During sterilization quality control, a biological indicator using Geobacillus stearothermophilus spores is used for which method?
- A Dry heat oven (160°C)
- B Autoclaving (moist heat, 121°C) ✓
- C Ethylene oxide gas sterilization
- D Ultraviolet light irradiation
Correct answer: B. Autoclaving (moist heat, 121°C)
Explanation
Geobacillus stearothermophilus (formerly Bacillus stearothermophilus) spores are the biological indicator of choice for autoclaving (moist heat, 121°C at 15 psi for 15 minutes) because they are resistant to steam sterilization and their destruction confirms adequate sterilization. Bacillus atrophaeus (formerly B. subtilis var. niger) spores are used for dry heat and ethylene oxide. UV light has no standard biological indicator in routine use.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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