Abstract
Experiments were conducted to evaluate effect of several factors affected for efficacy of disinfectant solutions on reduction of viable bacteria. It was considered that important factors would be chemical component of disinfectant, concentration and amount of the solution sprayed, elapsed time after spraying, temperatures of circumstance and the solution on spraying and repeat spraying of the solution.
A plywood test pieces (1×5cm) contaminated 105.4-105.7 of bacteria were hanged in the wooden box of 1m3 of capacity. Three kinds of disinfectant solution were sprayed like a mist and reduction of viable bacteria contaminating the pieces were counted. Orthodichlorobenzene, invert soap and iodophor were used in this experiment.
One tenth of bacteria contaminated pieces before spraying were reduced by spraying each disinfectant solution. No differences were observed in reduction of bacteria by spraying the solution among three kinds of disinfectant. When high concentrations and large amounts of each disinfectant solution were sprayed, respectively, approximately 1/10 of bacteria contaminated the pieces before spraying were reduced. No differences were observed in bacterial counts after spraying between concentrations of the solutions. No differences also observed between amounts of the solutions sprayed. While main reduction of bacteria was recorded within 24 hours, a few bacteria were reduced from 24 to 72 hours after spraying. When temperature of circumstance and the solution were kept at 5 and 30°C, respectively, no difference also were observed in bacterial reduction between temperatures. Marked reduction of bacteria was not observed when spraying same or different kinds of the solution repeatedly 3 times at intervals of 24 hours. One tenth of bacteria contaminating the pieces before spraying were reduced by 1st spraying. A fewer bacteria less than 10-1 were reduced by 2nd and 3rd spraying, respectively.
