Iceberg Lettuce Seen as Taco Bell

THURSDAY, Dec. 14 (HealthDay News) -- U.S. health officials late Thursday declared theE. colioutbreak linked to Taco Bell restaurants in the Northeast to be over, even as the investigation into suspect lettuce continued.

In their declaration, officials at the U.S. Centers for Disease Control and Prevention also said, "Based on a number of factors, iceberg lettuce is considered overall to be the single most likely source of the outbreak at this time."

Tests on green onions, initially thought to be the cause of the bacterial outbreak that sickened at least 71 people in five states, had proven negative, health officials said earlier.

"We have identified several ingredients that may be associated with the outbreak. These include lettuce, ground beef and cheddar cheese," Dr. Christopher Braden, a medical epidemiologist at the U.S. Centers for Disease Control and Prevention, said during a teleconference late Wednesday. "The most likely food vehicle is lettuce. But we are still looking at other food items."

Dr. David Acheson, chief medical officer at the U.S. Food and Drug Administration's Center for Food Safety and Applied Nutrition, said it was too early to speculate where the lettuce -- if it is proven to be the source of the contamination -- was grown.

"To date, no food samples have come up withE. colithat matches the outbreak," Acheson said. "The primary focus is on lettuce, but we are also looking at cheese."

The FDA hopes to trace the lettuce to its source, but officials conceded that could be tough because the lettuce was shredded and processed in bulk.

Taco Bell said after the news conference that a CDC analysis showed a "statistical probability" that lettuce was the source of contamination, after the agency conducted interviews with those who have become ill. Lettuce is served in approximately 70 percent of all Taco Bell menu items. The lettuce supplied to Taco Bell restaurants in New York, New Jersey, Pennsylvania and Delaware was grown by various farmers and shipped to the company's former produce supplier, the company said in a prepared statement.

The outbreak also appears to be winding down, the FDA officials added, although there are people who still may be confirmed with the illness in coming days.

"These numbers may increase in the next few days. However, we are seeing a decline in cases," Braden said.

Acheson added that there was "no indication that the Taco Bell outbreak has anything to do with the Taco JohnE. colioutbreak in Minnesota and Iowa."

Almost three dozen people have fallen ill in recent days with symptoms consistent withE. coliinfection after eating at a Taco John's restaurant in Cedar Falls, Iowa.