Health officials appear to have located the source of five dozen E. coli O157 illnesses linked to the Fond du Lac Reservation, in Minnesota, in July. Minnesota Department of Health (MDH) spokesman Doug Schultz says that the trace-back investigation has led investigators to three events in mid-July, between the 11th and 16th, including an Elders’ Picnic, a wedding celebration, and a three-day conference. The same caterer supplied food to all three events, including potato salad to two of the events, and ingredients served in potato salad to the third event. “After interviewing a good percentage of the people involved,” Schultz told local reporters, “there are clear indications that the potato salad was the likely vehicle for the illness.” Because potato salad was not provided to patrons of the third event, the MDH believes that celery or onions may be the ingredient in the potato salad that caused all of the illnesses. Schultz stated, however, in product testing “we were unable to find any pathogens on the celery we tested.” Unfortunately, current product testing is unable to determine if celery that was consumed in July was tainted with E. coli O157.

The 60 identified victims all were sickened in the days following exposure between July 11 and 16, and with the most recent victim presenting on July 20th, MDH officials feel confident the outbreak is over. E. coli lawyer Ron Simon confirmed this assessment, but all stated “this does not mean that all of the victims have been properly identified.” Simon explained that most victims of an outbreak are not properly tested and reported, and so the actual number of victims is likely much higher.

MDH’s Schultz also told local reporters that health officials have conducted a thorough investigation of the caterer and so far have not yet found any “red flags” or signs of “cross contamination,” but at the same time admitted that contamination may have occurred off-premise. While not ruling out a “smoking gun,” Schultz conceded that we may never know exactly how the ingredients in the potato salad were contaminated with E. coli in the first place.

The E. coli lawyers at Ron Simon & Associates are investigating the outbreak and are currently interviewing victims.