A colony-forming unit (CFU) is a term used in microbiology to describe a unit that can form a colony of microorganisms, such as bacteria or fungi, when cultured in a suitable environment. Each CFU represents a viable organism or a group of organisms that can grow and multiply, leading to the formation of visible colonies on a growth medium. CFUs are important for quantifying the number of viable microorganisms in a sample. Researchers often use CFUs to assess the effectiveness of antimicrobial treatments or to evaluate the microbial load in various environments, such as food safety or clinical settings.