2011 Annual Report 1a.Objectives (from AD-416) The proposed objectives are:. 1)to conduct on-farm surveys in organic and all natural poultry production practices to determine the prevalence and diversity of Salmonella serovars in these production systems as compared to more intensive commercial systems;. 2)to develop and evaluate intervention strategies targeting control of Salmonella during the feed withdrawal and transportation processes prior to slaughter of broiler chickens to minimize cross contamination during transport and slaughter;. 3)to evaluate post-harvest interventions to control Salmonella using novel antimicrobials in pre- and post-chiller applications, for both water and air chilling, and for finished raw products; and. 4)to develop risk assessment models that can be adapted to organic and all natural production and processing systems. The proposed research will generate multiple publications in peer-reviewed scientific journals, presentations in meetings, and annual updates as well as a complete final report to the funding agency. 1b.Approach (from AD-416) A minimum of 10 flocks from each production system will be sampled during grow-out. Chick box paper pads from each production system will be collected from a minimum of 10 boxes and will be sampled. Each flock will be sampled on at least 3 occasions and 6-10 of each sample type will be collected during each sampling occasion. Salmonella parameters will be evaluated on each sample collected:. 1)isolation frequency;. 2)serotype diversity;. 3)antimicrobial resistance pattern; and. 4)genotype diversity. 3.Progress Report On-farm Salmonella prevalence surveys have been completed. Salmonella enterica serovar Kentucky was the most commonly recovered serovar. Salmonella strains isolated from pasture-raised poultry also exhibited antimicrobial resistance phenotypes and genes. The project has been extended for an additional year to perform detailed genotyping analyses of selected strains. Several pre- and post-harvest intervention strategies have been evaluated. A combined thermal and acidified sodium propionate treatment has been identified as an effective post-harvest intervention to control Salmonella contamination of poultry products. Specific risk assessment models are currently being developed. The Principal Investigator monitors the progress of the study by coordinating frequent conference call meetings, in addition to individual meetings whenever team members attend scientific events throughout the year.