Outbreak of E coli 0157 illness linked to Taco Bell restaurants

For a while there last month, it looked like green onions would go the way of bagged spinach, lettuce, and carrots: all of them contaminated with disease-causing bacteria, all of them temporarily (or permanently) off limits for consumption. But by the time the uproar began to die down, green onions were off the hook and shredded lettuce was proclaimed the most likely culprit in the last month's outbreak of E coli 0157 linked to eating at Taco Bell restaurants ( http://www.cdc.gov/).

To backtrack, an outbreak of dangerous E coli 0157 infection in New Jersey was initially traced to a Taco Bell restaurant. Then new cases popped up in patrons who had eaten at Taco Bell outlets in the adjoining states of New York, Pennsylvania, and Delaware. Numbers of affected cases as high as 200 were reported in the press, some Taco Bell outlets closed down, and a triumph of epidemiologic sleuthing was proclaimed when Taco Bell announced they had found the bacterium in a half-empty bag of green onions. So Taco Bell stopped using green onions as an ingredient, scrubbed down their restaurants, and proclaimed all was well.

Alas, it wasn't that simple. Further testing by the Centers for Disease Control (CDC) established that the reported test was faulty and that the E coli 0157 strain associated with Taco Bell outlets had not been found in samples of green (or white) onions used at the restaurants. By mid-December, according to the CDC, 71 cases of infection with the E coli 0157 strain associated with the Taco Bell outbreak had been reported: 33 in New Jersey, 22 in New York, 13 in Pennsylvania, two in Delaware, and one person in South Carolina who had eaten in a Taco Bell in Pennsylvania. Among these cases, 53 were hospitalized and eight developed hemolytic uremic syndrome (HUS). Numbers of new cases had declined substantially by then, and the outbreak appeared to be winding down. The CDC and the US Food and Drug Administration (FDA) are on the case, trying to make a definitive identification of the contaminated ingredient, find out how the contamination occurred, and rectify the situation.