Principles Of Aseptic Technique

Question 1

What does aseptic technique do?

Answer 1

Prevents the contamination of bacterial cultures by other microbes and contamination of the environment.

Question 2

To prevent contamination of pure cultures and apparatus by bacteria in the environment what should be done?

Answer 2

Sterilise all apparatus and media before use

Handle cultures carefully, flaming necks of vessels before opening and closing and using equipment like sterile loops

Question 3

To prevent contamination by bacteria used in the experiment what should be done?

Answer 3

Sterilise work surface before and after w disinfectant
Use the correct handling techniques
Autoclave
Disposable materials like plastic Petri dishes can be sealed inside autoclavable bags, autoclaved and put in bin.

Question 4

What should be done when carrying out inoculation?

Answer 4

• hold bottle in 1 hand and remove lid w little finger
• flame mouth of bottle
• pass inoculating loop through flame until red hot and allow it to cool in air
• lift lid of petrol dish just enough to let in loop
• secure dish w two pieces of tape but not the whole way round as this could create anaerobic conditions for harmful pathogens
• incubate around 25 degrees and don’t open after incubation

Question 5

What is an autoclave?

Answer 5

Glass as metal equipment is heated under pressure at 121 degrees for 15 mins until the required pressure has been reached.