Health officials are investigating an E. coli outbreak linked to McDonald’s Quarter Pounders in multiple states, the Centers for Disease Control and Prevention said Tuesday.
It is not yet known which ingredient in the burgers is making people sick. The focus is on chopped onions and quarter-pound beef patties, both of which are specifically used in Quarter Pounders.
At least 49 people in 10 states have been sickened. One person, an older adult in Colorado, has died.
Ten people have been hospitalized, including a child who developed a kidney disease called hemolytic uremic syndrome.
McDonald’s is cooperating with public health officials, according to the CDC. The fast-food chain has stopped using the chopped onions and quarter-pound beef patties in several states, the CDC said.
McDonald’s said in a statement Tuesday afternoon that “initial findings from the investigation indicate that a subset of illnesses may be linked to sliced onions used in the Quarter Pounder, which originated from a single supplier serving three distribution centers.”
“We continue to work with the Centers for Disease Control and Prevention (CDC) and are committed to providing timely updates as we restore our full menu,” the statement said.
Matt Wise, chief of the CDC’s Outbreak Response and Prevention Branch, told NBC News: “This is a fast-moving outbreak.”
The first case occurred on Sept. 27. Colorado health officials alerted the CDC to an unusual increase in E. coli cases on Oct. 10, Wise said. The agency launched its investigation on Oct. 15.
While the overall risk to the public is now low, now that McDonald’s has removed Quarter Pounders from its restaurants in the affected states, Wise said he suspects more illnesses could be reported.
The CDC said recent illnesses may not have been reported yet because “it usually takes 3 to 4 weeks to determine whether an ill person is part of an outbreak.”
Symptoms of an E. coli infection include a high fever of more than 102 degrees, severe stomach cramps, diarrhea and vomiting.
Sixteen of the people who got sick said they had eaten at McDonald’s before they got sick, Wise said. Twelve of those people specifically said they had eaten Quarter Pounder burgers.
The Food and Drug Administration said it is “working quickly to confirm” whether the sliced onions were served or sold to other companies.
Sliced onions used in other products at McDonald’s are not involved in the outbreak, the FDA said.
The Department of Agriculture is also helping the CDC and state health officials with the investigation.
The majority of the cases, 26, have been reported in Colorado. Nebraska has reported nine.
Other cases are in Iowa, Kansas, Missouri, Montana, Oregon, Utah, Wisconsin and Wyoming.
CORRECTION: (Oct. 22, 2024, 10:24 p.m. ET) An earlier version of this article misstated the number of E. coli cases in Colorado, based on CDC reporting. According to the Colorado Department of health
, there are 26 cases, not 27.