GROWTH AND HEAT-RESISTANCE OF SALMONELLA-ENTERITIDIS IN REFRIGERATED AND ABUSED EGGS

The effect of storage temperature on the growth and heat resistance of Salmonella enteritidis (SE) in eggs artificially inoculated with 20 C FU per egg has been investigated. SE organisms grew to a stationary ph ase (1 x 10(9) CFU/ml of egg) within 2-3 d after storing the eggs at r oom temperature (23-degrees-C), while minimal or no growth occurred in similarly inoculated eggs that were refrigerated at 4-degrees-C. None of the common methods of egg cooking was found totally effective in e liminating SE organisms in massively contaminated eggs. SE organisms s urvived in significantly higher proportions of the eggs that were stor ed at 23-degrees-C than in refrigerated eggs after cooking by differen t methods (P < 0.05). Higher rates of Salmonella survival after cookin g were detected in the eggs that were stored at room temperature for 5 d or longer than in eggs stored for shorter time (P < 0.05). Data fro m this study indicated: i) storage abuse of eggs can be a major factor in increasing the prevalence of eggborne SE infections by increasing the infectious load and heat resistance of the SE organisms in the con taminated eggs, and ii) that breaking and pooling of eggs immediately before cooking can minimize the substantial multiplication of SE organ isms from slightly contaminated eggs. Refrigeration, therefore, can be a significant barrier against SE infections through its growth inhibi tory and heat resistance-reducing effects on the SE organisms in conta minated shell eggs as well as in large volumes of liquid eggs intended for pasteurization.