USE OF A RAPID MICROBIAL ATP BIOLUMINESCENCE ASSAY TO DETECT CONTAMINATION ON BEEF AND PORK CARCASSES

A new microbial ATP bioluminescence assay was shown to be an accurate and rapid method to determine the levels of generic bacterial contamin ation on beef (n = 400) and pork (n = 320) carcasses sampled in commer cial processing plants. Based on in vitro fecal dilution studies, the rapid microbial ATP (R-mATP) assay is as accurate as the standard plat e count method for estimating bacteria in bovine or porcine fecal samp les. The correlations (r) between the R-mATP assay and the standard ae robic plate count for beef and pork carcasses sampled in commercial pr ocessing were 0.91 and 0.93, respectively. A segmented-model statistic al approach to determine the lower limits of assay sensitivity was dev eloped. By using this model to analyze the in-plant data, the R-mATP t est responded in a linear fashion to levels of microbial contamination of > log(10) 2.0 aerobic CFU/cm(2) on beef carcasses and of > log(10) 3.2 aerobic CFU/cm(2) for pork carcasses. The R-mATP assay requires a pproximately 5 min to complete, including sampling. Given the rapidity and accuracy of the assay, processors interested in monitoring critic al control points in the slaughter process could potentially use the R -mATP assay to monitor microbiological prevention and intervention pro cedures for minimizing carcass contamination.