An examination of eggshell pore structure and penetration by 'Salmonella' typhimurium

The horizontal infection of table eggs by food-poisoning causative agents such as 'Salmonella' is a serious concern for consumers and industry. While there are some factors that are associated with increased rates of infection the mechanism of bacterial entry remains unknown. The use of Computed Tomography (CT) enables the production of transverse images of the shell's interior. This imaging has allowed for identification of alternative pore structures, branching pores have been found, and both internally and externally branching pores are present in egg shells of laying hens. Using the agar egg penetration method first described by Board and Board (1967), the contents of 208 eggs were removed and the shells filled with molten XLD agar.