[Sterilizing effect and mechanism of electrolyzed water].

OBJECTIVE To study the sterilizing effect and mechanism of electrolyzed-oxidizing water (EOW) and electrolyzed-reductive water (ERW) for Bacillus subtilis var. niger (ATCC9372) and Escherichia coli (8099). METHODS The generations of EOW and ERW were made in the ion membrane electrolysis cell. The sterilization manner was the suspension quantitative germicidal test. RESULTS The killing rate of EOW for Bacillus subtilis var. niger was 99.59% in 30 minutes and the killing logarithm value was 2.38 log cfu/ml; the killing rate of ERW for Bacillus subtilis var. niger was 94.62% in 60 minutes and the killing logarithm value was 1.27 log cfu/ml; the killing rate of ERW for Escherichia coli was 100% in 30 minutes and the killing logarithm value was 8.26 log cfu/ml. When the available chlorine content (ACC) value in EOW was 74.90 mg/L and killing time was 30 minutes, the killing rate for Bacillus subtilis var. niger was 99.89% and the killing logarithm value was 2.67 log cfu/ml. When the ACC value was 6.82 mg/L, the killing rate for Bacillus subtilis var. niger was 83.30% and the killing logarithm value was 0. 78 log cfu/ml under the same time. When the oxidizing-reductive potential (ORP) and pH values of EOW were 1138 mV and 2.24 respectively, the killing rate for Bacillus subtilis var. niger was 99.99%. When the ORP and pH values of EOW were 883 mV and 5. 43 respectively, the killing rate of Bacillus subtilis var. niger was 99.73%. When the ORP value of ERW is -918 mV, the sterilizing rate for Bacillus subtilis var. niger was 94.62%; when the ORP value is -155 mV, the sterilizing ratio was only 40.19%. CONCLUSION It indicates that the sterilizing mechanism of EOW is mainly chemical processes (ACC), while the physical factors are auxiliary. The sterilizing mechanism of ERW is physics sterilizing that the mainly factor is ORP.