The E.coli contamination that affected romaine lettuce nationwide at least partly came from a California farm, officials said Thursday.
The U.S. Food and Drug Administration and the US Centers for Disease Control and Prevention tracked a positive sample to the sediment of a local irrigation reservoir used by a single farm owned and operated by Adam Bros. Farms in Santa Barbara County.
It's unclear how the reservoir became contaminated, officials said.
The lettuce distributed from Adam Bros. Farms is also not responsible for the entire outbreak, according to the FDA.
Owners at the farm were cooperating with the investigation and haven't shipped out any lettuce since Nov. 20.
The agencies warned consumers to continue avoiding romaine lettuce from Monterey, San Benito and Santa Barbara counties as a precaution.
As of Thursday, 59 illnesses had been reported in 15 states due to the contaminated lettuce, according to the CDC.
