SALMONELLA CONTAMINATION IN COMMERCIAL EGGS AND AN EGG-PRODUCTION FACILITY

Egg samples were collected from various stages of an egg processing op eration and from the attached production facility. Salmonella was isol ated from 72.0% of all samples collected from the laying house environ ment. Recovery of Salmonella from flush water, ventilation fan, egg be lt, and egg collector samples were (positive samples/total samples col lected): 2/2, 4/4, 16/22, and 14/22, respectively. Salmonella was foun d on 7 of the 90 eggshells sampled before processing and 1 of 90 eggsh ells sampled after processing, but Salmonella was not found in the 180 eggs analyzed for internal contamination following processing. The on e eggshell found positive for Salmonella following processing was dete cted when the pH of wash water samples was lowest (10.19). The 60 isol ates from production facilities included the following Salmonella sero types: S. agona, S. typhimurium, S. infantis, S. derby, S. heidelberg, S. california, S. montevideo, S. mbandaka, and untypable. The 22 isol ates obtained from eggshells prior to processing were serotyped as S. heidelberg and S. montevideo. All five isolates obtained from eggshell s after processing were serotyped as S. heidelberg. These data suggest that although the shells of about 1% of commercial eggs are contamina ted with Salmonella, contamination of the internal contents of eggs wi th Salmonella is a rare event.