Submitted to: Proceedings of Iowa Egg Symposium
Publication Type: Proceedings
Publication Acceptance Date: November 18, 2009
Publication Date: November 11, 2009
Citation: Gast, R.K. 2009. Salmonella Control in Laying Flocks: The Scientific Background. Proceedings of Iowa Egg Symposium: pp.1-7, 2009. Technical Abstract: More than 2500 distinct Salmonella serotypes have been identified, but only a small fraction of these are commonly found in poultry flocks. However, poultry products are epidemiologically important as sources of Salmonella transmission to humans and several of the serotypes that most often cause human illness (such as S. Typhimurium and S. Enteritidis) are highly prevalent in commercial poultry. In recent years, the scope of efforts to ensure the microbial safety of poultry products has been expanded to include more attention to animal production (pre-harvest) issues. Pre-harvest Salmonella control focuses on reducing opportunities for the introduction, persistence, and transmission of this pathogen in breeder, broiler, or egg-laying flocks. Some strategies for attaining these goals are broadly effective against a wide spectrum of Salmonella serotypes (and even against other pathogenic microorganisms), whereas other strategies are specifically designed to act with more precision against particular Salmonella serotypes that have heightened public health or economic significance. Risk assessment studies have usually recommended intervention at multiple steps in the farm-to-table continuum as the most productive overall approach to Salmonella control. A comprehensive quality assurance strategy, employing both broadly oriented risk reduction practices that are active against all serotypes and targeted testing to detect serotypes of predominant epidemiological relevance, has been associated with a lower incidence of S. Enteritidis infections in both egg-laying flocks and humans in a number of countries. Although these programs typically emphasize the significance of risk reduction practices for achieving their objectives, testing provides essential verification of the efficacy and cost-effectiveness of these practices (and identifies flocks infected with uniquely problematic serotypes). Vaccination against specific serotypes of elevated public health importance can provide a valuable tool for enhancing the short-term responsiveness of control programs.