Views: 30
Moist Heat Sterilization
Moist heat method of sterilization
Moist heat sterilization involves methods such as
- Pasteurization
- Tyndilization
- Autoclaving
Method |
Principle/Conditions |
Advantages |
Disadva |
Uses |
Pasteurization |
• Heating to below boiling point (generally 77oC) for up to 30 minutes |
• Can be used on heat sensitive liquids and medical devices • Low cost |
• Not reliably sporicidal |
• Milk and dairy products • some heat-sensitive medical equipment |
Tyndallization (Fractional Sterilization) |
• Heating to 80-100oC for 30 mins on successive days, with incubation periods in between |
• Resistant spores germinate and are killed on the second and third days |
• Time consuming • not reliably sporicidal |
• Heat sensitive materials such as bacteriologic media, solutions of chemicals, biological materials |
Autoclaving |
• Apply Steam under pressure usually at 121oC/15 psi for 15-90 mins (gravity displacement autoclave) or at 132oC/27 psi for 4-20 minutes (pre-vacuum autoclave) |
• Minimal time required • Most dependable sterilant for lab use |
• Loading and packing critical to performance • Shielding dirt must first be removed • Maintenance and quality control essential • Damages heat-sensitive items |
• Penetration of sterile glassware, media and instruments • Decontamination of reusable supplies and equipment • Decontamination of infectious waste |