Using ATP Bacteria Meters to Measure Cleanliness

    With COVID-19 making headlines around the world, many businesses are looking for new ways to keep their premises, visitors, and employees safe from biological hazards such as viruses and mold. ATP (Adenosine triphosphate) testing can be utilized to protect against unseen biohazards by identifying the location of unwanted biological material in almost any environment. But what is ATP testing, how does it work, and could it be useful for your business? We’ve got all the answers to your ATP testing questions.

    What is ATP testing?

    ATP detection tools test for a molecule called Adenosine triphosphate, or ATP. This molecule is only found in living cells, where it functions to convert the energy the cell needs to work, and is common to all known forms of life. That means if it’s alive, it’s got ATP, and an ATP test can be used to find places where fungi, mold, and bacteria are thriving before the evidence is visible to the naked eye. This makes ATP testing a powerful tool for cleaning crews and business owners alike.

    The detection method for ATP relies on triggering and measuring bioluminescence (biological light) using an ATP luminometer. ATP reacts with the enzyme luciferase — the chemical that makes fireflies glow — and the amount of light it produces is directly proportional to the amount of ATP in the sample. By measuring the light using an ATP bioluminescence assay kit, we can calculate the amount of biological material in any given area.

    How does it work?

    ATP testing kits come in two parts: a handheld assay reader, and a disposable swab with a reagent solution that usually looks something like a pen. The tester removes the swab wand from the solution and smears it across the testing area to collect any microbes that may be present. The swab is then reinserted into the reagent solution and the tube is connected to the assay reader. The reader then performs the bioluminescence test with luciferase and measures the results. Most readers can display the results directly, as well as save digital records of the readings they produce. The majority of ATP tests take about 15 seconds to read and analyze the sample material.

    There are many uses for ATP tests in all kinds of commercial settings, including:

    • Sanitation: Testing drinking water for potability
    • Industrial cleaning: Guiding biocide dosages
    • Brewing: Monitoring large-scale fermentation
    • Farming: Assessing soil activity
    • Food preparation: Measuring surface cleanliness
    • Medical: Ensuring proper sanitization
    • Janitorial: Surface testing in schools, colleges, office buildings, and more

    In many environments, the presence of microscopic living cells is a warning sign that additional cleaning and sanitization protocols are required. Most microbes that are harmful to humans, causing anything from allergy attacks to serious sickness and even death, are invisible to the naked eye until an infestation is out of control. ATP testing lets us “see” these microbes before they reach dangerous levels, and this makes ATP testing an invaluable resource across multiple industries and commercial premises.

    What are the best areas to test with an ATP meter?

    In order to get the best results from ATP testing, it’s important to identify the areas that are (a) most likely to be contaminated, and (b) most likely to be overlooked by routine cleaning. Possible locations for significant ATP test results include:

    • Switch plates, elevator buttons, and door handles
    • Food contact surfaces, including sinks, cutting boards, and cutlery
    • Computer keyboards, mice, and desk surfaces
    • Chair handles, waiting room magazines, and reception counters
    • Shower stalls, exercise equipment, and bathroom faucets

    Any high-touch areas that are frequently omitted from usual cleaning routines are good potential sources of unwanted biological material. With the COVID-19 outbreak, and during flu season, it’s advisable to review your business premises and identify as many at risk areas as possible and implement cleaning protocols that are designed to deliberately target these areas. Doing so will minimize harmful microbes in the environment and prevent outbreaks of sickness among staff and visitors.

      How reliable is ATP meter testing?

      Although ATP testing is incredibly effective, it does have some downsides. Firstly, because ATP is present in every living cell, a positive test cannot identify any particular bacteria or organism. As such, its primary use is for testing environments that either should or should not be sterile, in which case any result is significant, or for determining the total quantity of a known organic substance.

      When using ATP testing on water samples containing microorganisms, it’s also important to consider that there are two types of ATP that can both be recorded on tests. These are intracellular ATP (that is ATP found within living cells) and extracellular ATP (that has been released from cells due to stress or decay). A water sample that produces a positive result for intracellular ATP is more likely to be unfit for human consumption than a sample that tests positive for extracellular ATP from dead organisms, so determining which type of ATP is in a sample is an important factor in accurate testing.

