FDA: Lettuce, Not Green Onions, Probable Source of E. Coli

27/12/06 The Food and Drug Administration (FDA) has narrowed its investigation of an outbreak of E. coli O157:H7 infections linked to Taco Bell restaurants in Northeastern states by focusing its efforts on finding the sources of shredded lettuce served at the stores.

This new focus is based on the fact that three items -- shredded lettuce, cheddar cheese and cooked ground beef -- were implicated in a study conducted by the U.S. Centers of Disease Control and Prevention (CDC) as the items most likely to have been the vehicles of pathogen (disease-causing agent) transmission in this outbreak. Based on a number of other factors, as well as food processing techniques used for cheese (pasteurization) and ground beef (cooking), lettuce is considered overall to be the single most likely source of the outbreak at this time.

The information about items likely to have transmitted the pathogen in this outbreak comes from a CDC "case control" study, which involves interviewing ill and well Taco Bell restaurant patrons about what food items they consumed. By comparing foods consumed by ill and well persons, investigators can show statistical links to particular food ingredients. According to the FDA, this does not establish that these foods are the causes of the outbreak, but it does give clues as to where further investigation should focus to try to find hard evidence of the cause.

Because of this, FDA investigators are further expediting review of Taco Bell records obtained from the firm in order to trace the distribution channels of the lettuce and identify the farm or farms where the lettuce was grown, as well as all firms and facilities that handled the product between harvest and delivery.

FDA has no indication that lettuce or cheese served at any other restaurant, or lettuce or cheese sold in any other venue, is connected with this outbreak. The agency is aware of the outbreaks of E. coli O157:H7 at Taco John's restaurants in Iowa and Minnesota, and is monitoring these closely in cooperation with state health authorities. Based on available information these outbreaks do not appear at this time to be related to the Taco Bell outbreak.