(Laboratory) Autoclaving and other Sterilization Techniques Flashcards
Principle of Autoclaving:
Moist heat under steam pressure
Preferred time and temperature when autoclaving media, liquids, utensils, glass pipettes:
121 degree Celsius, 15 pounds per square inch (psi) for 15 minutes
Preferred time and temperature when autoclaving decontaminating medical wastes:
132 degree Celsius, 15 pounds per square inch (psi) for 30-60 minutes
Identify the Part of an Autoclave:
The main component of a steam autoclave; it is where the materials to be sterilized are placed.
Pressure Chamber
Identify the Part of an Autoclave:
Seal the chamber and maintain the sterilizing conditions within the autoclave.
Lid
Identify the Part of an Autoclave:
Indicates the pressure inside the autoclave.
Pressure Gauge
Identify the Part of an Autoclave:
Pressure within the autoclave can be controlled by lifting the whistle and releasing certain amount of vapor.
Pressure Releasing Unit/Whistle
Identify the Part of an Autoclave:
Present underneath the chamber to heat the water and generate steam.
Steam Generator
Sterilize the materials inside the chamber using _____ and _____
Moist Heat
Pressure
The _____ ensures the rapid penetration of heat into deeper parts of the material.
High Pressure
The _____ causes denaturation of microbial proteins.
Moisture
Once sterilization is completed, _____ inside the chamber is released through the whistle.
Pressure
Once sterilization is completed, pressure inside the chamber is released through the _____.
Whistle
Steps in running an Autoclave:
- Check the inside of the autoclave if there are items left from the previous cycle
- Place sufficient amount of water inside the chamber
- The materials to be sterilized are then placed inside
- The lid is closed using screws to ensure airtight condition, and the electric heater is switched on
- The water then boils and the pressure is allowed to reach the designated level
- Once the pressure is reached, the whistly blows to remove excess pressure from the chamber
- After the whistle, the autoclave is run for a holding period (15 minutes or more)
- The heater is switched off and the autoclave is allowed to cool until the pressure gauge indicates the pressure inside has lowered down
- The lid is opened and the sterilized materials are taken out of the chamber
Uses of an Autoclave:
- Used in order to sterilize materials in the laboratory such as culture media, glassware and other instruments
- Used in order to sterilize medical wastes that may contain dangerous microbes
Precautions in using the Autoclave:
- The autoclave should not be overcrowded in order to ensure that all parts of the material can be penetrated by the steam
- Wastes and clean items should be autoclaved separately
- Do not attempt to open the lid when the autoclave is running
- Avoid placing materials that might melt inside the autoclave (plastic trays, etc.)
Types of Dry Heat Sterilization:
- Direct Flaming
- Oven Heating
