Though the CDC has not targeted a particular food source as the cause of the outbreak, Taco Bell officials announced that the restaurant chain would no longer serve green onions -- thought to be the most likely source of the bacteria -- in any of its 5,800 nationwide restaurants.
Taco Bell officials said in a statement that green onions were the only ingredient to test positive for E. coli in independent tests of more than 150 samples of the fast food chain's ingredients from several states.
However, an opened bag of white onions at a Taco Bell in Hempstead, NY, tested positive for E. coli yesterday, according to New York Health Department spokesman Marc Carey. Because the bag was open, that contamination was thought to be an isolated incident, Carey said.
Escherichia coli bacterial infections are generally caused by consuming undercooked meat that has been in contact with animal feces. However, E. coli can also infect leafy vegetables such as lettuce and spinach.
Those infected with certain strains of E. coli can experience fever, abdominal cramps, kidney failure, blindness, bloody diarrhea, paralysis or even death.
A separate outbreak of E. coli was reported last week in Iowa, where roughly 40 people have reported symptoms consistent with the bacteria. Fourteen people have been hospitalized and are awaiting tests to confirm their illnesses.
The Associated Press reported the people fell ill after eating at a Taco John's restaurant in Cedar Falls. Paul Fisherkeller -- Taco John's president and CEO -- said all food from that restaurant had been removed and replaced with different food as a precaution.
Taco Bell restaurants -- owned by Yum Brands -- announced it has closed, sanitized and re-stocked affected restaurants, and has changed produce suppliers for its Northeast chains.