Question

During streak plate technique: Why is it necessary to flame the loop in between streaks?A. To grab bacteria from previous streaked area going into new streaked areaB. In order to count colonies from streaked areas based on previous areasC. To reduce number of bacteria from previous streaked area going into new streaked areaD. to kill bacteria and avoid contamination

Answer 1

Answer: Option C

Explanation:

In case of streaking, the loop is flame in between streaks. This is done in order to prevent the number of bacteria from entry into the new area of the streak.

The bacterial population is taken from the loop and is streaked on the petri dish containing the nutrient medium.

This loop is flamed and then again used for streaking the another bacterial species. So, no two bacterial species should be mixed with each other do it is flamed in between the intervals of streaking.

Answer 2

Answer:

Option C, To reduce number of bacteria from previous streaked area going into new streaked area

Explanation:

A loop is sterilized by flaming the loop in between streaks. A streak plate method is used to isolate discrete bacterial colonies so that the number of organisms in the inoculums is reduced. During the procedure, microorganism get deposited in the initial region. This would cause growth of culture across the streaked area and hence the loop is sterilized.

In order to sterilize the loop, it is kept between the blue flame of the Bunsen burner after every section so that the number of depositing microorganism reduces.

Hence, option C is correct