DC (Differential Coliform) Medium is a selective medium for the growth and isolation of Escherichia coli. Bile Salts inhibit Gram-positive bacteria and spore-forming microorganisms while enhancing that of E. coli. Proteose Peptone, Tryptose, and Yeast Extract provide nitrogenous compounds, carbohydrates, vitamins, and minerals. Lactose is the fermentable carbohydrate. Neutral Red is the pH indicator that shifts to red upon medium acidification due to Lactose fermentation. Sodium Chloride maintains the osmotic balance and Agar is the gelifying agent.