Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/1/2004
Publication Date: 8/1/2005
Citation: Gast, R.K., Holt, P.S., Murase, T. 2005. Penetration of salmonella enteritidis and s. heidelberg through the vitelline membrane in an in vitro egg contamination model. Proceedings of the International Poultry Scientific Forum. 84(1):93.
Technical Abstract: Eggs containing Salmonella in their edible contents pose a significant threat to transmit disease to consumers. Although Salmonella deposition inside yolks is a highly infrequent event in naturally contaminated eggs, bacterial penetration through the vitelline membrane could result in rapid and extensive multiplication in the nutrient-rich contents of the yolk. The present study used an in vitro egg contamination model to assess the ability of Salmonella strains to penetrate through the vitelline membrane and multiply inside yolks. After inoculation onto the outside of vitelline membranes, an S. enteritidis strain and two S. heidelberg strains were all able to enter the yolk contents (at frequencies ranging from 10 to 25% of experimentally contaminated eggs) during 24 hours of incubation at 30° C. Variants of these parent strains, obtained by in vivo passage into eggs laid by infected hens, penetrated through the yolk membrane at significantly higher frequencies. These results emphasize the importance of prompt refrigeration for minimizing the opportunities for pathogens such as S. enteritidis and S. heidelberg to multiply and attain more dangerous levels after penetration into the yolks of contaminated eggs.