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Updated: Aug 7, 2026

Failure of Cleaning Verification in Pharmaceutical Industry Due to Uncleanliness of Stainless Steel Surface
Published on: August 11, 2017
Comparative analysis of four hospital cleaning validation methods
William A Rutala1, Hajime Kanamori2, Maria F Gergen3
1Division of Infectious Diseases, UNC School of Medicine, Chapel Hill, NC.
Background:
To assess 4 methods for determining the cleanliness of hospital surfaces.
Methods:
We conducted a prospective study in 10 intensive care units and 14 non-intensive care units patients at an academic hospital. The environmental surfaces were sampled just before and after daily cleaning and disinfection.
Results:
There was no statistical correlation between adenosine triphosphate (ATP) levels and standard aerobic plate counts. Compared with cleanliness based on standard aerobic cultures (<62.5 CFU/Rodac), 72% (90/125) were classified as clean using fluorescent markers, while 13.5% (17/126) and 27% (34/126) were classified as clean using ATP<250 relative light units and ATP<500 relative light units, respectively.
Conclusions:
The fluorescent marker was the most useful tool in determining the cleanliness of hospital surfaces by demonstrating how thoroughly a surface was wiped as it mimicked the microbiological data better than ATP.
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