Penetration of Salmonella enteritidis and Salmonella heidelberg into Egg Yolks in an In Vitro Contamination Model

ABSTRACT Eggs that harbor Salmonella in their edible contents pose a significant risk of transmitting disease to consumers. Although Salmonella deposition inside yolks does not usually occur at a high frequency in naturally contaminated eggs, bacterial penetration through the vi-tellinemembrane could lead to rapid and extensivemulti-plication in the nutrient-rich yolk contents. The present study used an in vitro egg contamination model to assess the ability of Salmonella strains to penetrate the vitelline membrane and multiply inside yolks. An S. enteritidis strain and 2 Salmonella heidelberg strains, initially inocu