The Food and Drug Administration, the Centers for Disease Control and Prevention and the Colorado Department of Public Health are continuing with their investigation of the extensive outbreak of E.coli O157:H7 attributed to onions served with McDonald’s Quarter Pounder sandwiches. As of mid-November, 104 diagnosed cases have been recorded from fourteen states with 34 hospitalizations including four cases of HUS and one fatality.
Enigmatically, the Colorado Department of Agriculture in collaboration with the Colorado Department of Public Health and Environment have failed to demonstrate the outbreak strain in the Taylor Farms processing center. E.coli O168:H8 with a Shiga toxin gene stx2a was identified although additional samples are undergoing whole genome sequencing.
McDonald’s switched the supplier of onions and has resumed adding the ingredient to Quarter Pounder sandwiches, resulting in resumption of halitosis.
The earlier food safety concern has obviously abated.