CDC says 90 people affected in E. coli outbreak linked to McDonald’s Quarter Pounders

Ninety people in 13 states have been infected in a deadly E. coli outbreak linked to McDonald's Quarter Pounders, the Centers for Disease Control and Prevention said Wednesday, as it continues to investigate the source of the spread.

The outbreak has led to 27 hospitalizations and one previously reported death of an older adult in Colorado. 

Before Wednesday, the CDC last gave an update on the outbreak on Friday, when the agency said it had 75 cases in 13 states. The agency first announced the outbreak on Oct. 22.

Fresh slivered onions served on Quarter Pounders and other menu items at McDonald's are "the likely source of this outbreak," the CDC said on its website on Wednesday.

The additional illnesses are from before McDonald's and Taylor Farms, which supplied onions to the affected region, took action to remove the ingredient from affected locations, the agency added. The CDC believes the risk to the public is "very low" due to the efforts from McDonald's and Taylor Farms. 

"The likelihood of contaminated onions still being available for sale is low," the agency wrote. 

Quarter Pounder hamburgers are a core menu item for McDonald's, raking in billions of dollars each year. The fast-food giant on Sunday said the burgers will return to roughly a fifth of U.S. restaurants this week, or about 3,000 locations, after it pulled the menu item due to the outbreak. 

But around 900 of those locations will serve the Quarter Pounder without slivered onions for the foreseeable future as the CDC and other health authorities continue to examine the source of the outbreak. The change will affect restaurants in Colorado, Kansas and Wyoming as well as parts of Idaho, Iowa, Missouri, Montana, Nebraska, Nevada, New Mexico, Oklahoma and Utah.