ABSTRACT
OBJECTIVE: To establish an oil bath method to determine the D values and Z value of biological indicators in spore suspension forms for moist heat sterilization. METHODS: Spore suspension was sealed up in glass capillary, which was heated by thermostat oil bath. D value and Z value were determined by survivor curve method. RESULTS: The D values of Geobacillus stearothermophilus ATCC7953 spores suspension at 117, 121 and 125 ℃ were 7.04, 2.18 and 0.65 min, respectively, and the Z value was 7.75 ℃. The D values of Clostridium sporogenes CMCC(B)64941 spores suspension at 95, 100 and 105 ℃ were 11.36, 2.85 and 0.45 min, respectively, and the Z value was 7.14 ℃. CONCLUSION: By simulating the sterilization of aqueous liquid with oil bath method, the D values and Z values of biological indicators in spore suspension forms for moist heat sterilization can be determined conveniently and accurately(r2 is above 0.980 0). The oil bath method can be used for heat resistance research of biological indicators in spore suspension form for moist heat sterilization.