Washington Federal testing has failed to confirm green onions as the source of an outbreak of E. coli that sickened 64 people who ate in Taco Bell restaurants in the Northeast, health officials said Monday.
Over the weekend, Taco Bell officials said they determined that scallions were the likely source of the bacteria. But follow-up federal testing of those samples were negative for E. coli.
"In that context, we have not ruled out any food items," said Dr. David Acheson, chief medical officer for the FDA's Center for Food Safety and Applied Nutrition.
Meanwhile, health officials in New York said a sample of white onions taken from a Taco Bell restaurant tested positive for E. coli. However, that strain of bacteria hasn't been linked to any cases of illness in the United States anytime in the previous 30 days.
The positive sample initially was mistakenly identified as being green onion, Acheson said.
The Centers for Disease Control and Prevention has confirmed 64 E. coli cases in five states, most in New Jersey, New York and Pennsylvania plus two in Delaware and one in South Carolina. The South Carolina patient had eaten at a Pennsylvania Taco Bell.
Meanwhile, nearly three dozen people have fallen ill with symptoms consistent with E. coli infection after eating at a Taco John's restaurant in Cedar Falls, Iowa.
There is no indication the outbreaks are linked, but the CDC has not ruled out a connection, said Dr. Christopher Braden, a medical epidemiologist with the agency.
Iowa officials suspect a sick restaurant worker could have spread the illness. The two restaurant chains are not related.
It could take until midweek to determine whether the Taco Bell outbreak is over, Braden said. However, there have been no reports of anyone falling ill after Dec. 2, he added.