Slivered onions served on McDonald’s items including Quarter Pounder hamburgers were the likely source of an E. coli outbreak that has sickened at least 90 people in the U.S., the Centers for Disease Control and Prevention said on Wednesday.
The outbreak was first reported on Oct. 22.
The U.S. Food and Drug Administration and the company have confirmed that Taylor Farms was the supplier for the affected locations, and it has since recalled several batches of yellow onions produced in a Colorado facility.
The CDC said the number of infected people has risen, from 75 to 90. Twenty-seven people have been hospitalized due to the illness, which has already killed one person.
As of Oct. 24, two people had developed hemolytic uremic syndrome, a serious condition that can cause kidney failure.
The E. coli O157:H7 strain that led to the McDonald’s outbreak is said to cause “very serious disease,” especially for the elderly, children and people who are immunocompromised.
The FDA noted that symptoms begin anywhere from a few days after consuming contaminated food to up to nine days later.
WATCH | Slivered onions pulled due to E. coli outbreak at McDonald’s:
One person has died and dozens more are ill after eating at various McDonald’s restaurants across the United States. Colorado leads the 10 states reporting illnesses in the number of cases, and the U.S. Centers for Disease Control is investigating the onions used in the Quarter Pounder hamburgers as the potential source of the bacteria, while the beef patties remain another suspect.
As of Oct. 30, the outbreak had affected people in Colorado, Kansas, Utah, Wyoming, Iowa, Missouri, Montana, Nebraska, New Mexico, Oregon, Wisconsin, Washington and Michigan. McDonald’s Canada said it has not been not impacted in any way.
Colorado has reported the highest infections with 29 people who have fallen sick, while Montana reported 17 infections.
McDonald’s said that it would resume selling Quarter Pounder burgers this week after it temporarily took the item off the menu in a fifth of its 14,000 U.S. restaurants.
Chris Kempczinski, CEO and president of McDonald’s, apologized for the outbreak on Tuesday on a conference call with investors.
“Nothing is more important to us than the safety of our customers,” Kempczinksi said. “The recent spate of E. coli cases is deeply concerning, and hearing reports of how this has impacted our customers has been wrenching for us.”
