Bioluminescence ATP monitoring as a surrogate marker for microbial load on hands and surfaces in the home

To evaluate the validity and reliability of adenosine triphosphate (ATP) monitoring as a surrogate marker for cleanliness, the kitchen table surface in 225 inner-city homes was sampled by microbiologic culture and by two types of biomass monitoring systems (HY-LiTE™ 2 ATP System and HY-RiSE Colour Hygiene Test Strip, EM Science, Gibbstown, New Jersey, USA). A randomly selected hand of the homemaker (n=225) was also cultured and sampled with the ATP monitoring system immediately after handwashing. Log microbial counts on hands ranged from 3.2 to 7.0 and from the table, 1.0 to 5.5. While the traditional ATP readings (HY-LiTE) and the color strips were significantly correlated (R=0.18, P=0.01), there was no significant correlation between the ATP monitor readings and the colony-forming units counts on either the hands (R=−0.03, P=0.62) or the table (R=0.04, P=0.58). Such biomass measurements are not a substitute for quantitation of microbial load.