Abstract: A bioluminescence method combined with adenosine triphosphate (ATP) amplification through regeneration from pyrophosphate (PPi) was developed to detect bacteria in dairy products. Experimental conditions were optimized by?one-factor-at-a-time method. The sensitivity, precision and accuracy of this method were studied. The results showed that adenosine phosphosulfate (APS) concentration of 10 μmol/L, ATP sulfurylase (ATPS) activity of 0.15 U/mL and pH of 7.8 were found to be the optimum conditions. The method showed a good linearity within the range of 102–107 CFU/mL with lowest limits of detection (LODs) of 10?17 mol/mL, 102 CFU/mL and 102 CFU/mL for ATP, Escherichia coli and Pseudomonas aeruginosa, respectively. The recoveries of E. coli in dairy at three spiked levels ranged from 81.33% to 97.78%, with coefficients of variation between 14.24% and 22.17%. Good correlation between this method and the standard plate count method was obtained using spiked dairy samples. The proposed method is fast, simple, sensitive, stable, and thus suited for fast detection of bacteria in dairy products.

Key words: ATP amplification, bioluminescence assay, fast detection, dairy products