Egg white is poor in the nutrients needed by microorganisms and exhibits remarkable antimicrobial properties. Therefore, it participates in protecting both hatching and table eggs from bacterial contamination. This chapter offers a comprehensive overview of the natural defences of egg white and of key parameters controlling hygienic quality and bacterial growth in egg white. In Sections 2 through 4, major and minor egg white proteins with antibacterial properties are described, with particular emphasis on their mode of action and their relative importance. Section 5 discusses the physicochemical and environmental conditions influencing bacterial growth or the activity of antibacterial proteins. Section 6 then covers hen-associated factors influencing the natural defences of egg white. Finally, Sections 7 and 8 explore the physicochemical and antibacterial properties observed in egg white during egg storage and incubation. They also highlight innovative methods to maintain or increase egg white antimicrobial activities.