How will you know when the inoculation loop is sterile?
The inoculating loop is sterilised by passing it at an angle through the flame of a gas burner until the entire length of the wire becomes orange from the heat. In this way all contaminants on the wire are incinerated. Never lay the loop down once it is sterilised, or it may again become contaminated.
Why must the loop be flamed after making an inoculation?
Always flame the lip of the culture tube before inserting your sterile loop into the culture. This destroys any contaminating cells that may have been inadvertently deposited near the lip of the tube during previous transfers or by other means.
Why is it important to flame the mouth of the tube before and after every inoculation?
Flaming the Mouth of the Test Tube: Passing the mouth of a tube through the flame of a Bunsen burner creates a convection current which forces air out of the tube. This prevents airborne contaminants from entering the tube.
What does an inoculation loop look like?
An inoculation loop is a thin metal device with a handle at one end and a looped wire at the other end. The looped end is useful for obtaining bacterial samples from colonies growing on media plates or from liquid media, as the loop can hold a drop of liquid, somewhat like a bubble wand holds liquid soap.
How long should you allow the inoculation loop to cool after flaming it?
4. Heat the inoculating loop in the Bunsen burner until it is red hot. Heat several inches of the loop, since that much of it will contact the inside of the petri plate. Allow the loop to cool for a few seconds while you hold it in your hand.
Why should tube caps be held in hand during inoculation?
During transfer, the cap must be held in the same hand as the inoculating loop or needle. Why should test tube caps never be placed on the bench? To prevent contamination and interfering with the bacteria or culture you are working with.
How do you know if a streak plate is successful?
The streaked plate is incubated at 37°C for 24 hours. Examine the colonies grown on the plate carefully. All colonies should have the same general appearance. If there is more than one type of colony, each type should be streaked again on a separate plate to obtain a pure culture.
What is the purpose of flaming the bacterial loop before use and after use?
The purpose of flaming the inoculating loop is to sterilize it to make sure that there is no unwanted bacteria left on the inoculating loop. You should sterilize the inoculating lopp before and after you use it.
Why do you hold the test tube caps in the hand?
Holding the test tube caps in the hand as illustrated in Figure 1. There are bacteria and contamination on our hands, and we don’t want to contaminate the caps or tubes. Excess heat can fixate the samples or kill the organisms.
How do you hold an inoculation loop?
Procedure
- Hold the wire of an inoculation loop in the flame of a Bunsen burner until the wire is bright red.
- Using the flamed loop, pick up a small amount of bacteria—either from bacteria growing on a plate or from bacteria in liquid culture.
- Spread the bacteria on a new agar plate.
- Flame the loop again.
When would you use an inoculation loop?
An inoculation loop, also known as a smear loop, inoculation rod or microstreaker, is a simple tool used primarily by microbiologists to take and transfer a small sample (inoculum) of a microorganism culture, for example for stripping on a culture plate.
How long must the loop be allowed to cool before continuing with inoculations?