These threshold settings have been determined based on plate counts on different instruments, surfaces and daily uses. Hygiena recommends that you determine your own threshold settings by doing plate counts in conjunction with ATP swabbing or by using one of the two "Recommended Practices" provided below.
When using the threshold setting provided by Hygiena for the SystemSURE II, readings less than 10 RLUs indicates that the surface is considered clean. Readings between 11 - 29 RLUs indicates a warning that the surface is not adequately clean. If the reading is greater than 30 RLUs, the surface is considered dirty.
If you are not following these guidelines and have established your own company guidelines then we recommend you follow the following two practices:
Recommended Practice
Identify control points and critical control points.
Clean product surfaces.
Conduct ATP Hygiene Monitoring tests at several locations and over several days to give 20-50 results. Calculate the average and standard deviation (s.d) for the RLU values.
Set limits as:
Pass <= Mean RLU
Caution >= Mean RLU < Mean + 3 (s.d)
Fail >= Mean RLU + 3 (s.d)
Pass 0 - 10 RLU
Caution 11 - 29 RLU
Fail > 30 RLU
Monitor results and assess trends. Recalculation regularly to optimise limits and improve standards.
Alternative Procedure
Identify control points and critical control points.
Clean product surfaces thoroughly, even 2 or more times to achieve the best possible level of cleanliness.
Conduct ATP Hygiene Monitoring tests at each location, using 5-10 test replicates.
Calculate the average RLU which is considered to be the pass level.
Fail limits are determined by multiplying the Pass level by 2 or 3 fold.
