Development of an Updated and Optimized Egg Quality Assurance Program to Minimize Salmonella Enteritidis Contamination of Shell Eggs

Non-Technical Summary: <BR>Salmonella Enteritidis (SE) is a leading foodborne pathogen in the US with many outbreaks in humans traced back to shell eggs. As a result, the implementation of effective strategies for reducing SE in commercial layer flocks has become a critical public health and economic objective. The overall goal of this proposal is to integrate applied research and outreach to develop an updated and optimized Egg Quality Assurance Program (EQAP) that will significantly reduce SE contamination of shell eggs. The supporting aims are to: (1) determine the routes by which SE is transmitted to eggs in the production environment; (2) determine the effect of management practices including vaccination on SE contamination of eggs; (3) analyze the above information to establish critical control points (CCPs) and improve the Pennsylvania EQAP (PEQAP); (4) evaluate the effectiveness of PEQAP before and after it is optimized; and (5) disseminate the updated and optimized EQAP to industry, government and academic institutions. In order to accomplish the overall goal, we will monitor medium- and small-sized layer farms in Pennsylvania and Iowa for SE before and after implementing PEQAP, followed by tracking the routes of transmission from source to eggs by molecular subtyping of SE isolated from the poultry house environment, eggs, rodents, feed and flies. Knowledge gained will be disseminated to poultry producers and stakeholders through extension programs, meetings, workshops, and educational materials. We expect that this study will accurately identify CCPs, and thus update and optimize PEQAP for use by producers throughout the U.S. to prevent SE contamination of shell eggs. This will potentially lead to decreased SE infection from eggs, thus improving public health and economic opportunities for poultry farmers. Expected outcomes/impacts. At the end of the project, we expect multiple outcomes from this project. These include: 1) A better understanding of the routes by which SE is transmitted to eggs; 2) A better understanding of the role of farm size, multiple species farms and vaccination on SE contamination of commercial layers; 3) A more accurate identification of Critical Control Points (CCPs) that can be implemented to prevent SE contamination of shell eggs; 4) Development of an updated and optimized EQAP based on research findings and delivery of the tools, skills, and practices to egg producers through extension and outreach training; 5) A trained cadre of poultry producers and technicians that can effectively implement the updated and optimized EQAP in Pennsylvania, Iowa and other states; 6) improvement in consumer confidence in the safety and quality of shell eggs. Finally, we will have developed a research and extension infrastructure that will serve the commercial egg industry for many years beyond the life of this project. <P> Approach: <BR> Monitoring. A total of forty medium- and small-sized flocks (3,000-50,000 and less than 3,000 bird flocks, respectively) in Iowa and equivalent operations in Pennsylvania will be monitored over one egg laying period (300+ days) before and after implementation of the optimized EQAP. Drag swabs, mice, flies, feed, water, and egg samples will be collected until the end of production. Bacteriological examination will be performed according to the FDA Bacteriological Analytical Manual (BAM) protocols. Any group D Salmonella isolated will be serotyped. Subtyping. Any SE isolated will be subtyped using pulsed-field gel electrophoresis (PFGE) and CRISPR-based molecular typing, which is a novel method developed by PIs. Dissemination. The updated and optimized EQAP will be disseminated to industry, government and academic institutions in PA, IA and other states using the following activities/instruments: i. Revise PSU Publication (01/03/03)AGRS-072 / Preharevest HACCP in the Table Egg Industry: Hazard Analysis Critical Control Point System for Enhancing Food Safety (also post on web) ii. Develop Presentation Power Points like PEQAP: Assemble into a Training Notebook for each Participant. iii. Develop and Maintain a Web site iv. You-Tube videos to post on web (pullet chick paper swabs, environmental swabs, egg sampling when environments positive) v. Certification Testing instrument (in person and web based) vi. Certificated program after completion and testing vii. Make continuing Ed Credits available viii. Optional 3rd Party Mock Farm Inspections & Reviews in years 2 and 3 (100 per state) ix. Hold in state training sessions (IA & PA) to certify producers (6 sessions per state) x. Maintain website for further in-state training and certification and sharing with the greater US egg industry Means by which data will be analyzed or interpreted: a. The comparison of SE prevalence rates before and after implementation of EQAP will be assessed using McNemar's chi-square test. A P value < 0.05 will be considered as a difference in SE prevalence (SAS statistical software). b. Analysis of risk factors for SE. An analysis of risk factors for SE on layer premises will be based on the results of various samples collected at different time points. Exact odds ratios (OR) and 95% confidence intervals (95% CI) will be calculated for each explanatory variable using SAS statistical software. c. Molecular Subtyping. We will calculate discriminatory power (D) and epidemiologic concordance (E) for both PFGE and CRISPR-MLST using the formulas defined by the European Society for Clinical Microbiology and Infectious Diseases. Isolates that lack epidemiologic information (ie., an association or lack of association with a defined outbreak is unknown) will be excluded from the calculation of E. Evaluation methods or means by which extension activities will be evaluated: A combination of two evaluation models/frameworks will be used to evaluate the project. These include: Kirkpatrick's Training Evaluation Model, and Stufflebeam's (1983, 2003) CIPP models. Collectively, these two models will assist in documenting the outcomes of this project.