Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/28/2021
Publication Date: 6/18/2021
Citation: Gast, R.K. 2021. Salmonella control in egg-laying chickens: Understanding how and why. Proceedings of Shell Egg Academy, June 21-25, 2021. pp.9-13.
Technical Abstract: Contaminated eggs have been internationally significant sources for the transmission of Salmonella infection to humans for several decades. Both the public and private sectors have invested substantial resources in comprehensive risk reduction and monitoring programs for Salmonella in commercial egg-laying flocks. The most effective overall strategy for controlling Salmonella in layers has been the application of multiple interventions throughout the egg production cycle. Although a large proportion of egg-transmitted illness is attributed to Salmonella serovar Enteritidis, other serovars (notably S. Heidelberg and S. Typhimurium) are also implicated. Contamination of the edible interior contents of eggs with S. Enteritidis results mainly from colonization of the reproductive tissues of systemically infected laying hens, although salmonellae can also penetrate through eggshells after contamination of the exterior surface. Managing storage temperatures is vital for limiting the growth of Salmonella growth inside eggs. Managing environmental and housing conditions for laying flocks is critical for reducing opportunities for the introduction, transmission, and persistence of Salmonella. Different hen housing systems for commercial egg production influence these environmental parameters, and unique risk factors and management challenges are characteristic of each system.