Experts mystified by cookie dough outbreak

Federal microbiologists and food safety investigators have descended on the Danville, Va., plant that makes Nestle’s refrigerated cookie dough, trying to crack a scientific mystery surrounding a national outbreak of illness from E. coli 0157:H7, a deadly strain of bacteria, which has been linked to the product.

Health officials and food producers puzzled Saturday over how E. coli 0157:H7, a bacterium that lives in the intestines of cattle, could have ended up in a product that seems so unlikely to contain it.

“It’s a fascinating outbreak,” said Craig Hedberg, an expert on food-borne diseases at the University of Minnesota. “By just looking at package labeling, there is no reason you would expect an event like this to occur.”

The outbreak, which has sickened at least 65 people in 29 states, is the latest worry for consumers across the country unnerved by a wave of food-borne illnesses, including botulism associated with canned chili and infections from salmonella linked to peanut products.

The outbreak comes as the federal government is attempting to revamp the nation’s food safety system. President Barack Obama has identified food safety as a priority, and Congress is moving legislation that places new requirements on food manufacturers while beefing up the Food and Drug Administration’s inspection and enforcement powers.

Nestle has a solid reputation within the food industry for manufacturing practices designed to prevent contamination. The company recalled all its refrigerated Toll House cookie dough products, or about 300,000 cases, on Friday, within 24 hours of being notified by the FDA that it suspected a problem, said Laurie MacDonald, a vice president at Nestle USA.

The company also suspended operations at the Danville plant that day.

Investigators have not confirmed the presence of E. coli 0157:H7 in any Nestle product; they are testing samples of dough collected from the plant as well as from victims. But William Keene, chief epidemiologist for the state of Oregon, said he was “100 percent” certain that the culprit was the cookie dough. “Virtually everyone (who got sick) ate the same brand of cookie dough,” he said.

Because the appearance of E. coli 0157:H7 in cookie dough is so unusual, investigators are looking at a broad range of possible factors, analyzing the ingredients, the plant’s equipment and interior, the health of workers and whether the facility is located near cattle. Federal officials are also considering whether the dough might have been intentionally contaminated.

State health officials first noticed cases of E. coli 0157:H7 emerging in March. Initially, they suspected ground beef or strawberries. But after interviewing victims, state officials and the CDC compared notes Tuesday and settled on the refrigerated cookie dough as the prime suspect.

The risk usually associated with cookie dough is salmonella, a bacteria that can be found in raw eggs contained in the dough. Nestle’s cookie dough is packaged with labels warning consumers not to eat it raw. But people tend to disregard the warning – 39 percent of consumers eat raw cookie dough, according to Consumer Reports.