What if the next burger you ate was created in a warm, nutrient-enriched soup swirling within a bioreactor? Edible, lab-grown ground chuck that smells and tastes just like the real thing might take a place next to Quorn at supermarkets in just a few years, thanks to some determined meat researchers. Scientists routinely grow small quantities of muscle cells in petri dishes for experiments, but now for the first time a concentrated effort is under way to mass-produce meat in this manner.

Henk Haagsman, a professor of meat sciences at Utrecht University, and his Dutch colleagues are working on growing artificial pork meat out of pig stem cells. They hope to grow a form of minced meat suitable for burgers, sausages and pizza toppings within the next few years. Currently involved in identifying the type of stem cells that will multiply the most to create larger quantities of meat within a bioreactor, the team hopes to have concrete results by 2009. The 2 million euro ($2.5 million) Dutch-government-funded project began in April 2005. The work is one arm of a worldwide research effort focused on growing meat from cell cultures on an industrial scale.

"All of the technology exists today to make ground meat products in vitro," says Paul Kosnik, vice president of engineering at Tissue Genesis in Hawaii. Kosnik is growing scaffold-free, self-assembled muscle. "We believe the goal of a processed meat product is attainable in the next five years if funding is available and the R&D is pursued aggressively."

A single cell could theoretically produce enough meat to feed the world's population for a year. But the challenge lies in figuring out how to grow it on a large scale. Jason Matheny, a University of Maryland doctoral student and a director of New Harvest, a nonprofit organization that funds research on in vitro meat, believes the easiest way to create edible tissue is to grow "meat sheets," which are layers of animal muscle and fat cells stretched out over large flat sheets made of either edible or removable material. The meat can then be ground up or stacked or rolled to get a thicker cut.