On September 18, 2006, the California Department of Health Services (CDHS) opened an investigation of a possible outbreak of E. coli O157:H7 infections after receiving reports of two patients who had been hospitalized with HUS. One was culture confirmed as infected with E. coli O157:H7. Interviews revealed that both patients had consumed unpasteurized cow milk sold by Organic Pastures in the week prior to the onset of illness.
In the following days, four additional cases of E. coli O157:H7 were identified. All of the additional cases had consumed raw milk or raw cow product sold by Organic Pastures. Isolates of the E. coli O157:H7 cultured from the five culture-positive patients had indistinguishable “genetic fingerprints” as determined by pulsed-field gel electrophoresis (PFGE) testing. These PFGE patterns were new to the national PulseNet database. In other words, the pattern associated with all of these children was unique, and had not been seen before in conjunction with any other outbreaks of E. coli O157:H7. In addition, the PFGE pattern differed markedly from the patterns associated with the outbreak of E. coli O157:H7 associated with Dole fresh-bagged baby spinach that had peaked a few weeks prior to these illnesses.
CDHS conducted an epidemiological and environmental investigation of the cluster of illnesses. A review of 50 consecutive E. coli O157:H7 cases reported to CDHS from October 2004 to June 2006 revealed that 46 of 47 cases asked about raw milk consumption reported consuming no raw milk. In contrast, five of the six patients in the cluster being investigated reported definite consumption of Organic Pastures raw dairy products. The sixth denied consuming the raw milk, but his family routinely consumed Organic Pastures raw milk during the suspected time frame. Two of the children developed Hemolytic Uremic Syndrome. This is the video of one of the children in the hospital:
The California Department of Food and Agriculture conducted an environmental investigation. As part of the investigation, fecal samples were collected from dairy cows at Organic Pastures. E. coli O157:H7 was isolated from five of the samples, although the PFGE patterns differed from the pattern associated with the outbreak. Testing of Organic Pastures product revealed abnormally high aerobic plate counts and fecal coliform counts. CDHS ultimately concluded: “the source of infection for these children was likely raw milk products produced by the dairy.”