Harmful bacteria now on fresh produce.

The same bacteria that can make an undercooked burger deadly or an underdone chicken stomach churning are getting onto raw fruits and vegetables at a quick enough pace that both government and industry are stepping up efforts to keep fresh produce uncontaminated from farm to supermarket. "We've seen 4 outbreaks of foodborne illness associated with lettuce this year alone," says Jeremy Sobel, MD, a medical epidemiologist at the Centers for Disease Control and Prevention. The culprit: E coli 0157:57, the deadly strain of bacteria in the notorious Jack-in-the-Box incident of 1992.

Other outbreaks of foodborne illness in recent years have come from Salmonella bacteria on …