Two weeks ago, Foster Farms poultry producers announced they’d dramatically lowered levels of salmonella in chicken parts — and invested $75 million to do it.

Now, Foster Farms of Fresno, Calif., is recalling an undetermined amount of chicken products that may be contaminated with a particular strain of Salmonella Heidelberg.

The U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS) requested Foster Farms conduct this recall because this product is known to be associated with a specific illness.

FSIS was notified by the Centers for Disease Control and Prevention (CDC) of a Salmonella Heidelberg illness on June 23, 2014, associated with the consumption of a boneless skinless chicken breast product. Working in conjunction with CDC, FSIS determined that there is a link between boneless skinless chicken breast products from Foster Farms and this illness after recovering the leftover boneless chicken breast for testing. Lab tests confirmed a molecular match between the Salmonella on the cut-up poultry and strains infecting the patient.

This illness is part of an ongoing outbreak being monitored and investigated by FSIS and CDC. Until this point, there had been no direct evidence that linked the illnesses associated with this outbreak to a specific product or production lot. Evidence that is required for a recall includes obtaining case-patient product that tests positive for the same particular strain of Salmonella that caused the illness, packaging on product that clearly links the product to a specific facility and a specific production date, and records documenting the shipment and distribution of the product from purchase point of the case-patient to the originating facility.

It’s a sad day for epidemiology, with Foster Farms fingered in at least 575 cases of Salmonella Heidelberg since March 2013.

The newly recalled products subject to recall bear the establishment number “P6137,” P6137A” or “P7632” inside the USDA mark of inspection. The chicken products were produced on March 8, 10 and 11, 2014. These products were shipped to Costco, Foodmaxx, Kroger, Safeway and other retail stores and distribution centers in Arizona, California, Colorado, Idaho, Montana, New Mexico, Nevada and Utah.