      First generation ATP tests are used when looking for a simple yes/no to the presence of biological material within a sample. Second generation tests are designed specifically for water and industrial applications where samples may contain a variety of contaminants, not all of which are indicative of a problem.

      In lab studies, ATP bacteria meters were also susceptible to interference by disinfectant solutions, which can dilute ATP concentrations or otherwise distort results. For the most accurate readings, best practice is to swab an area both before and after cleaning and compare the results.

      ATP meter testing for viruses

      Another important exception to ATP testing’s effectiveness is viral testing. Viruses aren’t living cells, and therefore typically don’t have ATP and don’t show up on ATP tests. For similar reasons, ATP tests cannot consistently detect bacterial spores.

      That means that ATP tests alone cannot confirm the presence or absence of all viruses and other microorganisms. However ATP testing is a fast, reliable way to confirm the presence or absence of biological matter in a sample area, which is a good indicator of general cleanliness and hygiene levels. Used as part of an overall cleaning and sanitization strategy, ATP testing provides important insight into the prevalence of contaminants that cannot be seen by the naked eye.

      ATP testing standards

      There are a number of variables to consider when determining a standard for ATP testing, such as the size of the area being tested and the distribution of potential contaminants. In a medical facility, for example, ATP testing might form part of the post-cleaning checks to confirm if all surfaces have been thoroughly cleaned, but results will always be limited to the area that was swabbed. If part of a surface was overlooked during cleaning, or contaminants are unevenly distributed, ATP swab results can paint a false view of the true state of cleanliness. That’s why it’s important to put in place protocols to produce the most accurate results possible.

      Sample size and contaminant saturation levels have been open to debate by the scientific community. The initial guideline was a 10 x 10 cm (100cm2) area with a target level of <500 Relative Light Units (RLU). Further tests reduced the target RLU to 250, then 100. The most recent studies, using the Hygiena brand ATP monitor, suggest sampling a 2 x 5 cm (10cm2) area with a target of 100 RLU.

      It should be noted, however, that although all ATP luminometers produce results in RLU, each brand uses its own scale and guidelines for how each RLU is determined, meaning 100 RLU on a Hygiena model is different to 100 RLU on any other meter. Therefore testers should always follow the parameters determined by the manufacturer of the ATP testing machine they are using.

      Cleanliness testing using ATP bioluminescence: Advantages and Disadvantages

      Can detect contaminants invisible to the naked eye.
      Cannot detect most viruses or bacterial spores.
      Fast and effective way of checking cleanliness and sanitation.
      Cannot identify the source of contamination.
      Does not produce hazardous byproducts or residue.
      Only provides results accurate for the specific area being tested.
      Universal test for almost all organic contaminants, whatever the source.
      Can produce false results when only a small amount of contaminants are detected.
      No specialist scientific training is required to use the meter or interpret results.
      Results can be contaminated by user error — e.g. getting skin cells on the swab.

      ATP testing by industry

      ATP testing has a variety of specialized uses, such as testing water contamination, soil flora, and fermentation processes. However this method of testing also has more general purpose uses within various industries that need to confirm they are maintaining cleaned and sanitized environments.

      ATP testing for operating rooms

      One of the most obvious locations where ATP testing is invaluable is in medical facilities such as operating theaters. ATP testing cannot confirm sterility — that requires a microbiology test to identify any and all contaminants, including those not detected by ATP tests — but they are a fast and effective means of checking if an area is likely to have been contaminated. Because ATP tests react to almost every living organism, they provide a convenient universal check for most contaminants.

      For optimal results, ATP tests should be carried out after cleaning, but before sanitizing. This is because most sanitizers require clean surfaces, free from biofilms or biological residue, in order to work most effectively. ATP test results can highlight areas where cleaning has been insufficient and thus provide better sanitization results as part of a wider cleaning and sanitizing regimen.

      Surface hygiene monitoring

      It isn’t only operating rooms where it’s important to have clean surfaces. Food preparation and handling areas, from meat packing plants to industrial or professional kitchens, are also good candidates for ATP monitoring. It’s important to conduct surface testing on any areas that come into contact with food, as well as indirect contact areas such as splash zones, filter heads, and drainage channels.

