Which of these methods can be used to determine the number of viable microorganisms in a sample?

Question

Quizplus · Accepted Answer

Measuring colony forming units per ml is the most reliable method to determine the number of viable microorganisms in a sample as it counts only the live, viable cells that are able to form colonies on a solid culture medium. This method involves plating serial dilutions of the sample on a suitable medium and counting the number of colonies that grow after incubation. The other methods mentioned (light scattering in a spectrophotometer, measuring total cell mass, and counting a known volume of cells in a hemocytometer) do not differentiate between live and dead cells and may overestimate the number of viable microorganisms.

Which of These Methods Can Be Used to Determine the Number