Onions probably didn't cause the E. coli outbreak linked to Taco Bell, the Centers for Disease Control and Prevention said, as the fast-food chain launched a media campaign to persuade customers its food is safe.
Its analysis had shown so far that "onions of any type are probably not linked to this outbreak," the CDC said Tuesday.
The announcement came one day after the U.S. Food and Drug Administration said it could not confirm that scallions were the cause of the problem, as previously suspected, and that it was not ruling out any food as a possible culprit.
The statements could complicate Taco Bell's efforts to reassure patrons through a wide-reaching media blitz.
In an open letter to customers published in USA Today, The New York Times and other newspapers, Taco Bell President Greg Creed said he would support the creation of a coalition of food suppliers, competitors, government and other experts to explore ways to safeguard the food supply chain and public health.
Creed underscored the safety mantra in media interviews, telling Associated Press Television that he had assured his daughter, a college freshman in New York, and her friends that Taco Bell food is safe.
"I can assure you, I would not tell my daughter that unless I absolutely believed it," Creed said.
Creed did not provided further details about how an industry safety coalition might work. Representatives of other fast-food chains did not immediately return calls seeking comment.
Bryan Silbermann, president of the Produce Marketing Association, a trade group that represents restaurants, farmers and other companies in the produce supply chain, said such an industry coalition already exists.
The group was formed two years ago and has been particularly active since September, when three people died and more than 200 became ill because of a spinach-related E. coli outbreak.
"The largest restaurant and supermarket chains have been active in this process," Silbermann said. "As far as I'm aware, Taco Bell has not been involved."
Irvine-based Taco Bell, a subsidiary of Louisville, Ky.-based Yum! Brands ran ads in a number of papers in New Jersey, New York, Pennsylvania and Delaware, where an outbreak of the bacteria has sickened 67 people who ate at the chain's restaurants.
A sample of white onions taken from a Taco Bell restaurant in New York was found to be positive for a strain of the bacteria that hasn't been linked to any cases of illnesses in the U.S. within 30 days, the FDA said.
Taco Bell spokesman Rob Poetsch said the company believes its food is safe because green onions were removed from use last week and restaurants have been sanitized. No additional cases of Taco Bell patrons falling ill with E. coli have been reported since Dec. 2, according to the FDA.
Some Taco Bell regulars weren't worried.
"Even if they don't know what caused the outbreak, Taco Bell restaurants are probably safer now than before because of all the scrutiny they've received," said Bruce Brandywine, 41, who was one of eight people in line at lunchtime at the Taco Bell in DeWitt, a suburb of Syracuse, N.Y.
Separately, nearly three dozen people were sickened in recent days with symptoms consistent with E. coli infection after eating at a Taco John's restaurant in Cedar Falls, Iowa.
Authorities are also investigating reports that several other people became ill after eating at one of the chain's restaurants in Albert Lea, Minn.
On Tuesday, several lawmakers, including Sens. Charles Schumer and Hillary Rodham Clinton, both Democrats from New York, called on federal agencies create a joint task force to examine the E. coli outbreak and recommend changes in laws and regulations to prevent contamination of food.
After being harvested, most produce is moved to processing plants where it is washed, sorted and cooled for transport to supermarkets or distribution centers around the country.
Major distributors follow testing guidelines at various steps along the chain. For the past decade, all the major restaurant and supermarket chains have insisted that outside auditors monitor suppliers, Silbermann said.
Jim Lugg, food safety chief at Salinas, Calif.-based produce processor and distributor Fresh Express, said the company has standards in place that cover the entire supply chain.