Risk Assessment of Shell Eggs Internally Contaminated with Salmonella Enteritidis

Abstract

A risk assessment was performed to determine the health risks associated with the consumption of Canadian grade A eggs internally contaminated with Salmonella Enteritidis. The distribution of the prevalence of contaminated eggs yielded an average of 1.7 per million from regulated laying flocks. The poorest storage and handling conditions for eggs represent 0.6% of exposures but result in 46% of illnesses; eggs handled under ideal storage and handling conditions account for 96% of exposures and represent 49% of illnesses. These findings suggest that risk management options targeting contaminated egg prevalence and the number of illnesses from a contaminated egg would be appropriate. Simulated risk management strategies included i) vaccination of flocks moving into houses previously occupied by positive flocks, ii) test and divert flock management strategy with environmental testing for S. Enteritidis, iii) eliminating the use of pooled shell eggs in foodservice and institutional settings, and iv) eliminating S. Enteritidis growth by improving egg storage and handling conditions. Strategies aimed at flock management yielded simulated reductions in contaminated egg prevalence between 2 and 29% of baseline, with smaller simulated gains from strategies aimed at reducing the number of illnesses per contaminated egg.