The number of E. coli cases linked to McDonald’s Quarter Pounders has risen to 90, the Centers for Disease Control and Prevention said Wednesday, up from 75 reported cases last Friday.
The slivered onions used on the burgers are the “likely source” of the outbreak, the CDC said.
A spokesperson for McDonald’s said that all Quarter Pounders in affected states had been pulled from the restaurants by Oct. 22, when the outbreak was first announced.
The CDC said that any further risk to the public is “very low.” The most recent case was on Oct. 16.
On Sunday, Colorado Agriculture Department officials ruled out the beef patties used in the Quarter Pounders as the outbreak’s source after testing found no traces of E. coli.
One person has died in the outbreak, and 27 have been hospitalized so far, the CDC said. At least two people developed a rare kidney illness called hemolytic uremic syndrome.