The comparison of four bioluminometers and their swab kits for instant hygiene monitoring and detection of microorganisms in the brewery

Four luminometers and their swab units were evaluated for detecting ATP by surface swabbing. Testing included pipetting known quantities of ATP directly onto the swabs; pipetting known levels of bacteria and yeast directly onto the swabs and swabbing samples of bacteria and yeast from a surface. None of these instruments and swab detection kits provided consistent, reproducible detection of ATP standards or ATP from microorganisms even at high concentrations. All of the swab kits/instruments showed poor linearity in measuring known quantities of ATP and showed high variability in ATP readings with replicate swabs containing identical concentrations of microorganisms. Since good linearity and reproducibility could be obtained using a liquid sample assay of ATP standards without swabs, it is suggested that the swab method itself may be unreliable. ATP may not be effectively released from microorganisms on swabs; ATP may adsorb to the swab interfering with detection and/or the swab might block light transmission. Swabs of bacterial/yeast suspensions dried on a sterilized surface, provided the most inconsistent ATP readings and lacked linearity, A reason for the poor detection of microbial ATP by surface swabbing could be the inability to pick up microorganisms effectively.