ATP or Adenosine Triphosphate is the main energy transfer molecule present in all living (and once living) biological cells including animal, plant, bacterial, yeast, and mold cells. Measuring the presence of ATP can help determine the amount of invisible organic matter remaining after cleaning, and hence the likelihood that the cleaned surface supports or can support the growth of microbes.
ATP measurement in the field is enabled by a compact handheld device called an ATP meter. The advantage of an ATP meter over lab-based methods is that it provides results in real time (i.e., seconds instead of days) and at a low cost. This enables immediate feedback and quick corrective action as needed.