Radiation Sensitivity of Microorganisms Adhering to the Crude Drug "Bezoar Bovis" and Stability of its Main Components for γ-Ray Irradiation

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The sterilization dose (SD) of γ rays required for the microbial-contaminated crude drug "Bezoar Bovis" and the residual rates of its characteristic and effective components, bilirubin and some kinds of cholic acid, were studied experimentally. Samples of Bezoar Bovis made in America were used. The contamination level of the samples was 2.2×10^8 cells of bacteria and 6.0×10^5 spores of fungi per g specimen. The survival rate of these microorganisms showed nearly an exponential dependence on radiation dose. The decimal reduction doses (D_<10>) for the bacteria and fungi were found to be 1.5kGy and 1.1kGy respectively. From these values, the dose required for attaining the contamination level provided by the administrative guidance (Bacteria, <1.0×10^3 cells/g; Fungi, <1.0×10^2 spores/g) were estimated to be 7.5kGy and 4.3kGy, respectively. The G-values for bilirubin, cholic acid and deoxycholic acid were calculated to be 13, 6 and 8, respectively. If the sterilization treatment is carried out with a dose less than 10kGy on the specimen in a dry powder state, the reduction of the main components such as bilirubin and cholic acids by γ-ray irradiation is considered to be negligible.
1994-03-31