An outbreak of Yersinia enterocolitica infections was associated with drinking milk or eating ice cream made by the Brunton Dairy. Nine individuals in Beaver County and seven in Allegheny County were sickened. On August 26, investigators reported that Yersinia enterocolitica was found in an unopened container of Brunton Dairy ice cream. Later Yersinia enterocolitica was isolated from homemade yogurt made from the dairy's milk. Through home delivery and retail sales, Brunton's Dairy distributed approximately 10,000 milk containers per week to 650 households and 40 retail outlets. The mechanism of milk and ice cream contamination was unknown. The dairy resumed milk production and distribution following a Pennsylvania Department of Agriculture culture of a test batch of products that demonstrated no growth of Yersinia. No additional outbreak-associated cases of Yersinia were reported after August 5. The dairy farm had been operated by the Brunton family since 1832 and had bottled milk beginning in 1964.