Abstract
The heated dolomite powder slurry was investigated for the sporicidal activity against Bacillus subtilis spore. B. subtilis spore used in this study did not decreased at pH 1 or 13 for 2 h, indicating that the spores had a sufficient resistance. However, the dolomite powder heated at 1000℃ for 1 h could kill B. subtilis spore, even the pH of the slurry was 12.7. The dolomite powder heated at 700-750℃ did not exhibit the sporicidal activity. The sporicidal activity appeared when the dolomite powder heated at 800℃ or higher, and the raise in the heating temperature increased with the sporicidal activity. This temperature corresponded to that of generation of CaO. On the other hand, MgO did not contribute to the sporicidal activity of the heated dolomite powder. To elucidate the sporicidal mechanism of the heated dolomite powder against Bacillus subtilis spore, the generation of active oxygen from the slurry was examined by a chemiluminescence analysis. The luminescence intensity has increased when the slurry concentration rose. The results suggested that active oxygen species generated from the heated dolomite powder were associated with the sporicidal activity.
