Quantities of Adenylate Homologues (ATP+ADP+AMP) Change over Time in Prokaryotic and Eukaryotic Cells

Rapid assays for the assessment of the hygienic state of surfaces in food and medical industries include the use of technologies designed to detect the presence of the metabolite ATP. ATP is a critical metabolite and energy source for most living organisms; therefore, the presence of ATP can be an indicator of surface hygiene based on the presence of soil or food residues associated with inadequate cleaning. The concentrations of ATP vary based on an organism's metabolic state, thus potentially influencing the sensitivity of ATP-based assays. However, little has been published detailing the quantitative changes of ATP to the adenylate homologues ADP and AMP nor the quantitative and cumulative fate of these homologues over time as the metabolic state remains in flux. The objective of this study was to quantify the individual and cumulative (AXP) concentrations of these three adenylate homologues over defined time periods in selected eukaryotic tissue and prokaryotic cell cultures of significance to hygiene. ATP concentrations differed substantially across these selected variables of time and source. The 1- to 3-log reductions in ATP concentrations over time were highly affected by organism type. In general, ADP became the predominate adenylate in eukaryotic tissue, and AMP was the predominate adenylate in the prokaryotic cells at later time points in each study. Total AXP concentrations dropped in general, reflective primarily of the loss of ATP. The results of ATP-based techniques for hygiene surveillance will vary as a function of the amount of cellular material present and the metabolic state of such material.