The FDA and the State of California announced today that test results from a field investigation of the outbreak of E.coli O157:H7 in spinach was found to be positive for E.coli O157:H7. Samples of cattle feces on one of the implicated ranches tested positive based on matching genetic fingerprints for the same strain of E. coli that sickened 199 people.

An FDA News report says that the trace back investigation has narrowed to four implicated fields on four ranches. The outbreak strain of E. coli O157:H7 from cattle feces was identified on one of these four ranches. At this time, testing of other environmental samples from all four ranches that supplied the implicated lot of contaminated spinach are in progress. The positive test result is a significant finding, but is just one aspect of this investigation. More information may come forward as the investigation continues.

The four fields, located in Monterey and San Benito counties, are not currently being used to grow any fresh produce. While the focus of this outbreak has narrowed to these four fields, the history of E. coli O157:H7 outbreaks linked to leafy greens indicates an ongoing problem. As the FDA stated in its letter to the lettuce industry in November of 2005, the FDA continues to be concerned due to the history of outbreaks and the on-going risk for product contamination of leafy greens.

This investigation is on-going. FDA, the State of California, the Centers for Disease Control and Prevention and the United States Department of Agriculture are continuing to work closely to determine the cause and scope of the E. coli O157:H7 outbreak linked to fresh spinach.