Development and application of a risk assessment tool for preventing the introduction and transmission of Salmonella in poultry farms: Based on the Delphi-analytic hierarchy process.

A semiquantitative risk assessment method based on the Delphi-analytic hierarchy process (AHP) can serve as a proactive tool for the prevention and control of Salmonella infections in poultry farms. This method can facilitate early warning to minimize the risk of transmission of Salmonella to chicken meat and eggs. In this study, an expert panel comprising 22 members was established. After two rounds of evaluation, a risk assessment system consisting of 10 primary indicators and 73 secondary indicators was finalized. The expert participation rate (100 %), authority coefficient (1.0), and Kendall's W value (0.222 for the first round and 0.316 for the second round) met the required standards. Moreover, the system exhibited high reliability and validity. Based on the AHP, the top three weighted primary indicators were "seedstock management" (0.2769), "feeding and management" (0.1429), and "cleaning, disinfection and harmless disposal" (0.1429). The combined weight of the secondary indicators ranged from 0.00009 to 0.03027. In total, 6423 samples, including dead embryos and environmental samples, were collected from a poultry farm. By isolating Salmonella, assessing antimicrobial resistance, and performing whole-genome sequencing, the key risk points for contamination were identified. The implementation of targeted control measures based on the risk assessment model resulted in significant improvements. In particular, the overall antibody positivity rate decreased from 65.9 % to 8 %, the isolation rate of Salmonella from dead embryos decreased from 47.5 % to 3.75 %, and the isolation rate of Salmonella from the production environment of the hatchery workshop decreased from 10.1 % to 0.9 %. Moreover, notable improvements were observed in production metrics. Overall, our established risk assessment model is suitable for environments with low Salmonella isolation rates and can effectively facilitate the prevention and control of Salmonella in poultry farms.