Question

The goal of streaking for isolation is to spread an inoculum of bacteria thinner and thinner with each pass for the identification of individual colony-forming units. What action must be performed between each step to ensure this?

An additional inoculum of bacteria must be added.
Sterilization of the agar plate must be performed.
The agar plate must be incubated overnight.
Sterilization of the loop must be performed.

Answer 1

Between each step in the streaking for isolation technique, the inoculating loop must be sterilized by flaming to prevent cross-contamination and aid in separating individual colony-forming units for the identification of pure cultures.

Step-by-step explanation:

The action that must be performed between each step during the streaking for isolation technique is sterilization of the loop. This step is crucial to ensure that bacteria are not transferred from one sector of the agar plate to another, which could hinder the separation of individual colonies. Between steps, you would flame the inoculating loop to sterilize it, and then allow it to cool briefly in the agar before continuing with the streaking process. This action helps spread the inoculum thinner with each pass and results in individual colony-forming units that can be identified and used to create a pure culture.