Adenosine triphosphate (ATP) is found in all living cells. It is the universal agent used for the transfer of energy. ATP is found in cells of plant and animal origin as well as in live bacterial cells. ATP is present at a concentration of 10-18 to 10-17 mole/bacterial cells and disappears within 2 h after bacterial death. 18

ATP tests can be used to rapidly evaluate the effectiveness of cleaning and sanitation in a food-processing plant. The ATP present may be due to food residues or to the presence of viable bacteria, but in either case, the presence of ATP on food-processing surfaces after cleaning and sanitizing is an indication of poor hygiene.