Coliform Chromogenic Medium is a specialized culture medium designed for the rapid detection and quantification of Escherichia coli in food, drinking water, and clinical samples. It achieves precise identification through an enzymatic chromogenic mechanism: Escherichia coli expresses β-glucuronidase, which hydrolyzes MUG to release 4-methylumbelliferone. This produces characteristic blue-white fluorescence under 366 nm UV light, while colonies appear blue to purple with smooth, moist surfaces, some exhibiting a metallic sheen; Non-target bacteria (e.g., Salmonella, Shigella) lack this enzymatic activity, appearing colorless or pale pink, enabling efficient differentiation.