Survival of inoculated Salmonella on the shell of hens' eggs and its potential significance

• Published in: Food control Vol. 28; no. 2; pp. 463 - 469
• Main Authors: Botey-Saló, Pilar, Anyogu, Amara, Varnam, Alan H., Sutherland, Jane P.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2012
• Subjects: Colony-forming cells; Eggs; Monte Carlo simulation; Salmonella; Survival; Salmonella; Survival; Eggs; Monte Carlo simulation
• ISSN: 0956-7135; 1873-7129
• DOI: 10.1016/j.foodcont.2012.05.033

The aim of this research was to evaluate the risk of inoculated Salmonella persisting on the outside of the shell of hens' eggs. Hens' eggs were surface inoculated with a cocktail of Salmonella strains and stored for up to 54 days at 4, 10 and 20 °C and at 80 and 90% relative humidity. Salmonella survival showed an irregular pattern, with extremes of high recovery and no recovery. However, salmonellae were always recovered after resuscitation. Monte Carlo simulation of different scenarios using relevant assumptions indicated that the distribution of surviving Salmonella was skewed towards low numbers, suggesting higher chances of Salmonella persisting on the eggs in low numbers (<104 cfu egg−1). Although numbers were low, the research demonstrated the ability of salmonellae to survive on the shells of eggs following contamination and this clearly has safety implications for handling of eggs in the food industry and the domestic environment. ► Salmonella Enteritidis can survive on the surface of hens' eggs for up to 54 days. ► Pulsatile recoveries were recorded at 10 and 22 °C, more consistent recovery at 4 °C. ► Inoculated Salmonella was always recovered from eggshells following resuscitation. ► Risks were assessed using Monte Carlo simulation based on experimental results. ► Survival has food safety implications for domestic and commercial food handlers.