Salmonella and Campylobacter prevalence and concentration on pasture-raised broilers processed on-farm, in a Mobile Processing Unit, and at small USDA-inspected facilities

•Most pasture-raised broilers processed by the three methods were contaminated with Salmonella and/or Campylobacter.•Salmonella prevalence and concentrations were higher for birds processed on-farm compared to USDA facilities.•Salmonella was not detected on carcasses processed in the MPU pilot plant.•Campylobacter prevalence was no significantly different on carcasses processed by the three methods.•Campylobacter concentrations were higher for birds processed in the MPU compared to on-farm and USDA facilities.

The small-scale, pasture-raised poultry production model is a growing niche in the locally grown food movement. Research that focuses on the food safety of small-scale broiler processing methods is limited. The objective of this study was to compare Salmonella and Campylobacter prevalence and concentrations on pasture-raised broilers processed on-farm, in a small United States Department of Agriculture - Inspected slaughter facility (USDA-IF), and in a Mobile Processing Unit (MPU) pilot plant. A total of 120, 100, and 50 post-chill, pasture-raised broiler carcasses were sampled from each processing method, respectively. Pathogen prevalence and concentrations from whole carcass rinses were determined using a 3-tube Most Probable Number (MPN) method for Salmonella and direct plating method for Campylobacter according to the USDA-Food Safety and Inspection Service (FSIS) protocols. Both Salmonella prevalence and concentrations on-farm (89% and 1.78 MPN/carcass [95% CI: 1.60-1.96]), USDA-IF (43% and 0.78 MPN/carcass [95% CI: 0.58-0.98]) were significantly (P < 0.05) different. Salmonella was not detected on carcasses processed via the MPU. Campylobacter prevalence was not significantly (P > 0.05) different on carcasses processed by the three methods (70% on-farm, 82% USDA-IF, and 100% MPU). The mean log10Campylobacter concentrations in MPU processed carcasses (5.44 log10 CFU/carcass [95% CI: 5.24-5.63]) was significantly higher (P < 0.05) compared to on-farm (2.32 log10 CFU/carcass [95% CI: 2.06-2.80]) and USDA-IF (2.44 log10 CFU/carcass [95% CI: 2.03-2.85]). Based on the results of this baseline study, most pasture-raised broilers processed by the three methods were contaminated with Salmonella and/or Campylobacter. Further research is needed to assess other potential risk factors such as farm and regional variations that may contribute to the differences in pathogens' prevalence and concentrations.