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Vol.37 No.5 contents | Japanese/English |
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Full Text of PDF (1,174K) Article in Japanese |
A Quantitative Fluorescent Marker Method for Evaluation of Surface Cleanliness Using Digital Image Data
Hajime KUROZU1)2), Erisa SUGAWARA2), Yasuhiro SAEKI2), Takumi KAJIURA2) and Satoshi KIMURA2)
1)Rejoice-company CO., Ltd., 2)Division of Infection Prevention and Control, Division of Postgraduate School of Healthcare Tokyo Healthcare University
The fluorescent marker method is a simple and inexpensive way to evaluate the cleanliness of healthcare environments in real time. However, quantitative relationships between fluorescent signal and microbial removal have not been established.
Here, a quantitative method was developed using pixel values from digital photographic images of fluorescent markers, and the relationship between the rate of removal of fluorescent markers and the rate of removal of microorganisms from three surfaces: stainless steel and black and white vinyl chloride was determined.
Specific amounts of solutions of commercially available fluorescent markers were applied adjacent to the samples of S. aureus, and the surfaces were photographed before and after wiping with a hydrophobic wipe. The fluorescent marker was quantified based on an assumed exponential relationship between the fluorescent marker and measured pixel values with respect to the maximum pixel value (255); coefficients of correlation between the calculated and actual amounts of fluorescent marker were in excess of 0.99 for each surface. The coefficients of determination for the removal rates of S. aureus and fluorescent marker on the white and stainless steel surfaces were 0.46 and 0.61, respectively. Notably, the agreements were good only when the fluorescent marker removal rate was 90% or higher. These results confirm the possibility in quantifying the amount of fluorescent marker on a surface using digital image data, and this measurement can be used to estimate surface cleanliness.
Key words：cleaning evaluation, fluorescent marker method, quantitative evaluation, image data, pixel value
e-mail: h-kurozu＠rejoice-company.co.jp
Received: April 13, 2022
Accepted: May 31, 2022
37 (5)：174─182,2022
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