Your Guide to Adenosine Triphosphate (ATP) Testing

Everyday, the high-risk decision to start food production needs to be made. So, how do you know if surfaces are clean and safe for production?

Cleaning and sanitation programs are needed to prevent pathogen and spoilage microorganism as well as allergens in food production facilities. Adenosine Triphosphate (ATP) testing is a critical step to assess the effectiveness of your cleaning and sanitation programs quickly and easily to ensure production can begin. Hygiene monitoring, like ATP testing, is essential to support the programs that help identify the high-risk sites for pathogens and spoilage microorganisms allowing you to have peace of mind when making and managing risk.

What is Adenosine Triphosphate?

ATP is a chemical found in every cell of living organisms. It stores energy and gives cells energy they need to function. As well as being existing in living cells, it is present in residues from organic sources such as:

• Food debris remaining on a surface after cleaning
• Biofilms produced by bacteria
• Surfaces touched by operators

How do you measure ATP?

ATP testing utilizes the energy present in the ATP molecule along with an enzyme complex known as Luciferin- Luciferase to produce light. In the bioluminescence reaction, luciferase utilizes ATP to catalyze the oxidation of luciferin to oxyluciferin, yielding light.

Putting this into action, ATP testing is conducted using ATP swabs and a Luminometer to receive a Relative Light Units (RLU) measurement. Upon activation of the test, the chemical reacts with the sample collected on the swab to produce the light. The amount of the light produced can be correlated to the amount of ATP present and therefore the amount of ATP-containing organic matter present. If organic matter is present it will result in higher RLUs. It is important to note, readings from different manufacturers are not interchangeable. For example, a reading of 10 RLU from one manufacturer may be equivalent to 50 RLU for another manufacturer, so pass and fail levels must be independently determined for each system.

Once you receive all the data, how do you analyze it to put it into action? Regular ATP testing generates a large volume of quantitative data, which makes it easier to proactively identify trends in high-volume testing environments before you see failures.

Why is proactive cleaning and sanitation important?

A surface may look clean, but it doesn't mean it is. Organic matter on a surface can act as a food source for microorganisms. Removing this organic matter reduces the chance for bacteria and mold to spread, therefore reducing the microbial risk within the processing environment.

Cleaning practices can remove debris (product residue, microbial contamination, biofilms, chemical/biological material), and can also improve efficacy of sanitizers to inactive contaminants as well. Further improving the overall sanitary status of the facility and reducing risk.

ATP testing can provide a measurable and objective assessment of the cleanliness of equipment and surfaces prior to food processing or preparation. Many processing facilities measure the effectiveness of their cleaning practices to ensure production can begin.

How does ATP testing compare to other verification methods?

As mentioned above, processing facilities need to quickly determine if cleaning has been effective so food production can begin. Visual inspection, ATP testing and microbiological testing have different roles in the cleaning and sanitation verification and risk management processes.

Visual inspection - can quickly provide a big-picture view around the effectiveness of cleaning. This method is limited because trace levels of contamination cannot be seen by the naked eye and surfaces on product equipment that are contaminated aren't always visible. Visual inspection can be used prior to ATP testing but should not be a substitute for it.

Microbiological testing - cannot provide immediate results on the manufacturing floor, because testing needs to be conducted and analyzed at another location. While microbiological testing can help identify specific organisms, during the testing period, it may hold up food production, which could result in reduced shelf life and sales, or potentially warrant a recall if contaminated food is released.

Adenosine Triphosphate testing - is highly efficient because it quickly and easily provides results. It will either allow production to begin or show that recleaning and retesting are necessary to reduce contamination before food production may begin.

When do you test for ATP?

Best practice is pre-operational in between the cleaning and sanitation steps. Sanitizer don't work on dirty surfaces, so swabbing after cleaning reduces the risk of sanitizer interference. If required, swabbing can be performed after the sanitation step. Verification and validation is highly recommended here, ask supplier regarding interference of residual sanitizers. When verifying the sanitizers it will not interfere with the ATP detection. You can swab a surface that has been treated with diluted sanitizer and use an ATP positive control to ensure there is no quenching, and swab as surface that has been treated with diluted sanitizer and to determine if the result is not artificially high.

Why do you need an ATP sampling program?

Let's break down an environmental monitoring program into three steps. First, is the initial program to validate the cleaning process. This is followed by a program for routine verification of the process and finally ongoing review and adjustments to the program.

The initial validation program will typically involve testing more often and has more test points to develop baseline levels for the cleaning process. Revalidation should be done when changes are made to the facility, such as new cleaning chemicals or processes, new equipment is used, or new products are manufactured.

The ongoing verification program is then generally conducted using fewer test points. However, the data collected should be routinely reviewed and analyzed to determine if there are any trends or areas of concern, and to confirm that the program is working or if adjustments need to be made.

Where to do the sampling and testing?

Sampling site selection should start by mapping out an overview of the facility and the production process. This involves separating the facilities into several zones based on the microbial risk to the product. You can start by addressing these four risk-based approach factors:

1. Proximity to food
2. Potential for cross-contamination
3. Accessibility for cleaning and testing
4. Equipment age, substrate and condition of surface

When zones have been established, test points can be determined based on where the assessment of cleanliness and control of risk are needed. It should be noted that the ATP test points may differ from microbiological sampling sites.

Based on these principles, ATP testing is typically directed towards Zone 1 (product or packaging contact) test points. With the lowered chance of direct risks at these points, the primary focus should be to control indirect risks such as unclean surfaces that can lead to direct risks or impact product quality.

In larger food production facilities, the equipment is likely to be more complex and involve both manual and clean-in-place systems. In these facilities, a comprehensive program involving indicator and pathogen testing should also be established. In smaller facilities such as catering kitchens, the ability to conduct microbiological testing may be limited. In these cases, ATP testing may be increasingly used in Zone 2, indirect food contact surfaces which could mean a higher risk for cross contamination.

As discussed, one of the key benefits of ATP testing is the speed at which results are available, therefore allowing immediate corrections to be taken. If there is a failing result, it should be documented as part of the quality system, and corrective actions should be taken to prevent a recurrence.

In the case of hygiene monitoring, a failed test outcome will typically result in recleaning and retesting until there is a passing result. Sometimes, a caution range may be implemented in the system, so the corrective action may not warrant immediate action, but instead a more thorough cleaning and/or increased scrutiny before the next production run. Repeated fail or caution results should be investigated as a priority by those on site who have knowledge of the process, and appropriate preventive actions should be implemented. Along with speed and sensitivity, a key benefit of adenosine triphosphate (ATP) testing is the ability to trend and analyze the generated data over time. This provides a better understanding and ultimately control of the facility's hygiene and production processes.

You have a lot on the line when it comes to hygiene monitoring testing, so accurate information is critical. Keep things moving along with a monitoring and management system that is designed to give your peace of mind with patented technology and design.

Learn more about the Neogen® Clean-Trace® Hygiene Monitoring and Management System.

Related Content:

Webinar - ATP Testing Part of an Integrated Environmental Monitoring Program

Handbook - Environmental Monitoring

Article - ABC's of ATP

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