How is total viable count conducted in a laboratory?

In the lab, a sample (water, swab, air plate, etc.) is applied to a nutrient-rich agar plate. The plate is then incubated at a set temperature (typically 30–37°C) for 24 to 72 hours, allowing viable microorganisms to form visible colonies. Analysts count these colonies and express the result as CFU (colony forming units) per mL, gram, or cm², depending on the sample type.