Federal health officials said Wednesday that lettuce is the most likely source of the E. coli outbreak linked to Taco Bell restaurants in the Northeast.
Although investigators have not finished testing, they are calling shredded lettuce the "most likely" culprit.
"We think that shredded lettuce consumed at Taco Bell restaurants was the most likely cause of the outbreak," says Center for Disease Control and Prevention epidemiologist Dr. Christopher Braden in a telephone news conference, but cautions that "we're not done with the investigation."
Investigators compared the ingredients that had been consumed by both sickened and healthy individuals who had eaten at suspected Taco Bells in the Northeast, narrowing down the most likely sources to lettuce, beef, and cheddar cheese. Since beef is cooked and cheese is pasteurized, lettuce emerged as the most likely candidate.
Citing test results from an independently hired laboratory, Taco Bell had blamed green onions for the outbreak and removed scallions from all 5,800 of their U.S. restaurants - but government follow-up testing of the same green onion samples showed no evidence of E. coli, and the CDC said on Tuesday that onions were probably not the source of the outbreak.