Bacteriological contamination of egg products after thermal preservation processes

Research was carried out to define the hygienic propriety of thermally treated eggs, i.e. eggs treated at pasteurization temperatures and those stored frozen. The average values of the number of the bacteria in the pasteurized yolk and egg white were log 4.9 and 5.1, respectively, those in the frozen-pasteurized yolk and egg white were log 5.5 and 4.8 and in the frozen yolk and white were log 7.0 and 5.9. The contaminants Salmonella spp., Proteus spp., Staphylococcus aureus, Escherichia coli, Clostridium spp., Clostridium perfringens, Pseudomonas spp.. Campylobacter jejuni and Yersinia enterocolitica were tested for 306 samples of pasteurized, frozen and pasteurized and frozen products of eggs, egg-yolks and egg-whites. Presence of Salmonella spp. in the pasteurized yolk was 12%, Clostridium spp. 16%, E. coli 16% and Proteus spp. 14%, but in the pasteurized egg white those bacteria were present in 10.8%, 15.3%, 13.8% and 10.0%. Staphylococcus aureus was isolated in yolk at 4.6 and in white 4.0% and Clostridium perfringens 4.0 and 1.5%, respectively. The bacteriological flora indicated that the degree of contamination of egg-products depends directly on the degree of initial contamination and correlates with the technological egg-treatment processes applied.