Lettuce Suspected in Taco Bell E. Coli

People are seen as they dine at a Taco Bell restaurant in South Plainfield, N.J. Tuesday, Dec. 12, 2006. All but four of Taco Bell's 86 New Jersey restaurants were back in business Tuesday even as the fast-food chain and health officials across the country attempted to determine what caused an outbreak of E. coli that sickened scores of customers in four states. (AP Photo/Mel Evans) (Mel Evans - AP)

Acheson said no Taco Bell food samples, other than white onions from a New York restaurant, have tested positive for E. coli, Acheson said. The E. coli found in the white onion did not match the strain that sickened Taco Bell customers, however.

He said there is no evidence the Taco Bell outbreak is connected to cases of illnesses linked to Taco John restaurants in Iowa and Minnesota.

Health officials in those states said the cause of the outbreak _ which has sickened at least 50 people in Iowa and 27 in Minnesota _ has been tied to lettuce served at Taco John's in three cities.

Most E. coli infections are associated with undercooked meat, but increasingly produce is to blame. This fall, an outbreak linked to fresh spinach killed three people and sickened more than 200 others.

"This is a situation that is not tenable," Braden said.

Health officials believe most cases of E. coli contamination originate on the farm, where produce can come into contact with animal feces laden with the bacteria.

E. coli, or Escherichia coli, is a common and ordinarily harmless bacteria found in the guts of cattle and other animals. The E. coli O157:H7 strain can cause abdominal cramps, fever, bloody diarrhea, kidney failure, blindness, paralysis, even death.

On the Net:

CDC E. coli information: http://www.cdc.gov/ncidod/dbmd/diseaseinfo/escherichiacoli_g.htm