The Centers for Disease Control and Prevention and other federal agencies are investigating an E. coli outbreak linked to McDonald’s Quarter Pounders, sending McDonald’s stock down 7% in after-hours trading.

McDonald's Quarter Pounder hamburgers are being linked to an outbreak of E. coli that has sickened nearly 50 people in 10 states, killing one person, federal health officials said Tuesday. Most sick people reported eating Quarter Pounders from McDonald's,

Ten people have been hospitalized and one older person in Colorado has died after E. coli infections linked to McDonald's Quarter Pounder hamburger in 10 states, the U.S. Centers for Disease Control said on Tuesday.