Hot-air oven (dry heat) sterilisation at 160°C for 1 hour is used for which category of materials and is NOT suitable for which of the following?

• A Rubber and plastics — suitable; glass — not suitable
• B Glass syringes and metal instruments — suitable; rubber and plastics — not suitable ✓
• C Surgical dressings — suitable; glass — not suitable
• D Culture media — suitable; glass — not suitable

Explanation

Dry heat (hot-air oven) sterilisation at 160°C for 1 hour (or 170°C for 1 hour, 180°C for 30 minutes) is used for glassware, metal instruments, petroleum jelly, powders, and sharp cutting instruments (as it does not blunt edges like moist heat). It is NOT suitable for rubber, plastics, or textiles (these melt or degrade at these temperatures), culture media, or liquid preparations. Moist heat (autoclave) is preferred for most medical equipment because it achieves sterilisation at a lower temperature (121°C).

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

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Written and medically reviewed by the StethoPrep medical team.