Definition
Decontamination
- removal of gross organic debris
Disinfection
- process of eliminating all microorganisms except bacterial spores
Sterilization
- process to eliminate or destroy all forms of microbial life, including bacterial spores
Techniques of Sterilisation
1. Wet heat
2. Dry heat
3. Chemical
4. Irradiation
1. Wet Heat / Pressurized Steam
Autoclaving
- most reliable
- metal instruments
- glass
- some plastics, fabrics & rubbers
Technique
- 121° >103 kPa ~ 15 minutes
Flash
- 134° 205kPa 3 minutes
2. Dry Heat
Uses
- glassware
- oils & fats
Technique
- fan-driven oven
- 160° C
- minimum 2 hours
3. Chemical
indications
- instruments damaged by heat
A. Ethylene Oxide
Uses
- items unable to withstand heat of >60° C
- instruments with electrical, fibre-optic or electronic components
- heat sensitive plastics
Technique
- ethylene oxide must reach all surfaces of article to be effective
- At 60°C in 60% humidity
- minimum time 12 hours
B. Glutaraldehyde
Most common used
- thoroughly cleaned instrument immersed in solution
- sterilisation with immersion for 10 hours
- disinfection with immersion for 20 minutes
- precautions with use & thorough rinsing because very irritant
4. Radiation / Sterrad
Hydrogen Peroxide made to release free radical by radiowave - 45° C
Summary
| Temperature | Pressure | Time | ||||
| Wet Heat | Complete | 121o | 103kpa | 15 min | ||
| Flash | 134o | 205kpa | 3 min | |||
| Dry Heat | 160o | 120 min | ||||
| Chemical | Ethylene Oxide | 60o | 12 hours | |||
| Gluteraldehyde | 10 hours |