VIOLET RED BILE AGAR

The coliform group consists of several genera of bacteria belonging to the family Enterobacteriaceae. The historical definition of this group has been based on the method used for detection i.e. lactose fermentation. This group is defined as all aerobic and facultative anaerobic, gram-negative, non-spore-forming rod shaped bacteria that ferment lactose with gas and acid formation within 48 hour at 35?C. Examination of foods, ingredients and raw materials, for the presence of marker groups such as coliforms is the one of the common tests.
Violet Red Bile Agar, a modification of MacConkey original formulation is used for the enumeration of coli-aerogenes bacterial group. It relies on the use of the selective inhibitory components crystals violet and bile salts and the indicator system lactose, and neutral red. Thus, the growth of many unwanted organisms is suppressed, while tentative identification of sought bacteria can be made

for isolation and enumeration of coli-aerogenes in water, milk and other dairy food products