According to the Center for Disease Control, externalthe dates of onset of the disease in humans vary from September 12 to October 21.
Onions have been directly introduced into many western and midwestern states, including Colorado, Iowa, and Kansas. Other areas such as Oklahoma, Idaho and New Mexico were also affected.
Onion and environmental samples from McDonald’s stores and distribution centers were collected by the FDA, the Colorado Department of Agriculture, and the Colorado Department of Health and Environment.
Of those who got sick, four people developed hemolytic uremic syndrome (HUS), a rare kidney disease that can damage red blood cells.
The federal agency said tests on samples are continuing, adding that it has completed on-site inspections at an onion plant in Washington state and a Taylor Farms processing facility in Colorado.
In an update to the FDA, health officials said they are continuing to work with food suppliers and their customers.
“At this time, there does not appear to be an ongoing food safety concern related to this outbreak at McDonald’s restaurants,” the update said.
He added that it was “unlikely” that the recalled onions were “sold in grocery stores or directly to consumers.”