ATLANTA — The Centers for Disease Control and Prevention (CDC) announced on Oct. 22 that several agencies are investigating a multistate outbreak of E. coli O157:H7 linked to McDonald’s Quarter Pounder burgers.

CDC stated that at least 49 people have become sick in 10 states, with 10 people going to the hospital and one person dying. The agency said the one death was an older adult in Colorado.

The most current illnesses were reported in Colorado and Nebraska, but the CDC has seen cases in Iowa, Kansas, Missouri, Montana, Oregon, Utah, Wisconsin and Wyoming.

McDonald’s provided early information on the outbreak and its first action steps.

“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,” said Cesar Piña, chief supply chain officer of McDonald’s. “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 CDC explained that the preliminary traceback and distribution information reviewed by the US Food and Drug Administration (FDA) showed that slivered onions are a “likely source of contamination.”

“FDA is working quickly to confirm that these onions are a source of this outbreak and to determine if these onions were served or sold at other businesses,” the CDC stated. “FSIS is conducting traceback on hamburger patties served at McDonald’s to determine if ground beef is a source of illness.”

McDonald’s also announced it would temporarily remove the Quarter Pounder from restaurants in the impacted area, including Colorado, Kansas, Utah and Wyoming, as well as portions of Idaho, Iowa, Missouri, Montana, Nebraska, Nevada, New Mexico and Oklahoma.

“We take food safety extremely seriously, and it’s the right thing to do,” Pina said. “Impacted restaurants are receiving a stock recovery notice today and should reach out to their field supply chain manager or distribution center with any questions. We are working in close partnership with our suppliers to replenish supply for the Quarter Pounder in the coming weeks (timing will vary by local market).”

The company added that all other menu items, including beef products like the Cheeseburger, Hamburger, Big Mac, McDouble and Double Cheeseburger are unaffected and available.

The CDC reported that state and local public health officials continue to interview people about the food eaten in the week before becoming sick.

“Of the 18 people interviewed, all 18 (100%) report eating at McDonald’s, and 16 people report eating a beef hamburger,” the agency said. “Of 14 people who remember the specific beef hamburger they ate at McDonald’s, 12 (86%) report eating a Quarter Pounder hamburger.”