Final answer:
In the viable plate count method, each colony represents one cell from the sample. This technique is crucial for estimating the number of live bacteria in a sample and obtaining pure cultures. Despite possible underestimation, the method remains valuable for assessing bacterial populations.
Step-by-step explanation:
In the viable plate count method, each colony represents one cell from the sample. The technique involves spreading a diluted sample of bacteria onto solid agar media and waiting for the bacteria to grow into visible colonies. Each of these colonies originates from a single bacterial cell that has reproduced to form a cluster of identical cells. This method is crucial in microbiology for estimating the number of viable bacteria in a sample, expressed as colony-forming units per milliliter (CFU/mL). Samples are diluted serially to ensure that the resulting colonies are not too few (<30) or too many (>300), which helps in getting a reliable count that is closer to the actual cell count.
The viable plate count is a widely used procedure for isolating and counting live bacterial cells. Serial dilutions and plating techniques like the pour plate method or spread plate method facilitate counting of the viable bacteria. Although the viable plate count underestimates the actual number of live cells due to reasons such as aggregate-forming bacteria or viable but nonculturable cells, it remains a valuable method for obtaining pure cultures and for assessing bacterial populations in various contexts.