(UPDATED COVERAGE, Aug. 12) State health authorities claim vegetables served at Taco Bell restaurants may have caused a multistate salmonella outbreak from Kentucky to Oregon, but federal authorities have not established a link to any ingredient.

Rare types of salmonella caused illnesses in more than 150 people who dined at Irvine, Calif.-based Taco Bell Corp.’s locations in Ohio, Kentucky, Indiana, Wisconsin and Oregon during late June, when illnesses peaked.

UPDATED: Salmonella outbreak tied to Mexican-style fast food restaurant

Food and Drug Administration and
Centers for Disease Control investigators, however, aren’t pointing to any particular ingredients, restaurants and haven’t warned diners against eating certain foods or dining at particular restaurants.

“The extensive traceback effort was initiated to determine if a common source or supplier could be identified to help focus the epidemiologic investigations. No common food source was identified in either traceback,” the agency stated in an Aug. 4 news release.

Lola Russell, a CDC spokeswoman, said states handle foodborne illness investigations and that the CDC isn’t involved in identifying products or restaurants involved in recalls.

The FDA hasn’t made any call yet either.

In various media reports, Bill Keene, a senior epidemiologist with Oregon’s public health department, said scientists suspect lettuce and tomatoes singularly or together.

He said Taco Bell restaurants were the source for many of the illnesses, but said it was equally clear that the outbreak doesn’t involve all Taco Bell outlets and that the lettuce and tomatoes could have been contaminated before arriving at the restaurants.

The FDA and CDC didn’t name the restaurant, but said its analysis indicated the sicknesses after eating at a Mexican-style fast food restaurant chain.

The strains of salmonella involved in the sicknesses — Salmonella Hartford and Salmonella Baildon — seldom cause foodborne illnesses in the U.S.