Which sterilization method is appropriate for sharpened instruments such as scissors and for oily preparations like liquid paraffin?

• A Autoclaving at 121°C for 15 minutes
• B Boiling at 100°C for 30 minutes
• C Membrane filtration through 0.22 µm filter
• D Hot air oven at 160°C for 2 hours ✓

Explanation

The hot air oven at 160°C held for 2 hours is the standard dry heat cycle for glassware, metal instruments including sharps, oils, greases, and powders, all of which are either damaged by moisture or impermeable to steam. Oils cannot be penetrated by moist heat, so autoclaving is ineffective for them, and boiling does not kill spores reliably.

Reference: Ananthanarayan and Paniker's Textbook of Microbiology, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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