78 Time November 8/November 15, 2021
pig pancreases: identify and isolate the stem cells—the
chameleon- like building blocks of animal biology—prod
them to create the desired tissue, and then encourage
them to proliferate by feeding them a cell- culture me-
dium made up of amino acids, sugars, salts, lipids and
growth factors. Scientists have been trying for years to
use the same process to grow artificial organs, arteries
and blood vessels, with mixed results.
Post, a vascular cardiologist, used to be one of those
scientists. He jokes that stem-cell meat, unlike or-
gans, doesn’t have to function. On the other hand, it
has to be produced in massive amounts at a reasonable
cost, and pharmaceutical companies have spent de-
cades and billions of dollars attempting—and largely
failing—to scale up stem-cell production to a fraction
of what it would take to make cultivated meat afford-
able. If cellular- agriculture companies succeed where
so many others have failed, it could unlock a com-
pletely new way of feeding human beings, as radical
a transformation as the shift from hunting to domes-
ticating animals was thousands of years ago. Despite
investor enthusiasm, that’s still a big if; Eat Just, the
company closest to market, is producing only a cou-
ple hundred pounds of cultivated chicken a year.
Many of the scientists at Mosa reflexively attribute
sentience to the cells they are working with, discussing
their likes and dislikes as they would those of a fam-
ily pet. Fat tissue can handle temperature swings and
rough handling; muscle is more sensitive and needs ex-
ercise. “It’s like producing cows on a really microscopic
scale,” says Laura Jackisch, the head of the Fat Team.
“We basically want to make the cells as comfortable as
possible.” That means fine- tuning their cell- culture me-
dium in the same way you would regulate a cow’s feed
to maximize growth and health. For one biopsy to reach
the 4.4 billion lb. of meat in Post’s theoretical scenario,
it would have to double 50 times. So far, Jackisch’s team
has made it to the mid-20s.
A lot of that has to do with the quality of the
growth medium. Until recently, most cultivated- meat
companies used a cell culture derived from fetal bovine
serum (FBS), a pharmaceutical- industry staple that
comes from the blood of calf fetuses, hardly a viable
ingredient for a product that is supposed to end animal
slaughter. The serum is as expensive as it is controversial,
and Jackisch and her fellow scientists spent most of the
past year developing a plant-based alternative. They
have identified what, exactly, the cells need to thrive,
and how to reproduce it in large amounts using plant
products and proteins derived from yeast and bacteria.
“What we have done is pretty breathtaking,” she says.
“Figuring out how to make a replacement [for FBS]C S G
Once stem
cells are
isolated from
the biopsy
and fed a
nutrient-
dense growth
medium, they
thicken into
filaments
of fat. Once
mature,
they can be
blended with
cultivated
muscle cells
to create
a product
similar to
ground beef