It is beneficial to note that ATP detection systems detect one thing—ATP. Determination of whether ATP detected on a surface has come from the food or microorganisms or a combination of both cannot be deciphered by a luminometer. If it is a combination of both microorganism and food, it is impossible to know what proportion of the ATP being detected comes from the food or microorganism. Additionally, there is no correlation between RLU values and the number of microorganisms present on a surface. There is considerable variation in cellular ATP levels, particularly between species of microorganisms.
Visual inspection, microbial enumeration, and ATP detection all have a role to play when verifying cleaning and sanitation. Visual inspection allows for the quick, simple detection of heavily soiled surfaces. Microbial detection can help determine the source of product contamination, identify niches harboring specific classes of microbes missed during cleaning and sanitation, and track where microorganisms may be going next. ATP bioluminescence systems provide a rapid, actionable result if cleaning and sanitation did not successfully remove foodstuffs or microbes. The key to link all of these tools together is to analyze the data and monitor for trends to gain a true understanding of the large picture in regards to microbial control in a facility.
Lingle is senior microbiologist for global technical service at 3M Food Safety. Reach her at email@example.com.