Salmonella typhimurium infection associated with raw milk and cheese consumption–Pennsylvania, 2007

In February 2007, the Pennsylvania Department of Health received reports, through routine electronic laboratory disease reporting, of two persons with recent laboratory-confirmed infections with Salmonella enterica serotype Typhimurium. Both persons had reported drinking raw (unpasteurized) milk from the same York County, Pennsylvania, dairy (dairy A). S. Typhimurium isolates from these persons had pulsed-field gel electrophoresis (PFGE) patterns that were indistinguishable by use of the XbaI restriction enzyme. The same month, the Pennsylvania Department of Agriculture (PDA) received reports of illness from raw-milk customers of dairy A. PDA obtained milk samples from the raw-milk bulk tank at dairy A, which yielded S. Typhimurium with a PFGE pattern that was identical to the pattern from patient isolates. On February 26, the Pennsylvania Department of Health and PDA launched an investigation to determine the source and scope of the outbreak. This report summarizes the findings of that investigation, which determined that 29 cases of diarrheal illness caused by S. Typhimurium were associated with consumption of raw milk or raw-milk products from dairy A. The findings underscore the need to inform policymakers and the public of the potential health risks associated with raw-milk consumption.