Penetration of Spoilage and Food Poisoning Bacteria into Fresh Chicken Egg: a Public Health Concern

Bacterial penetration shortly after inoculation has not been reported extensively. Four strains of bacteria, Salmonella typhimurium (ST), Escherichia coli (EC), Pseudomonas earuginosa (PE) and Stapylococcus aureus (SA), in chicken egg components of Bovan brown were analyzed by serial dilution and scanning electron microscopy. After exposing the fresh eggs to the bacterial strains at concentrations of 10 per ml, the egg components (eggshell, shell membrane, albumen and yolk) were examined at 30, 60, 90 and 120 min intervals. Untreated fresh eggs (controls) had no bacteria. Among the 4 strains, PE was the most dominant in the egg components followed by ST, SA and EC. In egg components the four strains generally demonstrated significant increase throughout the experimental period. However, there was a decrease in albumen in SA after 60 min. While in ST, there was a decline in both albumen and yolk after 60 min period. Overall, the porous structure of the eggshell and egg membranes facilitated rapid penetration. The aim of this investigation is to evaluate the rate of penetration in the chicken egg components shortly after inoculation with bacteria. Such studies may be of value in generating awareness of bacterial contamination, especially in hot climates such as Oman.