CFU counting methods

CFU (Colony Forming Units) counting measures the number of viable bacteria or fungi in a sample. To do this, a small amount of the sample is diluted and spread onto a nutrient agar plate. After incubation, each live microorganism grows into a visible colony. Countable plates (usually with 30-300 colonies) are selected, and the number of colonies is multiplied by the dilution factor to determine the original sample's microorganism concentration. This method helps assess cleanliness, safety, and microbial loads in health, food, and environmental testing.