Abstract

Importance Considering Increased Recovery of Injured Microorganisms to Attain Reproducible Sterilization Validation

Hideharu Shintani

Final sterilization was conducted to health care products immediately prior to shipping and sterility assurance must be confirmed from the result of biological indicator (BI). The survived microorganisms after sterilization may be mostly injured microorganisms. The auxotrophic characteristics of injured microorganisms are different from those of healthy microorganisms. In that sense, the cultivation conditions of injured microorganisms must be used for confirming reproducible sterilization validation study, otherwise it may result in false negative at shipping test. This is important to attain correct and reproducible sterility assurance. This is indispensable to attain safety assurance of health care products. The evaluation of several sorts of agents must be studied to recover injured microorganisms and support growth reproducibly. It is also important to study for diminishing variation of culture medium performance among culture medium suppliers and that lotto lot variation to attain reproducible sterility assurance. These were studied by adding several sorts of agents to the culture medium inoculating injured microorganisms exposed by moist heating, dry heating, ethylene oxide gas exposure, gamma-ray and electron beam irradiation. Even though sterilizing method may differ, when amino acids mixture, glucose and calcium were added to the culture medium, cultivation performance of injured spores was significantly improved and reproducible sterilization validation can be attained in success.