      ATP is present in many food items at varying levels, because food is derived from organic (living) sources. However the more highly processed a food is, the less ATP it contains. Cooking oil, for instance, has very little ATP and even a significant oil spill will not register highly using an ATP luminometer.

      Monitoring ATP levels alone also doesn’t distinguish between relatively harmless food waste, such as a few crumbs overlooked on a surface, and more damaging bacterial or fungal growth. Universal testing methods that don’t determine the source of the positive result, such as ATP tests, also have limited effectiveness at allergen monitoring. As such, ATP testing in food handling and preparation areas should be just one method of ensuring a clean and safe environment.

      ATP monitoring for cleaning

      When it comes to all-purpose commercial and industrial cleaning, the peace of mind provided by an ATP test can be hard to beat. ATP tests are a cost-effective way of conducting frequent, wide-scale testing of schools, offices, colleges, and other workplaces. With more focus than ever being placed on cleanliness in light of the COVID-19 pandemic, building managers and janitors can benefit from adding a rapid-result bacteria testing kit to their regular cleaning and maintenance regimen.

      Sanitation and cleaning companies

      Professional commercial cleaning companies are increasingly using ATP testing as part of their overall service, both to determine areas in need of extra attention, and to demonstrate the effectiveness of their service to clients. When you hire professional cleaners for your business or commercial premises, you want to know they’re doing a thorough job. By providing ATP test results, business owners and site managers can be assured that cleaning has been completed to a high standard.

      Can ATP tests be used for COVID-19?

      SARS-Cov-2, the virus that causes COVID-19, cannot be detected using an ATP kit because viruses do not typically contain ATP. Unlike most other microbes, viruses are not technically living organisms in the sense that bacteria, fungi, and even plants, animals, and humans are. While not dead — viruses still respond to their environment — neither are they alive.

      Viruses aren’t made of cells, but of a single particle known as a virion that is basically just a bundle of genes inside a protein shell called a capsid. Some viruses, including SARS-CoV-2, also have an extra fatty membrane surrounding the capsid. That’s why household soap is so effective against the novel coronavirus, because soap destroys the fatty membrane that protects the virus inside.

      Because viruses don’t have cells, they don’t have nuclei, organelles, or cytoplasm, and therefore have no need for ATP, which is the molecule that enables cells to transfer energy. That’s why viruses aren’t detected by ATP meters, because they derive all of their energy from parasitizing their hosts’ cells.

      For this reason, ATP testing is not a good indicator of the presence or absence of the novel coronavirus. It is, however, extremely useful for judging the effectiveness of general cleaning conducted in an area. If an environment is clean of biological contaminants, it is likely to have been cleaned sufficiently to combat viruses as well. For more information on how to clean to effectively combat viruses and other microbes, check out our handy guide.

      What can an ATP test be used to detect?
      Food waste
      SARS-CoV-2 / COVID-19 coronavirus
      Fungal growth
      Flu virus / Rhinovirus (common cold)
      Bacteria microbes
      Bacteria spores
      Processed food waste

      In conclusion…

      ATP testing is an important step in understanding the true level of cleanliness in almost any environment. Because ATP is present in all living cells, bioluminescent testing for ATP can identify all manner of microbial dirt and bacteria, from food waste to biofilms and other potential hazards.

      There are limits to ATP’s effectiveness — it cannot detect viruses, and it cannot tell the tester what materials it has detected. For those reasons, ATP testing alone is insufficient to meet the requirements for sterile environments such as medical facilities, veterinary surgeries, and some food processing areas. However ATP testing is a vital indicator of the presence or absence of contaminants in an environment.

      For offices, colleges, the hospitality industry, gyms, commercial kitchens, and more, ATP testing is a fast, cost-effective way of gauging the extent and effectiveness of routine cleaning regimens and identifying problem areas where otherwise bacteria would flourish undetected. ATP tests are simple to administer and understand, can deliver results in seconds, and provide peace of mind for business owners, property managers, workers, and visitors. A clean workplace makes for a happy and healthy workforce, reducing absenteeism and saving costs on lost productivity and sick days.

      Cleaning and sanitizing services can also benefit by offering ATP testing as standard, increasing client confidence with proof of the results of their work. When hiring any cleaners, it can be hard to trust that a job has been done thoroughly. ATP testing eliminates that worry by providing real evidence that a property has been thoroughly cleaned and sanitized.