By Annys Shin
Washington Post Staff Writer
Friday, October 27, 2006
Investigators have matched E. coli found in a stream and in a wild pig on a California ranch to the strain of bacteria that caused last month's deadly spinach-borne outbreak.
Investigators have nine positive specimens from the same farm, which has spinach fields and livestock. Those samples were gathered within a mile of spinach fields implicated in the outbreak, said Kevin Reilly, deputy director of the California Department of Health Services.
Food safety experts do not know how far apart livestock operations and vegetable fields should be to prevent E. coli contamination, he said.
The discoveries of the outbreak strain in creek water and in a wild pig's gastrointestinal tract suggest how E. coli could have found its way onto spinach crops.
The farm uses irrigation water that comes from wells within a mile of the stream bed. The wells are supplied by the same aquifer as the stream.
"The question is: What is the connection between the stream bed and the aquifer from which the well water is being drawn?" Reilly said.
Investigators have found evidence that pigs had broken into the spinach fields, and the pigs could have transferred E. coli to the fields by tracking infected cattle feces there or through their own infected feces.
But investigators said they have not ruled out other sources of contamination, including three other Salinas Valley, Calif., farms that remain under investigation.
E. coli -contaminated spinach has sickened 204 people in 26 states and Canada, with three deaths confirmed. Health officials also said yesterday that the outbreak is probably over.