Microbial Testing & Monitoring
Adenosine Triphosphate (ATP) is present in all organic material and is the universal unit of energy used in all living cells. ATP is produced and/or broken down in metabolic processes in all living systems. Processes such as photosynthesis in plants, muscle contraction in humans, respiration in fungi, and fermentation in yeast are all driven by ATP. Therefore, most foods and microbial cells will contain some level of naturally occurring ATP.
Luminometers (in conjunction with ATP swabs) use bioluminescence to detect residual ATP as an indicator of surface cleanliness. The presence of ATP on a surface indicates improper cleaning and the presence of contamination, including food residue, allergens and/or bacteria. This implies a potential for the surface to harbor and support bacterial growth.
ATP monitoring is used in food and beverage, healthcare, and other facilities to confirm that ATP presence is eliminated or minimized by effective sanitation procedures.
How does bioluminescence work?
Bioluminecsence is the result of a biochemical reaction and is the science behind Hygiena ATP detection tests. The reaction includes the following elements:
- Luciferase enzyme- naturally occurring in fireflies, or synthetically manufactured
- Adenosine triphosphate (ATP) - the energy molecule of all living organisms
- Oxygen- a catalyst
- Luciferin- a molecule that undergoes a chemical charge when affixed by an enzyme
ATP + Luciferin + Luciferase + O2 = Light output
The reaction occurs in two steps: The substrate combines with ATP and oxygen, which is controlled by the enzyme. The chemical energy in step 1 excites a specific molecule (the combination of Luciferin and Luciferase). The result is decay which is manifested as photon emission, or light production. The light is simply a by-product of the chemical reaction and does not depend on light.
What is an RLU?
RLU stands for Relative Light Unit and is the unit of measure used in bioluminescence. When a test swab is activated, a bioluminescent reaction occurs, generating light output. Luminometers measure and quantify that light with an RLU output. Because manufacturers use different sensor technologies and algorithms for adding up the photons, RLU measurements will vary from system to system. However, because the ATP bioluminescence reaction is linear, the more ATP present means the more light will be present.
The relationship between the amount of ATP on the sample and the RLU result reading on the luminometer is simple:
High contamination (improper cleaning) = Large amount of ATP = More light produced in reaction= High RLU reading.
The RLU reading is directly proportional to the amount of ATP collected from the sample. A high RLU reading indicates a large amount of ATP at the test location. This in turn indicates improper cleaning and the presence of contaminants.
Cleaning properly results in less ATP at the location. Less ATP results in less light output during the bioluminescent reaction and consequently, a lower RLU reading.
ATP testing is used around the globe and is a recognized tool by auditors for validating cleaning processes and complies with government and HACCP regulations.