Methods of Sterilization

Physical Methods
- Heat Sterilization
  - Moist Heat: Involves autoclaving (121°C for 15-20 mins) which kills microorganisms through protein denaturation.
  - Dry Heat: Uses hot air ovens (160-180°C for 1-2 hours) for sterilizing materials that may be damaged by moisture.
- Radiation Sterilization
  - Ionizing Radiation: Uses gamma rays or electron beams to damage microbial DNA.
  - Non-Ionizing Radiation: UV light is effective for surface sterilization but has limited penetration.
- Filtration
  - Uses membranes to remove microorganisms from liquids and air. Effective for heat-sensitive solutions like antibiotics.
Chemical Methods
- Ethylene Oxide (EtO): Gas used for sterilizing heat-sensitive items; effective at low temperatures. Requires aeration post-treatment to remove residual gas.
- Hydrogen Peroxide: Vaporized hydrogen peroxide is effective for thermolabile instruments and surfaces.
- Peracetic Acid: Effective for sterilizing surgical instruments and medical devices; often used in liquid form.
Plasma Sterilization
- Utilizes hydrogen peroxide vapor that is converted to plasma. Effective at low temperatures and suitable for heat-sensitive items.

Definition: Sterilization processes that occur at temperatures lower than 60°C, suitable for heat-sensitive materials.
Methods
1. Ethylene Oxide (EtO) Sterilization
  - Suitable for heat-sensitive instruments.
  - Provides thorough penetration and is effective against spores.
  - Requires careful handling and adequate aeration to eliminate toxicity.
2. Hydrogen Peroxide Sterilization
  - Gaseous or vaporized form is utilized.
  - Acts quickly and is compatible with many materials.
  - Breaks down into water and oxygen, leaving no toxic residues.
3. Plasma Sterilization
  - Involves using hydrogen peroxide vapor and transforming it into plasma with low temperature.
  - Rapid cycle times and no toxic residuals.
Applications
- Common in healthcare settings for sterilizing surgical instruments, endoscopes, and other heat-sensitive items.
Limitations
- Requires specific conditions (humidity, temperature) for effectiveness.
- Not suitable for all materials (e.g., certain plastics may be degraded).

Heat Sterilization
- Moist Heat: Autoclaving at 121°C for 15-20 minutes effectively denatures proteins, killing microorganisms.
- Dry Heat: Utilizes hot air ovens at 160-180°C for 1-2 hours, suitable for moisture-sensitive materials.
Radiation Sterilization
- Ionizing Radiation: Employs gamma rays or electron beams to damage microbial DNA, effectively sterilizing materials.
- Non-Ionizing Radiation: UV light sterilizes surfaces, though penetration is limited.
Filtration:
- Employs membrane filters to remove microorganisms from liquids and air, especially useful for heat-sensitive solutions like antibiotics.

Ethylene Oxide (EtO):
- A gas used for sterilizing heat-sensitive items; requires low-temperature application and aeration to remove residuals post-treatment.
Hydrogen Peroxide:
- Vaporized form sterilizes thermolabile instruments and surfaces without leaving toxic residues.
Peracetic Acid:
- Liquid form effectively sterilizes surgical instruments and medical devices.

Utilizes vaporized hydrogen peroxide converted into plasma, enabling sterilization at low temperatures, ideal for heat-sensitive materials.

Definition: Processes that sterilize at temperatures below 60°C, suitable for heat-sensitive materials.
Methods
- Ethylene Oxide (EtO) Sterilization:
  - Ensures thorough penetration effective against spores; requires careful handling and adequate aeration for safety.
- Hydrogen Peroxide Sterilization:
  - Fast-acting and compatible with various materials, decomposes into water and oxygen, leaving no toxic residues.
- Plasma Sterilization:
  - Converts hydrogen peroxide vapor to plasma with rapid cycle times and no toxic residuals.
Applications:
- Widely used in healthcare to sterilize surgical instruments, endoscopes, and other delicate heat-sensitive items.
Limitations:
- Requires specific conditions (humidity and temperature) for optimal effectiveness; not all materials are suitable, as some plastics may be degraded.