In late September of 2005, the Minnesota Department of Health (MDH) received several reports of E. coli O157:H7 illness among Minnesota residents and began conducting laboratory testing to determine whether the cases were related. Through pulsed field gel electrophoresis (PFGE) testing, commonly called DNA “fingerprinting” of the E. coli bacteria isolated from patients, public health investigators identified a single strain of E. coli O157:H7 that was causing illness and recognized that an E. coli O157:H7 outbreak was underway in Minnesota.
MDH epidemiologists conducted interviewed patients who had been laboratory-confirmed with E. coli O157:H7 infections and determined that all patients had consumed pre-packaged lettuce produced by Dole before becoming ill. On September 30, MDH issued a press release advising the public that 11 cases of E. coli O157:H7 had been identified in Minnesota residents who had eaten Dole lettuce purchased from at least four different stores in the Twin Cities area.
The MDH public health lab began testing Dole brand lettuce for E. coli O157:H7, and isolated the bacterium from a bag of lettuce. News of the positive lettuce specimen prompted the Food and Drug Administration (FDA) to issue a nationwide health alert regarding Dole pre-packaged salads on October 2. Although cases had only been identified in Minnesota, the product was noted to have been distributed nationwide, and it was not long before a E. coli O157:H7 cases from Wisconsin and Oregon were identified as part of the outbreak.
MDH ultimately counted 23 laboratory-confirmed cases of E. coli O157:H7 and seven epidemiologically linked cases. Two cases developed Hemolytic Uremic Syndrome (HUS). Oregon and Wisconsin reported one case each.
Marler Clark represented seven Minnesota, Wisconsin, and Oregon residents in claims against Dole. The claims were resolved in 2006 and 2007.