An Evaluation of Sampling Methods for the Detection of Escherichia coli and Salmonella on Turkey Carcasses
Abstract:The efficacy of rinse, excision, and swab methods for the microbiological analysis of prechill turkey carcasses was investigated. Aerobic plate counts from a 50-cm2 area of the breast sampled by excision and by swabbing were compared. Escherichia coli and Salmonella recoveries were determined from turkeys sampled by a carcass rinse (CR), a modified rinse with the carcass supported in a swing (MCR), a two-site swab of 50 cm2 at the back and thigh (2S), a one-site swab of 50 cm2 beneath the wing (1S), a whole-carcass swab of the inner and outer carcass surface (WS), and excision of 25 g of neck skin tissue (NE). The effect of diluent volume (25, 50, and 100 ml) on E. coli counts from swab samples was also assessed. The aerobic plate count from breast tissue sampled by excision was greater than that by swabbing (P < 0.05). E. coli recoveries by the MCR method were similar to those by CR. E. coli counts from 1S and WS samples were higher when swabs were stomached in 50 rather than 25 ml of diluent (P < 0.05). For swabs stomached in 50 ml of diluent, E. coli recoveries by the MCR, 2S, 1S, and WS methods were similar. For swabs stomached in 50 ml of diluent, Salmonella recoveries by the WS and MCR methods were higher than those by the 2S and 1S methods. Excision was more effective than swabbing for obtaining total bacterial counts from reduced turkey carcass areas. Whole-carcass sampling by rinsing or swabbing is necessary for optimum Salmonella recovery. Sampling a reduced area of the carcass is sufficient for E. coli analysis.
Document Type: Research Article
Affiliations: Great Plains Institute of Food Safety, Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, North Dakota 58105, USA