We examined the pasteurization effect of superheated steam containing micro-droplets of hot water (Aqua-gas, 115 deg C), superheated steam (120 deg C, 180 deg C) and hot water (100 deg C) to control Bacillus subtilis spores on the potato surface. Decimal reduction times of B, subtilis spores with the heating media were 2.8, 5.0, 6.3 and 6.8 minutes respectively. In case of the Aqua-gas, almost 90% of the spores were presumably washed away from the potato surface by condensed steam and the micro-droplets within 2.5 minute. After the condensation of the steam on the potato stopped, the potato surface was subsequently pasteurized effectively by the Aqua-gas since the surface was kept wet by the micro-droplets and it was heated with high temperature steam. To examine the pasteurization effect of actually cooking with these heating media, kakuni (boiled pork belly with soy sauce) and gyusuji (boiled beef tendon with soy sauce) were cooked using the Aqua-gas (115 deg C) , superheated steam (180 deg C) and a gas stove. The bacterial numbers of the food cooked with the superheated steam and the gas stove increased to more than 103CFU/g after 5 days of storage at 10 deg C. In contrast, the bacterial numbers of the samples cooked with the Aqua-gas were maintained at less than 300 CFU/g during storage.