Radiation Sterilization of Medical Devices and Supplies. V. : Effects of γ-Radiation on the Plastic Petri Dish

An applicability of 60Co γ-ray irradiation for sterilization of polystyrene petri dishes was investigated. It was found that the petri dishes which were heavily contaminated by the spores of B. subtilis and B. pumilus could be perfectly sterilized with γ-ray irradiation at 2.5 M rad. Neither significant coloring and crazing of the irradiated dishes nor detrimental effect on their use in bacterial experiment was observed. From the observation of washing tests, it is supposed that the silicone on the surface of plastics is grafted with the plastics by means of the irradiation at 2.5 M rad.