This medium is recommended for selective isolation, detection and enumeration of coli-aerogenes bacteria in water, milk and other dairy, food products. It relies on the use of the selective inhibitory components crystals violet and bile salts and the indicator system lactose, and neutral red. Selectivity of VRBA can be increased by incubation under anaerobic conditions and/ or at elevated temperature, i.e. equal to or above 42°C.