Coliform Medium is used for the enumeration of Escherichiacoli and other coliforms in food and environmental samples. Bile Salts inhibit Gram-positive bacteria and spore-forming microorganisms while enhancing that of E. coli. Tryptone provides nitrogenous compounds, carbohydrates, vitamins, and minerals. The chromogenic substances X-Glucuronide and Magenta-β-Galactoside detect the activity of β-glucuronidase (E. coli) and β-galactosidase (other coliforms), respectively. Agar is the gelifying agent.