But obstacles remain to commercially brewed beef—most significantly, cost and taste. "To get enough protein to make a hamburger is going to cost you thousands of dollars," says Douglas McFarland, a distinguished professor of muscle biology at South Dakota State University who collaborated with Matheny on a 2005 analysis of the feasibility of in vitro meat in Tissue Engineering. Matheny estimates that in vitro chicken could be produced for about $5,000 a ton, about twice the cost of conventional chicken. He acknowledges that it won't happen unless governments or nonprofits subsidize research and development.
Unfortunately, cutting live animals out of the equation doesn't remove all the ethical problems. Like all scientists doing tissue engineering, McFarland uses commercially produced growth factors to get his turkey and chicken muscle cells to flourish. Growth factors are either extracted from animal blood, which makes them offensive to animal-rights advocates, or are synthesized using molecular biology, which makes them expensive. Matheny says the lack of affordable nonanimal growth factors is the biggest challenge facing in vitro meat.
Lab meat also needs exercise before it is fit for the fork. Meat's distinctive texture is formed by the stretching and flexing of muscle fibers as the animal moves. Researchers at the Eindhoven University of Technology in the Netherlands are trying to design bioreactors that would house the equivalent of bench-press machines for cells. Their effort is part of a multiyear project to develop commercially viable in vitro meat funded by the Dutch government. Henk Haagsman, a professor of meat sciences at Utrecht University who is leading the project, says his group hopes that in six years it will have produced a ground-meat-like product that could be used in pizzas or sauces.
Even if lab-grown meat can soon be grown in abundance, it will still have to taste good. That may prove to be the biggest challenge of all. One of the very few people to have eaten in vitro meat is Oron Catts, a 40-year-old artist who directs SymbioticA, an art and science collaborative research center at the University of Western Australia. Catts and collaborator Ionat Zurr grew frog steaks in vitro for an installation and performance in Nantes, France, in 2003 called "Disembodied Cuisine."
The artists used tissue engineering to grow two quarter-size disks of muscle on a polymer scaffold, then sautéed the steaks in a honey-garlic sauce, quartered them, and served dinner for eight. It was not a gourmet experience. The scaffold didn't degrade enough, Catts says, and the unexercised muscle had a texture reminiscent of snot. "It was fabric with jelly," he says. "Four people spit out the bits." That was five years ago, and he hasn't eaten meat since.