Isolation, Identification, and Characterization of Foodborne Pathogens Isolated from Egg Internal Contents in China

Eggs continue to be significant in terms of the world economy and human nutrition. The aim of this study was to estimate the prevalence of foodborne pathogens in a cross section of egg production types in China and to examine the virulence features of the isolated pathogens. Three hundred eggs from three provinces were tested for Salmonella , Escherichia coli , Staphylococcus aureus , and Campylobacter . Two eggs were positive for Salmonella , one was positive for both E. coli and S. aureus , and none were positive for Campylobacter . When comparing different egg laying systems, there were no significant differences in findings between packaged and unpackaged eggs and between battery cage and cage-free eggs, but there were significant differences in the findings among pathogens and among provinces. Other potential foodborne pathogens were identified in addition to the targeted pathogens. The virulence of Serratia marcescens was higher than that of the isolated Salmonella Typhimurium, and the virulence of Staphylococcus saprophyticus was comparable to that of the isolated S. aureus . These findings are important for local risk assessments concerning possible human foodborne infections via cross-contamination of eggs.