Comparison of Three Methods for Estimating Surface Bacteria on Pork Carcasses

Abstract

Surface bacteria on skinned and scalded pork carcasses were evaluated using three different techniques: moist-swab contact (swab method), direct agar contact (Rodac method) and mylar adhesive tape (mylar method). The objective of this study was to investigate the feasibility of using one of the less expensive and quicker techniques as a tool for estimating microbial loads. Thirty-six pork carcasses were evaluated for surface contamination at four locations: ham, loin, shoulder and inside the thoracic cavity. Statistical analysis utilized the log10 of the number of observations per cm2. For all four locations evaluated, there was a difference (P<0.05) between the swab and Rodac method. A significant difference was also observed between the swab and mylar methods; however, there was no significant difference between the Rodac and the mylar methods. The correlation coefficients between methods were: swab vs. Rodac (0.43), swab vs. mylar (0.46), and Rodac vs. mylar (0.62). These data suggest that the use of mylar adhesive tape is a good alternative method for estimating surface bacterial loads.