Taco Bell lettuce suspected in E.coli outbreak

(REUTERS) -- An ingredient used in 70 percent of Taco Bell's products, lettuce, probably caused an E.coli outbreak that sickened dozens of people in the U.S. Northeast, food safety officials said on Wednesday.

The Mexican-style chain, a unit of Yum Brands (Charts), said it had taken appropriate steps to make sure its food was safe by switching produce suppliers and added that it was leaving lettuce on its menu.

"It's not necessary for us to remove lettuce," Taco Bell President Greg Creed said on a conference call with reporters.

A total of 71 people have fallen sick because of the E. coli outbreak linked to Taco Bell, the officials said, but no new cases have been reported since Dec. 6.

U.S. health officials said in a conference call before Taco Bell's that lettuce became the focus of the investigation after a statistical analysis of what people had eaten before they fell ill. Many also ate cheddar cheese and beef, and those supply chains are also being investigated, officials said.

"It would be folly at this point to drop the cheese completely. It's critical to keep all options open," said David Acheson, Chief Medical Officer of the FDA's Center for Food Safety and Applied Nutrition. Creed said health officials had told the chain that cheese and beef were unlikely to have caused the outbreak because the cheese is pasteurized and because of the way the beef is prepared.

But none of the other ingredients used at Taco Bell appeared to be associated with the outbreak, Acheson said adding no ingredients have tested positive for the E.coli strain blamed for the outbreak. "The fact that the testing is negative does not put me off," he said.

Neither Taco Bell nor the FDA would disclose the name of the company that supplied the lettuce to Taco Bell restaurants in New Jersey, New York, Pennsylvania and Delaware. Taco Bell said that at certain points during the outbreak 90 restaurants were closed.

Creed said only that the lettuce was grown in the Western United States and that Taco Bell buys less than 20 percent of the lettuce produced by the supplier in question. Before lettuce arrives at Taco Bell restaurants, it is rinsed multiple times, shredded and packed in sealed containers, Creed said. It is not rinsed at the restaurants.

Last week, Taco Bell banned green onions after an earlier test, since discredited, showed they may have been the source of contamination. The company has no plans to put green onions back on the menu.

"We just don't want to take any chances at this time," Creed said. Food safety officials said restaurants appeared to be safe. "We are fairly confident that the contaminated product is not being distributed or served at this point," said Christopher Braden, Medical Epidemiologist at the Centers for Disease Control and Prevention. Braden conducted the statistical study.

Health officials also said that the Taco Bell outbreak was not believed to be related to E.coli infections in Minnesota and Iowa that have been linked to Taco John's restaurants.

To help analyze its food safety practices, Creed said the company hired food safety expert Mike Doyle of the University of Georgia, who informed the company that its standards "are some of the highest in the industry." The company has not changed those standards in response to the outbreak, he said.