is
aware of the hurdles as well. “Getting cultured meat to the supermarket
is going to be difficult, and controversial,” said Dr. Forgacs, whose
approach to cultured meat has some similarities to Dr. Post’s, although
he has also developed 3-D bioprinting technologies that might someday be
used to create thicker tissues.
Given the difficulties, Modern Meadow is first focusing on creating
cultured leather. Its process does not use stem cells but rather skin
fibroblasts, specialized cells that produce collagen. “There are a lot
of parallels to cultured meat, except that it is a lot less
controversial because you’re not going to eat it,” Dr. Forgacs said.
“But if we can convince the universe that we can build leather, it will
be much easier to convince the universe that we can build meat.”
In his work on cultured meat, Dr. Post uses a type of stem cell called a
myosatellite cell, which the body itself uses to repair injured muscle
tissue. The cells, which are found in a certain part of muscle tissue,
are removed from the cow neck and put in containers with the growth
medium. Through much trial and error, the researchers have learned how
best to get the cells to grow and divide, doubling repeatedly over about
three weeks.
“But we need billions,” said Anon van Essen, the technician in Dr. Post’s lab.
The cells are then poured onto a small dab of gel in a plastic dish. The
nutrients in the growth medium are greatly reduced, essentially
starving the cells, which forces them to differentiate into muscle
cells. “We use the cell’s natural tendency to differentiate,” Dr. Post
said. “We don’t do any magic.”
Over time the differentiated cells merge to form primitive muscle
fibers, called myotubes. “And then they just start to put on protein,”
Dr. Post said, and organize themselves into contractile elements. The
key to this self-organization, he said, is that the cells are anchored
in place (using a technique that he declined to disclose; earlier in his
work he used Velcro). “We add anchor points so they can attach to
something and start to develop tension,” he said. “That is by far the
biggest driver of protein synthesis, and they do that by themselves.”
The result is a tiny strip of tissue, about half an inch long and only
1/25th of an inch in diameter, that looks something like a short pink
rice noodle, Dr. Post said.
The strips have to be thin because cells need to be close to a supply of
nutrients to stay alive. One approach to making thicker tissues — to
make a cultured steak rather than a hamburger, for instance — would
require developing a network of channels, the equivalent of blood
vessels, to bring nutrients to each cell. (A steak would also require
culturing fat and incorporating it in the tissue, something Dr. Post has
not had to do with his burger.)
Dr. Post said that one advantage of using myosatellite cells is that
they differentiate easily. “The satellite cell is the ideal cell,” he
said. “You don’t have to pull a lot of tricks to let it differentiate. I
also think it’s a practical advantage of keeping a lot of the stem cell
production and quality control in the animal itself.”
But others note that since there is a limit to how often myosatellite
cells can reproduce, Dr. Post’s cultured meat will never be completely
animal-free; he will always need a supply of muscle tissue from which to
obtain new cells.
Other researchers are studying different kinds of stem cells that,
unlike myosatellite cells, can reproduce indefinitely, ensuring a
“livestock-autonomous” supply of cells to make cultured meat. Dutch
researchers at Utrecht University are trying to isolate embryonic stem
cells from pigs and cows. And Nicholas Genovese of the University of
Missouri is trying to develop a type of stem cell that is “induced” from
a regular adult cell. So a skin cell from a pig, perhaps, could be
turned into a stem cell that could reproduce indefinitely and
differentiate into muscle tissue to create cultured pork.
But Dr. Post said that efforts to use different kinds of stem cells
introduced other problems. And even if his approach means the world will
still need cattle, it will need far fewer of them. “If we can reduce
the global herd a millionfold, then I’m happy,” he said. “I don’t need
to reduce it a billionfold.”
Anyway, he said, “a lot of the technologies in the process we are
currently using eventually have to be changed, if not all of them.
“That’s not the point of the proof of concept,” Dr. Post said. “The
point is, we already have sufficient technology to make a product that
we could call meat or cultured beef, and we can eat it and we survive.”
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