In February, the Pennsylvania Department of Health received reports of two laboratory-confirmed infections of Salmonella Typhimurium. The isolates matched by pulse-field gel electrophoresis (PFGE), a genetic fingerprinting technique, and the patients shared a common exposure to raw milk from Stump Acres Dairy. Pennsylvania Department of Agriculture obtained samples of the dairy's raw milk, and these tested positive for S. Typhimurium, and were a PFGE match to the other samples. Three distinct clusters were found. The first cluster of 15 contracted the illness between February 3rd and March 5th. Milk from the dairy was tested on February 20th and 28th and found to contain S. Typhimurium. Pennsylvania Department of Agriculture ordered the dairy to halt sales and inform the public of the threat. On March 19th, the dairy was allowed to resume sales after two tests of the milk were negative. The second cluster was associated with milk consumption between March 19 and March 27, when the dairy was ordered to stop sales. One case consumed the raw milk in the form of queso fresco made by an unlicensed producer who bought milk from Stump Acres Dairy. The dairy's raw milk permit was suspended on March 27th. The third cluster began in June; ten of the eleven PFGE-matched, S. Typhimurim cases lived near Stump Acres Dairy. Investigators found that the dairy had been distributing raw milk despite their suspended license.