McDonald's (MCD) shares tumbled over 6% in premarket trading on Wednesday after the Centers for Disease Control and Prevention said the company's quarter pounder burgers had been linked to an E. coli outbreak in some states, with most illnesses in Colorado and Nebraska.
"This is a fast-moving outbreak investigation," the CDC wrote on its website. "Most sick people are reporting eating Quarter Pounder hamburgers from McDonald’s and investigators are working quickly to confirm which food ingredient is contaminated."
The company's stock had sunk as much as 10% in extended trading in the immediate aftermath of the news on Tuesday.
The CDC said McDonald’s has stopped using fresh slivered onions and quarter-pound beef patties in certain states while a source of the illness is confirmed.
One person has died from the outbreak, the agency said, and 10 hospitalizations have been reported across 10 states.
In an internal memo McDonald's shared on its website Tuesday evening, McDonald's chief supply chain officer of North America Cesar Piña said the company is taking "swift and decisive action" and noted that the initial findings from the investigation "indicate that a subset of illnesses may be linked to slivered onions used in the Quarter Pounder and sourced by a single supplier that serves three distribution centers."
"As a result, and in line with our safety protocols, all local restaurants have been instructed to remove this product from their supply and we have paused the distribution of all slivered onions in the impacted area," the company said.
It will be temporarily removing the menu item from restaurants in the impacted areas, including Colorado, Kansas, Utah and Wyoming, as well as portions of Idaho, Iowa, Missouri, Montana, Nebraska, Nevada, New Mexico, and Oklahoma. All other menu items are available.
Fellow fast-food giant Chipotle (CMG) went through its own E. coli outbreak in 2015, along with an outbreak of the norovirus. The company was forced to temporarily close 43 locations in Washington and Oregon as a result.
The CDC declared the outbreak over in February 2016, with the company undergoing an aggressive revamp of its food preparation methods.
But it took years for the Mexican fast-food giant to rebuild brand trust and recover its stock price as a result of the crisis. Shares are up more than 500% since 2016.
