Bioluminescent ATP Assay for Rapid Estimation of Microbial Numbers in Fresh Meat

The utility of a bioluminescence adenosine triphosphate (ATP) procedure to estimate bacterial levels in fresh meat products was investigated. A double filtration (DF) sampling procedure was used. In this system two filters were fitted in tandem. A prefilter was used to trap food particles which contained contaminating ATP while the second filter retained the microbial population. The second filter was treated with an enzyme reagent to hydrolyze nonmicrobial ATP that was present on the bacterial filter. Using standard curves, that related bacterial ATP (B-ATP) and plate counts, the bacterial ATP levels in fresh beef and chicken samples were transformed into estimated bacterial levels in the products. The ATP procedure was able to predict bacterial levels within +/- 0.5 log₁₀ of the actual plate count for greater than 90% of the fresh beef and chicken samples tested. Mean femtogram (fg) ATP/CFU levels in fresh beef and chicken mixed bacterial flora were 0.88 and 0.94, respectively. Minimal sensitivity of the double filtration/enzyme method was approximately 5 × 10⁴ CFU/g of meat sample.