Health officials are investigating E. coli outbreak linked to McDonald’s Quarter Pounders in multiple states, the Centers for Disease Control and Prevention said Thursday.
It’s not yet known which ingredient in the hamburgers is making people sick. Slivered onions and quarter-pound beef patties, both of which are specifically used for Quarter Pounders, are being looked at.
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 working with public health officials, according to the CDC. The fast-food chain has stopped using the slivered onions and quarter-pound beef patties in several states, the CDC said.
McDonald’s released a statement Tuesday afternoon, saying that its “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.”
“We will 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.
“This is a fast-moving outbreak,” Matt Wise, chief of the CDC’s Outbreak Response and Prevention Branch, told NBC News.
The first case occurred on Sept. 27. State health officials in Colorado alerted the CDC of an unusual uptick in E. coli cases on Oct. 10, Wisely told NBC News. The agency started its investigation on Oct. 15.
While the overall risk to the public is low now that McDonald’s has pulled Quarter Pounders from its restaurants in affected states, Wise said he suspects more illnesses may be reported.
The CDC said that recent illnesses may not have been reported yet as “it usually takes 3 to 4 weeks to determine if a sick person is part of an outbreak.”
Symptoms of E. coli infection include high fever over 102 degrees, severe stomach cramps, diarrhea and vomiting.
Sixteen of the people who were sickened said they’d eaten at McDonald’s before they got sick, Wise said. Twelve of those people specifically said they’d had a Quarter Pounder hamburger.
The Food and Drug Administration said that it’s “working quickly to confirm” whether the slivered onions were served or sold to other businesses.
Diced onions used in other products at McDonald’s are not implicated in the outbreak, the FDA said.
The Department of Agriculture is also assisting the CDC and state health officials in the investigation.
Most of the cases, 27, have been reported in Colorado. Nebraska has reported nine patients.
Other cases are in Iowa, Kansas, Missouri, Montana, Oregon, Utah, Wisconsin and Wyoming.