For the purpose of improving hygienic quality of health-foods, sterilization effects of y ray and ozone on microoganisms associated with food cultured in the media and contaminated in Angelica keiskei powder were investigated. Ozone was immersed in water and sprayed in air, on the concentration of 3 mg liter^(-1) at an air flow rate of 5 liter min'. Test strains cultured in the media completely inhibited by γ-ray at irradiation doses of 0.25--2 kGy. In the case of ozone, test bacteria inactivated after treatment of 10-20 minutes, but test mold, Aspergillus llavus was not effective. Strains contaminated in Angelica keiskei powder completely inhibited by γ-ray at irradiation doses of 2.5-7.5 kGy. However, when the powder was sprayed with ozonized air for 10 hours, Bacillus subtilis and Staphylococcus aureus among five strains were eliminated.