A laboratory sterilises empty glassware, paraffin oil and powdered drugs in a hot air oven maintained at 160 degrees Celsius. What is the required holding time after the load reaches the set temperature?
- A 30 minutes
- B 45 minutes
- C 1 hour
- D 2 hours ✓
Correct answer: D. 2 hours
Explanation
The standard hot air oven schedule is 160 degrees Celsius held for 2 hours once the load itself attains that temperature. Shorter schedules apply only at higher temperatures, for example 170 degrees for 1 hour or 180 degrees for 30 minutes, but the classically examined pairing remains 160 degrees for 2 hours. Thirty minutes at 160 degrees is insufficient and will not kill bacterial endospores, which are the reference challenge organism for dry heat.
Reference: Ananthanarayan and Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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