Environmental monitoring with ATP testing

Workers in plant_blogEnvironmental monitoring is becoming increasingly important as FSMA finalization and compliance looms closer. One critical aspect of this is testing the cleanliness of the plant environment, thereby assessing the effectiveness of the facility’s cleaning processes. One of the most common tests for cleanliness is that of Adenosine triphosphate (ATP). ATP is a molecule found in all living cells; thus, in and of itself, ATP is not a hazardous contaminant, rather detection of its presence after equipment has been cleaned is an indicator that food, bacteria, or other organisms have been left behind and the cleaning process was not sufficient.

As such, ATP hygiene monitoring systems have become a standard used for measuring the effectiveness of cleaning efforts in the food production industry, said Neogen Market Development Manager Jim Topper. Testing for its presence after a cleaning program has been conducted provides an ideal indicator of the amount of cellular-based, organic residue left on a surface which could potentially contaminate the next run.

An Indicator Test

ATP testing is not new, it has been around for more than 20 years. It also is important to note that it is simply an indicator test; it does not specify the type of organism detected, nor does it mean that a pathogen or allergen is present. You could have a positive ATP test and negative micro test on the same surface, said Hygiena Marketing Manager Lauren Roady. However, she added, “Any food residue is a breeding ground for bacteria; what you’re looking for is absence of food residue, protein, etc.”

“You cannot test quality and safety into a product, but you can test quality and safety into an environment,” Roady said. “You can completely control the cleanliness of the environment to ensure a safe product.” Thus, the purpose of ATP testing is to verify that the plant environment and food-contact surfaces are cleaned to remove all residues and potential bacteria breeding grounds.

Such verification is exactly what facilities will need to comply with new FSMA rules. Roady does not expect FSMA to bring a lot of change in environmental monitoring for facilities that have implemented HACCP. But the greatest difference will be the need for verification and validation of preventive controls, including cleaning and sanitation. “It will be more of a formalization,” she said. “That’s where ATP testing and environmental monitoring come in.”

Topper also expects that compliance with FSMA will impact plants’ validation and documentation of their practices. “The implications that I am seeing are about documentation,” he said. Facilities will have to do a better job of documenting and rationalizing their processes and validating their systems.

A Preventive Action

FSMA’s focus on prevention also is increasing the importance of ATP testing as it provides plant personnel with an indication that corrective action is needed to prevent potential contamination. “ATP provides an indication of cleanliness. It is directly an indicator of the ability of the process used to remove bacteria,” Topper said.

A micro test, on the other hand, would show that a pathogen or allergen is present, thus reactive action would need to be taken, such as stopping production, recalling food, etc. A thorough environmental monitoring program would, thus, consist of both ATP and micro testing, with ATP testing to verify the effectiveness of cleaning and micro testing to validate the absence of adulterants.

ATP testing is also beneficial as an indicator test because of time to results and cost-effectiveness. ATP tests can provide results in less than a minute, while micro tests generally require hours or days for enrichment and results. ATP tests can be conducted by plant personnel on the line costing a few dollars per test; micro tests are typcially more and must be conducted in a secure laboratory, with many plants opting to send out this testing to third-party labs, further increasing costs.

Trend Analysis

Both Topper and Roady noted that the real key to—and benefit of—ATP indicator testing is trend analysis. There is no absolute number that indicates a “good” test result, Topper said. “A score is not necessarily good or bad, it is better or worse.” Thus, each facility needs to use the testing to set a benchmark, then gauge progress or relapse from that. When a facility first begins ATP testing and/or its analysis, it is likely to see high numbers with a lot of variation, but as analysis continues and corrections are made, the numbers should come down, and there should be less variation. “This means that you are cleaning better and with more consistency,” he said.

At that point, Topper added, you may set a lower threshold because you are getting better, and you now have a “new normal.” And that is as it should be. “You should be continually evolving and your processes getting better.”

The ability to analyze trends and make improvements also has become simpler with the continuing evolution of ATP systems. Tests are available that are more sensitive, but no more expensive, and the software through which results can be analyzed is becoming more robust, Roady said. Test data can be compiled and trended by specific statistics, such as time, location, and personnel, to show where improvements or training may be needed. “It provides more power to be more proactive,” she said.

However, a specific ATP standard will come down to the individual plant and the product being produced, Roady said. For example, if you are producing a ready-to-eat food, your standards should be fairly strict; if your product is low risk, they may be less stringent.

Either way, though, if you start to notice an upward trend in the numbers, it means that something is changing for the worse, she said. It could be that equipment is wearing down, the sanitation program has changed, different cleaning tools are being used, etc. The cause needs to be investigated and corrected until numbers come back in alignment with an acceptable standard. Additionally, she said, “A positive ATP test usually incites corrective action, such as re-cleaning the equipment, then retesting for a negative before production can restart.”

Topper voiced similar sentiments, stating, “The implication from a fail is that you need to re-clean. That’s the standard reaction.” However, he added, “If I see numbers creeping up, it may also mean that the equipment is becoming harder to clean.” At that point, you should either take the equipment out of service or make a change to fix the issue. “Ideally, you always want to see your numbers coming down,” he said.

While ATP indicator testing is a significant part of an environmental monitoring program, both Roady and Topper cautioned that it is just one part of the program. “Sanitation monitoring is just one leg of a three-legged stool,” Topper said. Robust monitoring also includes allergen testing and pathogen screening. “You may have a low ATP number, but if some of those are pathogenic, you have an issue.”

This article was originally published in Quality Assurance and Food Quality Magazine on March 31, 2015 and was written by Lisa Lupo. To read the original article, click here

For more information on Neogen’s AccuPoint® ATP Sanitation Monitoring System, click here.

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