For enumeration of coliform bacteria in water and foods. BRILLIANT GREEN BILE AGAR(VEG.) is used for enumeration of coliform bacteria in water and foods. It uses Basic fuchsin to differentiate between positive lactose-fermenting and lactose-non-fermenting bacteria. The Veg. Peptone provides the essential nutrients for growth: nitrogen, vitamins,minerals and amino acids. Lactose is the fermentable carbohydrate providing carbon and energy. Sodium deoxycholate and Brilliant green inhibit Gram-positive bacteria and most Gram-negative bacteria exceptColiforms. Acetaldehyde production by lactose-fermenting organisms, such as E.coli, produce characteristic red colonies with a pink surrounding area, marked by its reaction with Sodium sulphite in the presence of Basic fuchsin, a pH indicator. Lactose non-fermenters form colorless, transparent colonies. For the enumeration of coliform bacteria employ sample dilutions, which yield between 10 - 50 coloniesper plate using the pour plate method. Therefore, several dilutions should be made in the melted medium, poured and once gelled, incubated at 35 ± 2°C for 18 - 24 hours. The coliform colonies have anintensely red center zone surrounded by a pink halo sharply outlined against the uniformly blue background of the medium. Salmonella spp.which do not ferment Lactose, produce colorless to pale pink colonies. The medium is sensitive to light, which reduces its effectiveness and changes its color fromstrong blue to purple or pink. The medium should be prepared immediately before use and, if necessary,stored in the dark for as little time as possible.