Bacon isn't great for your heart, but it's a heck of a lot worse for the environment. Unlike cows and sheep, pigs lack the enzyme that breaks down phosphorus compounds in plant-based feed. As a result, the runoff from hog farms dumps millions of tons of phosphorus-tainted waste into the soil. From there it leaches into groundwater, eventually finding its way to rivers and lakes, where it causes algae blooms that suffocate aquatic animals.
But biologists at Canada's University of Guelph have figured out how to slip a phosphorus-digesting enzyme from a bacterium into a pig's DNA. The transgenic hogs produce manure containing 75 percent less phosphorus—cleaner even than manure from pigs fed costly enzyme supplements. "Once the gene has been incorporated into the stock, it won't cost farmers anything," Cecil Forsberg says. It will be at least five years before the FDA lets the nonpolluting piggies go to market. Meanwhile, Forsberg is turning his attention to the problem of barnyard odor. "We're going to start tests soon to see if there's any corresponding reduction in smell," he says.