Use of a Rapid Microbial ATP Bioluminescence Assay to Detect Contamination on Beef and Pork Carcasses

Abstract

A new microbial ATP bioluminescence assay was shown to be an accurate and rapid method to determine the levels of generic bacterial contamination on beef (n = 400 and pork (n = 320) carcasses sampled in commercial processing plants. Based on in vitro fecal dilution studies, the rapid microbial ATP (R-mATP) assay is as accurate as the standard plate count method for estimating bacteria in bovine or porcine fecal samples. The correlations (r) between the R-mATP assay and the standard aerobic plate count for beef and pork carcasses sampled in commercial processing were 0.91 and 0.93, respectively. A segmented-model statistical approach to determine the lower limits of assay sensitivity was developed. By using this model to analyze the in-plant data, the R-mATP test responded in a linear fashion to levels of microbial contamination of > log10 2.0 aerobic CFU/cm2 on beef carcasses and of > log10 3.2 aerobic CFU/cm2 for pork carcasses. The R-mATP assay requires approximately 5 min to complete, including sampling. Given the rapidity and accuracy of the assay, processors interested in monitoring critical control points in the slaughter process could potentially use the R-mATP assay to monitor microbiological prevention and intervention procedures for minimizing carcass contamination.