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Monday, December 12, 2016

Egg refrigeration to halt salmonella growth.

Eggs are most nutritious and economical foods, but special care is advised when handling and preparing fresh eggs and egg products to avoid food borne illness, commonly called food poisoning Salmonella prevalence in eggs is a major concern to the egg industry and various strategies are employed to keep eggs safe and healthy as possible. Eggs may appear normal but contain a bacteria referred to as Salmonella that can make people sick, especially if eggs are eaten raw or lightly cooked. Many predisposing and persistence factors have been evaluated include poor housing conditions with chicken houses very close each other e.g less than 15 metres, young hens housed in proximity to old hens (older than 70 weeks of age), and the presence of cattle in the vicinity. A recent study shows that refrigerating eggs reduces salmonella growth irrespective of egg sweating. A study by Janet Gradl (graduate student) and Pat Curtis, Auburn University; Deana Jones, USDA Agricultural Research Service and Ken Anderson, North Carolina State University, USA, indicated that Salmonella enteritidis (SE) prevalence in eggs is a major concern to the egg industry. The objective of the study was to assess the effect of egg sweating on SE penetration into shell eggs over a six-week period stored at 4 °C. A 2x2 factorial of SE inoculation and egg sweating was utilized. Inoculated eggs were exposed to 108 SE. Sweated eggs were sweated for approximately 80 minutes in a 32° C incubator. Shell rinse, shell emulsion, and egg contents were enumerated and assessed for prevalence of SE throughout 6 weeks of 4 °C storage. In week 1, the shell rinse SE inoculated/non-sweated treatment had significantly higher Salmonella counts than the other three treatments, where no SE was detected. After week 1, no SE counts were obtained from the egg shell rinse, shell emulsion rinse, or egg contents. A significant week by treatment interaction was found. During weeks 1, 2, and 3 the shell rinse non-sweated and SE inoculated (SN) treatment had significantly higher SE prevalence than the sweated and inoculated treatment (SS). During weeks 4, 5, and 6, there was no difference in SE prevalence between the SS and SN treatment. Egg sweating did not increase SE penetration into the shell emulsion across treatment or week (P<0.05).( The decreasing trend of SE prevalence obtained over the six-week period indicate that refrigeration is a very effective method to halt Salmonella growth. These results indicate that the current practice of egg sweating is not harmful to egg safety.