• Fast food chains are pulling onions from their restaurants due to the risk of E. coli.
• Taco Bell, KFC and Johnny Rockets joined McDonald's in withdrawing the ingredient from some locations.
• The McDonald's-related outbreak includes 49 E. coli cases and one death in 10 states.

A number of American fast food chains and restaurants are withdrawing fresh onions from some of their stores due to the risk of food poisoning from E. Coli.

Yum Brands, the parent company of Taco Bell, Pizza Hut and KFC, said it was withdrawing the ingredient from some restaurants out of an abundance of caution, the company told Bloomberg on Thursday. Yum did not disclose the number or location of restaurants or specific suppliers.

On Thursday, Burger King said it was sourcing some of its onions from Taylor Farms, a supplier to the McDonald's restaurants linked to the E. coli outbreak.

Burger King said there had been no cases of illness or that authorities had been contacted to ask whether the company was affected. But it ordered outlets that received the onions – 5% of about 7,000 outlets – to immediately discard the vegetable.

Fat Brands, which owns Johnny Rockets and other restaurants, also announced Thursday that it had stopped using Taylor Farm onions.

Burger King, Yum Brands and Fat Brands did not respond to a request for comment sent after hours.

The series of withdrawals comes after 49 cases of E. coli infections and one death in a food poisoning outbreak in 10 states. The Centers for Disease Control and Prevention said Tuesday that anyone who developed severe E. coli symptoms after eating a McDonald's should do so Quarter Pounder should call their healthcare provider.

Public health officials are investigating which ingredient may be causing the outbreak. Initial information from the FDA suggests that the onion slices or beef patties used in Quarter Pounders are the likely source of the contamination.

McDonald's has temporarily removed the Quarter Pounder from its menus in Colorado, Kansas, Utah and Wyoming, as well as parts of surrounding states.

Other restaurants have had similar food safety issues in recent years.

Outbreaks at Mexican fast-casual chain Chipotle cost the company $25 million to resolve criminal charges related to outbreaks that affected 1,100 people between 2015 and 2018. The company announced a series of new food safety protocols in 2016 and its shares eventually recovered.

In 2022, Wendy's restaurants have been linked to an E. coli outbreak in six states.

Both outbreaks involved hundreds of cases, far more than the number of people currently known to be affected by the current McDonald's-related outbreak.

McDonald's stock price is down over 4% this week as news of the outbreak spreads and investors fear the cases will impact sales of the Quarter Pounder.