Exercise 12.1 - Aseptic Cell Transfers

Level I

Figure 12.3 Flaming a wire loop and removing cap

Materials

• Bunsen burner
  
• Wire loop
  
• Petri plate or broth tube
  
• Bacterial culture
  
• Microscope slides

Procedure

1. Pick up the inoculating loop and hold it pointed down into an open flame until the loop glows red. This process sterilizes the loop of wire and is known as "flaming" the loop. It will result in a sterile loop and will not contaminate your stock culture. If there are liquids already on the loop, the loop should be gradually placed into the flame to dry the loop. If the loop is rushed into the flame, the drop of liquid will splatter and spread bacteria over your work surface.

2. Pick up a broth culture in one hand, while holding the loop in the other. With the last two fingers of the hand holding the loop remove the cap from the culture and gently flame the top of the test tube (do not overheat). Insert the flamed inoculating loop into the test tube until it is submersed in the broth. The loop should be allowed to cool slightly before immersion. Retract a small quantity of the broth held in the loop and replace the cap on the culture.

3. Open the top of your transfer vessel (tube with water or nutrient agar) and flame the open top of the tube. Insert the loop into the tube and into the liquid in the tube. Withdraw the inoculating loop slightly from the liquid, blot gently on the inside of the tube and completely remove from the tube. Replace the top on the tranfer tube.

4. Immediately flame the inoculating loop.

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