A public health alert was issued today for raw chicken produced by Foster Farms and distributed at retail outlets primarily in California, Oregon and Washington.

Although federal inspectors are unable to pinpoint any specific Foster Farms products or production periods, their investigation into 278 cases of Salmonella Heidelberg in 18 states has led them to conclude the source of the illnesses can be traced back to chicken products produced in three of the company’s California facilities. Most of the illnesses were reported in California.

Foster Farms said it is cooperating with the U.S. Agriculture Department’s Food Safety and Inspection Service and with the Centers for Disease Control and Prevention in the ongoing investigation.

According to federal authorities, raw products from the facilities in question bear one of the following numbers somewhere on the package: P6137, P6137A, P7632.

The Agriculture Department and the company urged consumers to always properly handle raw poultry and to follow cooking instructions found on the packaging. Foster Farms also pointed out that no recall has been ordered and that it has instituted additional food safety practices in its Pacific Northwest operations.