Environmental Monitoring Case Study: ATP & Microbial Testing

Enhancing Food Safety and Quality Through a Combined Hygiene Monitoring Approach 

Food manufacturing facilities, regardless of size or product produced, must comply with established regulations for food safety and quality. Regional and local regulations can require control of biological, physical, and chemical hazards to prevent product contamination caused in production environments. Meeting these requirements can be accomplished through a robust environmental monitoring program (EMP) that uses both adenosine triphosphate (ATP) bioluminescence testing and microbiological indicator testing to validate the effectiveness of these cleaning and sanitation procedures.  

How ATP and Microbiology Testing Can Work Together 

ATP bioluminescence testing is a widely accepted method of hygiene monitoring that can indicate in real time whether cleaning and sanitation have been effective. In addition, microbiological indicator testing provides results to verify sanitation status. Using ATP bioluminescence testing and microbiological indicator testing, in combination, can provide an assessment of cleaning and sanitation operations. However, to use these tools most effectively, a systematic framework for the introduction and application of these tools is also needed. The real power comes in combining the two of them, as this creates a multi-layered verification system; ATP bioluminescence offers immediate feedback on surface cleanliness, while microbiological testing provides a crucial validation of the long-term effectiveness of sanitation protocols. 

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A Real-Life Environmental Monitoring Application 

However, simply having these tools isn’t always enough. You need a strategy to use them effectively. That’s where an environmental monitoring plan framework comes in. To demonstrate the power of this combined approach, Cornell University’s Department of Food Science and Neogen Food Safety collaborated for a multiphase study in a real-world ready-to-eat (RTE) food manufacturing facility. With the goal to see how integrating ATP bioluminescence and microbiological indicator testing within a structured framework could impact cleaning, sanitation, and ultimately, product quality. 

Multi-Phase Study Methodology in a Food Manufacturing Facility

As the three-phase study began, 30 sites were identified for ATP and microbiological testing, based on relative difficulty of cleaning and sanitation, with a preference for sites considered harder to clean.  

During Phase 1, the team verified cleaning and sanitation procedures and established baseline result ATP testing of the 30 sites per day for three weeks using the Neogen® Clean-Trace® Hygiene Monitoring and Management System. Microbiological testing of the environment was performed, in parallel, for yeast and molds, lactic acid bacteria, and aerobic microorganisms. Environmental samples were collected from adjacent surfaces using Neogen® Quick Swabs and tested using Neogen® Petrifilm® Rapid Yeast and Mold Count Plates, Neogen Petrifilm Lactic Acid Bacteria Count Plates and Neogen Petrifilm Rapid Aerobic Count Plates.  

During Phase 2, results from Phase 1 were used to identify and target sites that needed enhanced cleaning. Enhanced cleaning included increased time spent cleaning and some disassembly of equipment to access hard-to-clean areas. ATP and microbiological testing were maintained for 30 sites per day for six weeks.

In Phase 3, the Neogen Clean-Trace Hygiene Monitoring Software was used to randomize sites and optimize sampling. ATP testing and microbiological testing were conducted on 18, rather than 30, sites per day for 16 weeks, while maintaining the modified cleaning practices. In Phases 1 and 3, food product samples were collected during production and evaluated using Neogen Petrifilm Rapid Yeast and Mold Count Plates, Neogen Petrifilm Lactic Acid Bacteria Count Plates, and Neogen Petrifilm Rapid Aerobic Count Plates to determine the impact of targeted cleaning on the microbial quality of products.  

Results 

During the first three phases of the study, a total of 960 environmental samples were evaluated with both the Neogen Clean-Trace Hygiene Monitoring and Management System and Neogen Petrifilm Plates. In the ATP testing results, the proportion of sites that failed to meet the minimum sanitary requirements day-to-day was highest during Phase 1 but steadily decreased during Phase 2 before leveling off in Phase 3. Microbiological testing results for aerobic count and lactic acid bacteria from complementary surface sampling correlated with the ATP testing results, showing a significant reduction in failures from Phase 1 to Phase 3 (p<0.001). 

Regarding microbiological product quality, in this food manufacturing process, the product underwent two thermal processing steps: an initial heat-treatment of 88°C to reduce microbial load in raw materials, followed by an in-package pasteurization. After implementation of targeted cleaning, quantitative data from packaged, pre-pasteurized food products indicated a significant reduction in the load of microorganisms from Phase 1 to Phase 3. 

Implications for Food and Beverage Manufacturers

The combined use of Neogen Clean-Trace Hygiene Monitoring and Management System and Neogen Petrifilm Plates enabled optimization of cleaning and sanitation. This resulted in improvements that were observed in the manufacturing facility’s environmental hygiene and the microbiological quality of food produced. As the study progressed and the facility became cleaner, fewer failures in testing occurred. These results enabled the team to confidently decrease the number of test sites yet control the cleaning and sanitation process to ensure it delivered the desired results. In addition, the study established an environmental monitoring framework so that in the future, when the facility encounters cleanliness problems or observes unwanted trends in swab failures, they could take appropriate actions to reestablish control of their cleaning and sanitation. The Neogen Clean-Trace Hygiene Monitoring Software also played a critical role in the process through data collection and analysis of performance. Data analysis by the software helped identify and justify opportunities for improvements in cleaning and sanitation. Click the button below to learn more. 

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