Submitted to: Food Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/16/2013
Publication Date: 11/1/2013
Citation: Trimble, L.M., Alali, W.Q., Gibson, K., Ricke, S.C., Crandall, P., Jaroni, D., Berrang, M.E. 2013. Salmonella and Campylobacter prevalence and concentration on pasture-raised broilers processed on-farm, in a Mobile Processing Unit, and at small USDA-inspected facilities. Food Control. 34(1):177-182. Interpretive Summary: There is increasing consumer interest in local and all natural foods including broiler meat. Small scale producers that raise broiler chickens in a pasture or free range environment for the local market do not often have commercial slaughter and processing facilities available for their use. Such producers may process their own birds on the farm, truck them long distance to small USDA inspected custom processing facility or use a cooperatively owned mobile processing unit which travels from farm to farm on a trailer. It is unclear how these three different processing options affect the presence of human pathogens such as Campylobacter and Salmonella on processed broiler carcasses. Broiler carcasses from small farms raising pastured broiler for the local market were collected following processing: on-farm, in a distant small USDA inspected plant and in a mobile processing unit. Carcasses were cultured for Salmonella and Campylobacter. Campylobacter was detected on carcasses processed by all three methods; the numbers of Campylobacter was highest on carcasses processed in the mobile processing unit. Salmonella was detected most often on carcasses processed on farm, substantially less often on carcasses processed in the small processing plant and was not detected in any of the carcasses processed in the mobile unit. These results show that most pasture raised broilers can be expected to be contaminated with Salmonella and/or Campylobacter. These results are useful to small producers as they make decisions relative to processing options. More research will be required to determine other risk factors and regional or geographic considerations.
Technical Abstract: The small-scale, pasture-raised poultry production model is a growing niche in the locally grown food movement. There is limited research that focuses on the food safety of small-scale broiler processing methods. 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 (USDA)-Inspected custom slaughter facility (U-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. Salmonella and Campylobacter concentrations in 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. 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. 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 log10 Campylobacter concentrations in MPU processed carcasses (5.44 CFU/carcass [95% CI: 5.24-5.63]) was significantly higher (P < 0.05) compared to on-farm (2.32 CFU/carcass [95% CI: 2.06-2.80]) and USDA-IF (2.44 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 with the exception of MPU carcasses on which Salmonella was not detected. Further research is needed to assess other potential risk factors such as farm and regional differences.