VIOLET RED BILE GLUCOSE AGAR (USP/EP/JP/BP/IP)

Violet Red Bile Dextrose Agar is a selective medium used for the detection and enumeration of Enterobacteriaceae, particularly bile-tolerant Gram-negative bacteria, from non-sterile pharmaceutical products. The medium is appropriate for selective subculture and recovery in microbial limit testing in balanced USP/EP/BP/JP/IP methods. Inclusion of glucose supports growth of fastidious Enterobacteriaceae and the recovery of organisms from adverse conditions.
Gelatin peptone and yeast extract provide nitrogenous and carbonaceous compounds, amino acids, vitamins and other nutrients necessary for bacterial metabolism. The fermentable carbohydrate is glucose, while neutral red is employed to indicate acid production by a visible colour change. Enterobacteriaceae such as Escherichia coli and Salmonella ferment glucose and produce acid that lowers the pH and produces pink colonies. Higher acid production may cause precipitation of bile salts around the colonies.
Bile salts and crystal violet impart selective action against numerous Gram-positive bacteria. Non-glucose fermenting bile tolerant organisms like Pseudomonas aeruginosa may appear as colourless colonies without bile precipitation. Sodium chloride contributes to the osmotic balance.

Designed for detecting and enumerating Enterobacteriaceae from pharmaceutical products, with selective recovery of bile-tolerant Gram-negative bacteria under harmonized microbial limit testing methods.