McDonald’s Stock Tumbles as US Investigates Quarter Pounder’s Link to E. Coli Outbreak

Shares of McDonald’s (MCD) plummeted in extended trading Tuesday after U.S. health authorities said they were investigating an E. coli outbreak possibly linked to the burger chain’s Quarter Pounder. 

The Centers for Disease Control and Prevention (CDC) said in a statement Tuesday that 49 cases of E. coli infection had been reported across 10 states. Ten known cases have resulted in hospitalization and 1 death has been reported. 

“Most people in this outbreak are reporting eating the Quarter Pounder hamburger at McDonald’s before becoming sick. It is not yet known which specific food ingredient is contaminated,” the agency said. 

Regulators said McDonald’s was collaborating with their investigation, and had stopped offering shaved onions and quarter-pound hamburger patties in several states. Cases have been concentrated in Colorado and Nebraska, according to the CDC. 

McDonald’s shares fell more than 9% to $286.27 in after-hours trading Tuesday.