FILE - This photo shows a McDonald's Quarter Pounder burger and fries in Times Square in New York on Oct. 23, 2024.

Quarter-pounder burgers will be back on the menu at hundreds of McDonald's after tests ruled out beef medallions as the source of an E. coli poisoning outbreak linked to the popular offering.

McDonald's announced Sunday that its quarter-pound burgers will be back on the menu at hundreds of its restaurants after tests ruled out beef medallions as the source of an E. coli poisoning outbreak linked to the popular burgers. which caused the death of one person and 75 others to become ill in 13 states of the United States.

The Food and Drug Administration (FDA) continues to believe that sliced ​​onions from a single supplier are the likely source of the contamination, McDonald's said in a statement. He said that next week he will resume selling quarter-pounder hamburgers at the affected restaurants, without the onions.

As of Friday, the outbreak had spread to at least 75 sick people in 13 states, federal health officials said. A total of 22 people had been hospitalized, and two developed a dangerous complication of kidney disease, the Centers for Disease Control and Prevention (CDC) reported. One person died in Colorado.

Initial information analyzed by the FDA showed that uncooked sliced ​​onions used in hamburgers “are a likely source of contamination,” the agency said. McDonald's has confirmed that Taylor Farms, a California-based produce company, was the supplier of the fresh onions used at the restaurants involved in the outbreak, and that they came from a facility in Colorado Springs, Colorado.

McDonald's pulled its Quarter Pounder burger from menus in several states — most of them in the Midwest and Rocky Mountains — when the outbreak was announced Tuesday. The company said Friday that sliced ​​onions from the Colorado Springs facility were distributed to approximately 900 of its restaurants, including some located in transportation hubs such as airports.

The company reported that on Tuesday it removed sliced ​​onions from those facilities from its supply chain, and indicated that it has decided to stop purchasing onions from the Taylor Farms facility in Colorado Springs “indefinitely.”

The 900 McDonald's restaurants that used to receive sliced ​​onions from the Taylor Farms facility in Colorado Springs will resume sales of Quarter Pounders without sliced ​​onions, McDonald's said.

Testing by the Colorado Department of Agriculture ruled out beef medallions as the source of the outbreak, the company added.

The Department of Agriculture received many batches of fresh and frozen beef medallions collected from several McDonald's restaurants in Colorado linked to the E. coli investigation. All samples tested negative for that bacteria, the department said.

Taylor Farms said Friday that it had recalled yellow onions shipped to customers from its Colorado facility out of an abundance of caution, and is continuing to work with the CDC and FDA as they investigate.

Most of the illness cases reported as of Friday had occurred in Colorado, with 26. At least 13 people were sickened in Montana, 11 in Nebraska, 5 in New Mexico and the same number in Utah, 4 in Missouri and the same number in Wyoming, two in Michigan and one in each of the following states: Iowa, Kansas, Oregon, Wisconsin and Washington, the CDC reported.