Influence of free residual chlorine concentration and pH on the efficacy of hand-washing with electrolyzed water
2001
Takeshita, A. (Toto Co. Ltd., Chigasaki, Kanagawa (Japan)) | Ando, S. | Takahashi, Y.
The influence of factors, namely the free residual chlorine concentration and pH of Electrolyzed Water (EW), on hand-washing efficacy was investigated, and this efficacy was compared with that of hand-washing with medicated liquid soap and running water. Nine types of EWs were prepared and each of them had a pH of either 2.9,6.0 or 7.7, and a free residual chlorine concentration of either 4.4ppm, 19.8ppm, or 38.8ppm. The efficacy of washing hands contaminated by about 10**5 CFU Staphylococcus aureus, which was used as the index bacilli, was examined. Consequently, when the concentration of free residual chlorine was 19.8ppm and 38.8ppm, lower pH gave a higher hand-washing efficacy. On the other hand, when the concentration of free residual chlorine was 4.4 ppm, the hand-washing efficacy was not affected by the value of pH and was lower than that when the free residual chlorine concentration was 19.8ppm or 38.8ppm. With certain conditions of EWs, the method of hand-washing with EW was more effective than the method with the medicated liquid soap and running water. Moreover, the influence of hand-washing time on the hand-washing efficacy was investigated and no significant difference was statistically seen between 10 seconds and 30 seconds.
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