Survival of Salmonella in waste egg wash water

Waste wash waters from chicken egg-processing facilities can harbor high densities of bacteria, including salmonellae. For this study, we enumerated total coliforms, Escherichia coli, and Salmonella spp. in the egg wash waters of a large egg producer. We then determined how long these organisms would survive at temperatures of 5, 15, and 25 degrees C. We found that the fraction of salmonellae surviving over time at a given temperature was comparable to the fraction of indicator organisms that survived. We also found that the survival of these organisms varied with temperature, with 16, 8, and < 2 days being required for a 90% reduction of Salmonella in waste wash water held at 5, 15, and 25 degrees C, respectively. Finally, we noted that the response of laboratory-derived cultures to environmental stresses mimics the response of the indigenous microbial population, but individual cells within that population may survive for longer periods than laboratory-cultured strains.