Onions are likely source of E. coli outbreak linked to McDonald's, U.S. agencies say; 15 additional cases reported

An E. coli outbreak linked to McDonald's Quarter Pounders has led to dozens of illnesses in 13 states. (Mario Tama/Getty Images via CNN Newsource)

Fresh slivered onions served on McDonald’s Quarter Pounders were the likely source of an E. coli outbreak that has led to one death and illnesses in more than a dozen states, the U.S. Centers for Disease Control and Prevention and US Food and Drug Administration said Wednesday.

Additional cases associated with the outbreak have also been reported, bringing the total number of illnesses to 90 and hospitalizations to 27. However, the CDC notes that the current risk to the public is “very low,” as the reported illnesses happened before the affected onions were removed from food service locations.

“It is not necessary to avoid eating onions or other foods made with onions,” the CDC said.

Last week, supplier Taylor Farms issued a recall of four onion products due to “potential E. coli contamination.” McDonald’s stores in affected areas have temporarily stopped using slivered onions, and other fast food restaurants that received onions from this supplier – including Burger King, Taco Bell, Pizza Hut and KFC – have proactively removed fresh onions from their menus at some locations.

It is not likely that the recalled onions went to grocery stores or directly to consumers, the CDC said Wednesday. Diced onions used at McDonald’s have also not been linked to this outbreak, according to the FDA.

Beef patties used on Quarter Pounders were also part of the investigation, which started on October 22. But the Colorado Department of Agriculture said on Sunday that McDonald’s fresh beef patties used for the Quarter Pounder tested negative for E. coli, and the U.S. Department of Agriculture’s Food Safety and Inspection Service said on Monday that evidence did not point to ground beef as the probable source of the E. coli outbreak.

McDonald’s announced on Sunday that they would resume selling Quarter Pounders in all restaurants this week, but the 900 restaurants that had previously received slivered onions from Taylor Farms would not include onions on these sandwiches.