Late in August 2006, the federal Centers for Disease Control and Prevention in Atlanta began investigating cases of severe food poisoning reported by health officials in 26 states and one Canadian province. Over the next six weeks, a rare and particularly virulent strain of Escherichia coli 0157:H7 sickened more than 200 people across North America, hospitalizing half of them, some with severe kidney damage, and killing two elderly women and a child. For epidemiologists, the outbreak presented a breakthrough because a DNA-fingerprinting system enabled CDC investigators to trace the source of the infections from clusters of cases nationwide.
Bacteria in stool samples of hospitalized patients were genetically matched to pathogens in packaged, “ready to eat” Dole brand spinach that they had recently purchased and consumed. Further, product codes on the bags indicated that the contaminated greens had been processed during one shift on Aug. 15 at a plant in San Juan Bautista then owned and operated by Natural Selection Foods. The company’s records showed that the spinach had been harvested from four fields in Monterey and San Benito counties.