Science: How ATP sanitation verification systems work

March 15, 2017

In old-timey terms, today’s modern sanitation verification systems are lickety-split.

But how exactly can a test system instantly produce accurate results showing just how clean or dirty a surface may be?

The science behind the instantly accurate systems stems from the study of fireflies and adenosine triphosphate (ATP) — a molecule that exists in every living cell.

In fireflies, two chemicals, luciferin and luciferase, combine with the ATP in their cells to produce light. This reaction, referred to as bioluminescence when it’s in nature, and chemiluminescence when incorporated into a commercial product, is the basic principal of all ATP sanitation verification systems.

The second major element of an ATP sanitation monitoring system is the use of a luminometer to measure the light produced by the reaction of ATP with luciferin and luciferase. The luminometer contains a device, either a photo-multiplier or photo-diode that detects the amount of light that is being produced from the chemiluminescent reaction occurring in the sampling devices.

When you rub the ATP sampler or swab across a surface, ATP is collected on the sampling tip. When you activate the device, typically by pushing the plunger through the cartridge, the ATP on the sampling tip mixes with luciferin and luciferase contained on a reagent pad or in a liquid mixture. Most ATP sanitation monitoring systems also feature a liquid buffering agent to counteract the effects of sanitizers.

Since the amount of luciferin and luciferase are fixed, the amount of light that is produced by the chemiluminescent reaction is directly proportional to the amount of ATP collected. So the correlation works like this: The dirtier the surface was when it was sampled, the more ATP is collected, and the more light is produced.

The luminometer reads the light, typically by averaging a series of readings over several seconds, and reports the reading in relative light units (RLUs). Most often, companies establish thresholds for pass, marginal and fail levels. These levels are typically checked by the luminometer which returns a result as pass, marginal or fail, based on the established thresholds.

Some ATP sanitation monitoring systems feature software to provide managers with a tool to analyze trends and spot potential issues. After the luminometer records the readings, the data is downloaded to a computer for storage and data analysis.


Category: Food Safety