Control of Microbial Growth (Autoclave | M) Flashcards
What is an autoclave and its principle?
It is a sealed device (similar to pressure cooker) that kills (all) microorganisms using saturated steam under pressure
What are killed by autoclave?
The use of moist heat facilitates killing of all microorganisms, including heat-resistant endospores w/c is achieved by heating the mats inside the device at temperatures above the boiling point of H2O
What is the principle of gas laws (in autoclaving)?
Killing all microorganisms can be achieved by raising the pressure inside the device
What are the principles of autoclave?
1) Steam penetrates objects in the autoclave
2) Condensation creates (-) pressure and draws in additional steam
3) Moist heat kills microorganisms via coagulation of proteins
How are microorganisms killed (via autoclaving)?
Via the coagulation of proteins (of microorganisms)
What are the types of autoclave?
1) Pressure Cooker Type
2) Common Laboratory Autoclave
3) Vertical Autoclave
4) Horizontal Autoclave
5) Large Automatic Hospital Autoclave
What are the different methods that can be used for sterilization controls (of autoclaving)?
1) Use of biological indicator
2) Use of autoclave tapes
3) Use of Browne’s tube or thermocouple
What microorganism (and its component) is used as a biological indicator for sterilization controls (of autoclaving)?
Spore of Geobacillus stearothermophilus
What are the characteristics of autoclave tape?
1) Adhesive-backed paper tape
2) Heat-sensitive
What is a Browne’s tube?
It is a temperature measuring device
What is the purpose of Browne’s tube (for sterilization controls in autoclaving)?
It records the temp by a potentiometer
What device records the temp (via the use of Browne’s tube)?
Potentiometer
What is the interpretation for the following circumstances?
a. Presence of yellow medium (after autoclaving)
b. Presence of red medium (after autoclaving)
a. Presence of yellow medium (after autoclaving): means spores are viable; autoclaved objects are not sterile
b. Presence of red medium (after autoclaving): means spores are killed; autoclaved objects are sterile
What are the uses (or where can autoclave be used) of autoclave?
1) Surgical instruments
2) Culture media
3) Autoclavable plastic containers
4) Plastic tubes and pipette tips
5) Solutions and water
6) Biohazards (or biohazardous) waste
7) Glasswares (autoclave resistible)
