Recommended pass/fail limits for hand washing: 2,000 RLU

The upper limit is set at twice of the lower limit, and 2,001~4,000 RLU will be “caution”.

*Upper limit will be twice the number of the lower limit.
*Results that are in between upper limit and lower limit should be checked thoroughly. If the results over upper limit, recleaning is required.

Food production site

Janitorial/Cleaning/K-12

The ISSA Clean Standards provides a structured approach for schools and institutional facilities to evaluate the efficiency of their cleaning methods using ATP meters alongside traditional audits. 
The ISSA Clean Standards ｜Test kit ❘ Kikkoman Biochemifa Company

Approach to Inspection Frequency

Incorporate the above approach into food hygiene standards, establish inspection frequencies, and manage and operate accordingly.

1.Set Test Points

Select multiple test points and perform an ATP Test (Kikkoman A3) for swabbing sample or rinse water.
A total of 10 test points, 5 test points from each CIP and COP were selected.

Test point of CIP

Test point of COP

2.Collect data

Collect from before cleaning and after cleaning. Each test point should be tested 5 times to check the range.

Test point 1~5 is CIP after cleaning and test point 6~10 is inside the piping after COP disassembly and cleaning

3.Setting the pass limit

For each inspection point, the second-highest value from the collected data was extracted (indicated in orange). This value is used as the pass limit, ensuring that approximately 80% of the results pass.

If the extracted value is not a whole number, it is rounded up for practical use. The following figure provides examples of pass limit for each inspection point.

4.Confirm the validity of pass limits

To verify whether the set pass limit is appropriate, samples should be collected both before and after thorough cleaning. Once the post-cleaning data is gathered, evaluate the results, if they meet the criteria, the pass limit is considered valid. However, if the pass rate is too high, consider whether further improvements can be made and adjust the pass limit to align with the 80% threshold. Additionally, setting excessively strict limits may discourage employees, so ensure the standards are both effective and motivating.

5.Revalidation

The pass limit must be revalidated whenever there are changes to the cleaning detergent, modifications in the manufacturing process, or a switch to a different supplier. These factors can impact cleanliness levels and overall effectiveness, making it essential to reassess and confirm that the established pass limit remains appropriate and reliable under the new conditions.

Case Study 1: Food and Beverage industry

They switched from a conventional ATP test to Kikkoman A3 to enhance hygiene management in their factories and cafeteria. Their pass/fail limits were set based on initial benchmarks (1,000 RLU for factories, 3,000 RLU for cafeterias) and Kikkoman Biochemifa’ s published research on ATP testing for allergen control. Stricter limits were applied to high-risk surfaces like knives and cutting boards. These thresholds are continuously monitored and adjusted based on operational data.

Case Study 2: Seafood processing plant

Pass and fail limits using a three-tier system: Pass (Blue) for acceptable cleanliness, Fail (Red) for contamination requiring immediate re-cleaning, and Caution (Yellow) for borderline results needing monitoring. Their limits were based on Kikkoman Biochemifa’s reference values, industry research, and benchmarks from other factories. When precise limits were unclear, they initially set a provisional threshold where about 80% of tests passed and refined the values over time. Monthly reviews of test data allowed continuous adjustments to maintain strict hygiene standards. This adaptive approach ensured real-time contamination detection, faster corrective actions, and improved overall hygiene management.

Case Study 3: Hotel

Pass and fail limits using an 80th percentile approach, with 5,000 RLU as the pass limit, 10,000 RLU as the failure limit, and values in requiring monitoring. These limits were established through baseline testing of 50-100 locations, analyzing pre- and post-cleaning ATP results, and setting provisional benchmarks where 80% of test points showed acceptable cleanliness. They continuously review and refine these limits, aiming to lower the pass threshold to 2,000 RLU in line with Kikkoman Biochemifa’s hygiene standards.

Case Study 4: Welfare facility kitchen

ATP testing begins with measuring tap water as a baseline, followed by testing hands, cutting boards, knife handles, the back of refrigerator handles, and mixer blades. The manual provides detailed instructions on swabbing techniques, including applying enough pressure to slightly bend the swab. Pass and fail limits follow Kikkoman Biochemifa’s recommended values without modification.

Note: Apply enough pressure so the swab slightly bends (~10 cm² area).

Note: Apply enough pressure so the swab slightly bends (~10 cm² area).

Case Study 5: Beer factory

The beer factory set stricter ATP cleanliness standards compared to manufacturer recommendations. While the ATP device manufacturer suggests 300 RLU for food equipment, the factory aimed for a much lower threshold, initially targeting 100 RLU and later maintaining 30 RLU for most areas. By setting specific numerical goals, they significantly improved individual hygiene awareness among employees.

Case Study 6: Meat and Poultry

To establish an effective allergen control measure using ATP Testing, conducted a validation study comparing ATP levels and protein content across chicken, pork, and beef. ATP results were shown to correlate closely with protein levels measured by the Bradford method. Found that ATP values under 500 RLU consistently corresponded to less than 1 ppm of residual meat protein—meeting Japan’s allergen labeling exemption threshold. Based on this correlation, a pass/fail limit of <500 RLU was set to help verify cleaning effectiveness and minimize allergen cross-contamination risk in daily hygiene monitoring.

Read full article here

Case Study 7: Soymilk Plant

It is said that tap water typically shows a reading of 0 to 30 RLU. When soymilk is diluted 10,000 times, it exhibits a similar RLU level. Therefore, our factory has established a management threshold of 50 RLU, aiming to achieve this level of cleanliness through washing.
Similarly, we investigated the correlation between the concentration of a soymilk-based beverage (malt coffee flavor) and its RLU values and found comparable results. Based on this data, we have set the ATP Test management threshold to 50 RLU for all types of soymilk beverages produced at the facility.

Case Study 8: Meat Manufacturing Plant

If the pass/fail limit is set at 10,000 RLU, and there are any cases where the ATP test result is below 10,000 RLU but the microbial test exceeds the internal standard (1,000 CFU/100 cm²)—in other words, if any data points appear in the upper-left boxed area of figure—this would indicate that the sample “passes the ATP test but fails the microbial test.” This would mean that 10,000 RLU is not an appropriate pass/fail limit.

However, based on the data in the figure, there were no samples that showed ATP test results below 10,000 RLU while exceeding 1,000 CFU/100 cm² in the microbial test.

On the other hand, if there are samples where the ATP test result exceeds 10,000 RLU but the microbial test result is below 1,000 CFU/100 cm²—i.e., data points in the lower-right boxed area this would indicate that the sample “passes the microbial test but is being subjected to unnecessarily strict cleaning requirements,” implying over-cleaning or excessive cleaning costs.

Looking at the data in figure, only a few samples fell into this area, and thus we determined that the 10,000 RLU pass/fail limit is acceptable.