The pork was a bridge too far. Once people found out about the pork skins, many rabbis had to retract their endorsements of the jiggly dessert. The whole episode underscored how industrialization was changing food. “They didn’t realize the door they opened by allowing these transformed products,” says Horowitz. “That’s why the dominant kosher certifiers closed the door when they realized they were on a slippery slope.”
Post, at Maastricht, originally used animal-based collagen to grow beef, but he’s now experimenting with polymers from plants, seaweed, and mushroom. Others have tried edible protein in tofu and Quorn, the meat substitute derived from a fungus. But while muscle cells naturally take to collagen—just as they do in an animal’s body—they don’t quite fit right with plant-based proteins. It’s possible, says Post, but “it needs a couple of tricks.”
3. Lab-grown meat uses fetal cow blood
Keeping animal cells alive in a dish is tricky, and the magic ingredient has long been fetal bovine serum, which is derived from the blood of unborn calves. It’s rich in the proteins and nutrients that animal cells need. It’s also a byproduct of industrial farming, as the serum comes from fetuses found inside cows being slaughtered.
This is a problem because lab-grown meat can’t rely on byproducts of industrial farming if it is going to replace industrial farming—and the serum is unlikely to be kosher. That’s because the cows mostly likely to be pregnant with a fetus at the time of slaughter, says Cornell food science professor Joe Regenstein, are dairy cows being culled due to age or disease. And cows that are too sick at the time of slaughter will not pass kosher inspection.
The good news, though, is that companies supplying biology labs do make animal-free serum substitutes. The bad news is that nobody knows exactly what is inside those alternatives, not even the researchers who use them. (It’s probably some combination of stuff derived from plants, bacteria, or yeast.) “It’s actually proprietary,” says Post, who uses these animal-free alternatives in his lab. “The commercial sources don’t reveal it, and it’s a little bit annoying that we’re working with a blackbox.” In Post’s experience, the animal-free substitutes do work, though cells grow a little differently than they do with fetal bovine serum.
The mystery of that’s inside the serum substitutes may be annoying for researchers, but it will be a real problem for food regulators. A typical serum substitute might contain over a dozen ingredients, and under kosher law, someone would have to trace each and every ingredient to make sure it was made in a kosher facility. It’s just like if you wanted to sell pizza as kosher: the flour, yeast, tomato sauce, and cheese all need to be kosher certified. “I don’t think it’s trivial to have a kosher cell culture,” says Regenstein.