Technical Abstract: An international increase in human S. enteritidis infections has been associated primarily with the consumption of internally contaminated eggs. Governments, consumers, and the poultry industry have accordingly become very interested in the microbiology of eggs and egg products. Systemically infected laying hens sometimes deposit this pathogen inside developing eggs s(although this seems to occur at a very low incidence and typically involves small bacterial levels). In recent years, diverse microbial quality assurance programs have been developed and implemented to control SE. Common features of such programs include using uninfected chicks, effective pest control, thorough cleaning and disinfection of poultry facilities, heightened biosecurity practices, and adequate washing and refrigeration of eggs. Flocks are sometimes tested to verify the effectiveness of these control measures. In combination with intensified efforts to ensure that eggs will be handled, prepared, and consumed safely widespread participation in quality assurance programs may be the most cost-effective strategy for achieving long-term reductions in the incidence of egg-transmitted illness due to SE.