Sterilization vs. Disinfection: Levels of Microbial Control

Both processes reduce microorganisms, but differ in extent and application.

Sterilization

Complete elimination of all microbial life: bacteria, viruses, fungi, spores. Required for critical items (surgical instruments).

Methods:

• Heat: Autoclave (121°C, 15+ min) or dry heat
• Chemicals: Ethylene oxide, hydrogen peroxide, peracetic acid
• Radiation: Gamma rays

Disinfection

Reduces pathogens to safe levels on non-critical surfaces. Does not reliably kill all spores (e.g., C. difficile).

Methods:

• Chemicals: Bleach, hydrogen peroxide, quats, alcohols
• Heat: Boiling/steaming >80°C
• UV radiation

Summary

• Sterilization = absolute sterility (critical items)
• Disinfection = safe pathogen reduction (non-critical surfaces)