While its investigation remains active, the Food and Drug Administration said in a Nov. 13 press release that onion samples collected so far are inconclusive, and additional testing is being conducted to conclusively identify the source of a deadly E. coli 0157:H7 outbreak in 14 states.
The number of samples taken as of Nov. 13 was not specified, but the latest news release that one sample did test positive for E. coli, but it was a “non-toxin producing” strain and not a match for the strain that sickened 104 people, with one death attributed to the food-borne illness.
More testing is underway, the FDA said. The outbreak is said to have originated at McDonald’s restaurants in several states, and first cases were reported in late September. Taylor Farms was identified as the supplier of onions, with a processing facility in Colorado Springs, CO, named as the source of slivered onions being investigated.
Taylor Farms processing facility and a Washington grower have been inspected, but results of those inspections had not been made public as of Nov. 13.
The agency release said, “FDA, CDC, and state partners continue investigating a multistate outbreak of E. coli O157:H7 linked to slivered onions served on Quarter Pounder burgers at McDonald’s restaurants in certain states. As of November 13, 2024, 104 people infected with the outbreak strain of E. coli O157:H7 have been reported from 14 states. Of 98 people with information available, 34 have been hospitalized, and 4 people developed HUS, a serious condition that can cause kidney failure. One death has been reported from an older adult in Colorado. This person is not one of those who developed HUS. Of the 81 people interviewed, 80 (99%) report eating at McDonald’s. Seventy-five people were able to remember specific menu items they ate at McDonald’s. 63 of 75 people (84%) reported a menu item containing fresh slivered onions.
“FDA, Colorado Department of Agriculture (CDA), and Colorado Department of Public Health and Environment (CDPHE) have collected onion and environmental samples from McDonald’s stores, distribution centers, and firms of interest for laboratory analysis. At this time, one FDA sample of recalled onions has tested positive for E. coli, but it is a non-O157:H7 Shiga toxin-producing E. coli (STEC) and does not match the outbreak strain or any other clinical illnesses. Whole genome sequencing (WGS) analysis determined that the sample is positive for E. coli O168:H8 and contains the Shiga toxin gene stx2a. Additional sample this time, one FDA sample of recalled onions has tested positive for E. coli, but it is a non-O157:H7 Shiga toxin-producing E. coli (STEC) and does not match the outbreak strain results are pending. More information will be provided in this update as it becomes available.
“FDA has completed onsite inspections at a Taylor Farms processing center in Colorado and an onion grower of interest in Washington state.
“McDonald’s stopped using slivered onions on Quarter Pounder burgers in affected states, and Taylor Farms recalled yellow onions on October 22, 2024. Food service customers were notified by Taylor Farms that they should not sell or serve recalled yellow onions. FDA continues working with Taylor Farms and their direct customers to determine if additional downstream customer recalls are necessary. Food service customers should not be further distributing recalled onions. According to available information, recalled onions should not be available for purchase in grocery stores. McDonald’s has reintroduced slivered onions from a different onion supplier into their full menu. At this time, there does not appear to be a continued food safety concern related to this outbreak at McDonald’s restaurants.” Read the full update
