The always colorful and geographically precise, Bill Keene, senior epidemiologist with Oregon Public Health, told The Oregonian yesterday that mystery Mexican-style fast food chain restaurant A is Taco Bell.

"It’s been clear for weeks that Taco Bell was the source for many of the illnesses. It’s equally clear that it’s not all Taco Bell. It’s also not a single Taco Bell restaurant."

The first cases appeared at the beginning of April and continued through the third week in July. Dozens were sickened in Wisconsin, Indiana, Ohio and Kentucky, with a sprinkling of cases across the rest of the country. One person in Oregon — a woman in her 20s in Klamath County — got sick.

Keene said,

"It’s very striking to have two such similar outbreaks at roughly the same time and both of them affecting Taco Bell. The similarities might be a coincidence."

Although no one food or menu item has been named a culprit, Keene said epidemiologists think that lettuce, tomatoes or both were to blame.

"It’s not 100 percent sure it’s one or the other but those are the chief suspects," he said. "We’ve been unable to tease them apart because everyone eats both."

Keene said the food involved in the outbreaks was clearly contaminated before reaching Taco Bell franchises.

"It’s not something that they’re doing wrong. One of the products that they using in their food was contaminated."

The company did not return a phone call seeking comment.

CDC officials would not confirm that the company involved in the outbreaks was Taco Bell.

Naming a restaurant could have an economic impact on the company’s bottom line, said Kristen Nordlund, an agency spokeswoman.

The outbreak is also considered to be over though both the FDA and CDC are continuing to investigate.

"There’s no inherent reason for people to stop eating at Taco Bell now," Keene said.