What technique uses a loop to streak a mixed sample over the surface of a solid culture medium?

The Streak Plate Technique is a fundamental method in microbiology used to isolate a specific microorganism from a mixed sample. This technique involves the use of an inoculating loop, which is sterilized and then used to draw a line across the surface of a solid culture medium. The loop is re-sterilized between streaks, which helps to dilute the sample over a larger area as the loop is streaked in a pattern, typically in quadrants.

The primary goal of this technique is to produce isolated colonies of a species by exploiting the fact that as the loop is streaked across the agar surface, fewer and fewer cells are deposited, eventually leading to individual colonies that arise from single cells. Each colony can be pure and free from contamination, which is essential for subsequent identification and study of microorganisms.

In contrast, the other methods mentioned serve different purposes. The Pour Plate Technique involves mixing a liquid sample with molten agar and pouring it into a plate, where microorganisms are trapped within the medium as it solidifies. The Spread Plate Technique involves spreading a diluted microbial sample evenly across the surface of the agar using a sterile spreader, rather than streaking it. The Filtration Technique is utilized for separating microbes from liquids by passing the liquid through a filter