Sterile MacConkey Broth is supplied by HiMedia. It is a sterile ready prepared media containing 100ml of purple coloured solution in bottles. MR-VP Broth (Glucose Phosphate Broth) is generally used for the selective enrichment of Escherichia coli in accordance with harmonized methods of USP, EP, BP, JP & IP. It is advisable to store this ready prepared media between 2-8C. Composition (in gm/L) is as follows:

Pancreatic digest of gelatin (20.00)

Lactose monohydrate (10.00)

Dehydrated Ox bile (5.00)

Bromo cresol purple (0.01)

MacConkey Broth is a modification of MacConkey Medium. Childs and Allen established the inhibitory effect of neutral red and therefore substituted it by the less inhibitory bromocresol purple dye. BCP is more sensitive in recording pH variation in the medium. MacConkey Broth is recommended for presumptive identification of coliforms and is prepared in accordance with the harmonized method of USP/EP/BP/JP. It is used as a presumptive test medium for coliforms in pharmaceutical products and other materials of sanitary importance. Pancreatic digest of gelatin provides essential growth nutrients and serves as a rich nitrogen source. Ox-bile inhibits gram-positive organisms. Lactose monohydrate is the fermentable carbohydrate. Bromo cresol purple is the pH indicator in the medium that turns yellow under acidic condition due to lactose fermentation.