This Is AuburnElectronic Theses and Dissertations

Microbial Analysis of Shelled Eggs and Chemical and Functional Analysis of Liquid Eggs




Kretzschmar-McCluskey, Vanessa

Type of Degree



Poultry Science


Research has shown that the incidence of Salmonella Enteritidis (SE) in commercially processed table eggs is approximately 1 in 20,000. Although there has been great evolution of the egg industry, cases of SE infection continue to be problematic. It has been shown that through environmental maintenance and proper processing and storage practices, the number of reported SE outbreaks has declined Although numerous studies have been conducted outlining possible vectors and modes of transmission through inoculation of laying hens, there is little information regarding the natural occurrence of SE in shell eggs. From these experiments, it was concluded that hen age had a significant impact on the amount of microbial contamination, while hen strain had no effect. It was also determined that each of the three molting treatments contained significant amounts of microflora, with the non-fasted treatment exhibiting 4 interior samples that were positive for Salmonella Braenderup over the course of the final 12-month portion. There was no evidence of Salmonella Enteritidis discovered with any treatment during the course of the experiment, and none of the Salmonella spp. discovered in the environmental samples could be correlated to the species found in the shell eggs. Because of the concern surrounding the bacterial content of shelled eggs, over 30% of those sold today are sold as pasteurized egg products. Pasteurization virtually eliminates bacterial pathogens from eggs by holding them at a high temperature for an amount of time which is specific to the particular product. However, previous research has shown that the pasteurization process can be detrimental to the functionality of eggs, causing problems for the baking industry. The results of these experiments concluded that the theory of pasteurization being detrimental to the functionality of whole egg products was not applicable to this study. The albumen portion of this study utilized the same treatments with the exception of the addition of a triethyl citrate whipping agent instead of citric acid. The results indicated that the addition of whipping agent to pasteurized product greatly improved functionality while having no effects on chemical composition.