Violet Red Bile Agar A1 Quality – HX-Media

Violet Red Bile Agar – HX-Media

Product Overview

Violet Red Bile Agar (VRBA) is a selective and differential culture medium specifically formulated for the enumeration and detection of coliform bacteria in food, dairy products, water, and other samples of sanitary importance.

The medium is widely used in food microbiology and quality control laboratories as a standard method for coliform testing, complying with internationally recognized standards such as ISO, APHA, and FDA BAM methods.

Violet Red Bile Agar contains bile salts and crystal violet, which selectively inhibit the growth of Gram-positive bacteria, thereby allowing the growth of Gram-negative enteric organisms, particularly coliforms such as Escherichia coli, Enterobacter spp., and Klebsiella spp.

The differential capability of the medium is based on lactose fermentation. Coliform bacteria ferment lactose to produce acid, leading to a decrease in pH. This pH change is detected by the neutral red indicator, which turns colonies red to purple. Lactose-fermenting coliforms typically form reddish colonies surrounded by a zone of precipitated bile salts, providing a clear visual distinction.

The inclusion of agar at appropriate concentration ensures optimal colony development and allows the use of pour plate or overlay techniques, which are essential for accurate enumeration in heavily contaminated samples.

Due to its high selectivity, clarity of results, and reliability, Violet Red Bile Agar is extensively used in routine microbiological analysis, hygiene monitoring, and regulatory compliance testing.

🔬 Key Features