Purpose: The purpose of this study was to evaluate factors affecting Salmonella growth dynamics in concentrated shell egg preenrichment, such as cell history, genetically diverse strains, and contamination ratio.
Methods: Homogenized albumen and whole egg aliquots were contaminated with eight egg and clinical Salmonella strains, representing seven serotypes, at two concentration levels. Preenrichment samples were inoculated with cold-adapted samples per BAM protocol. Salmonella growth was determined by plate count methods. Growth parameters were analyzed by the Baranyi model.
Results: Overall, growth rates in concentrated BAM shell egg preenrichment were similar for all strains evaluated. Lag phase duration was significantly different (p < 0.001) for serotype, contamination level, and prior exposure to albumen or whole egg at low temperature. However, maximum growth in preenrichment cultures exceeded 7-log cell concentration for all samples tested.
Significance: Our study provides evidence the revised Salmonella BAM shell egg preenrichment medium supports recovery of diverse and injured Salmonella cells to sufficient levels for detection by a rapid screening qPCR assay.