Used in microbiology for the selective isolation and differentiation of coliform bacteria, particularly Escherichia coli, from water, food, and clinical samples. The medium contains indicators that allow E. coli to form blue colonies due to its ability to ferment lactose and produce acid, which reacts with the dye in the agar. This color change makes it easy to identify and count E. coli colonies quickly. Commonly used in environmental monitoring and quality control testing where rapid detection of fecal contamination is required.