Brilliant Green Bile Agar, 500 g

Brilliant Green Bile Agar was originally formulated by Nobel and Ponney (1) for enumeration of coliform bacteria from materials of sanitary importance. Subsequently APHA approved the medium for the estimation of coliforms in test samples of various materials (2, 3). The medium contains a combination of brilliant green and oxgall, which is highly selective for coliforms, inhibiting most of the gram-positive bacteria including lactose fermenting Clostridia (4) and some gram-negative bacteria. Erioglaucine and basic fuchsin together form the indicator system of the medium. When the pH is neutral, color of the medium is blue while acid production from lactose turns the medium pink and colonies appear pink to deep red depending on the pH change. Colonies of coliform bacteria are deep red surrounded by a pink halo against blue background of the medium. It is recommended that the medium be prepared just prior to use and if the medium has to be stored, it should be kept in dark. Brilliant Green Bile Agar medium is sensitive to light, particularly direct sunlight. Direct exposure may exhibit a decrease in the productivity of the medium and also the color of the medium may change from deep blue to purple or red. Storage and Shelf-life: Store below 30°C in tightly closed container and the prepared medium at 2 - 8°C. Use before expiry date on the label. References: 1. Noble and Tonney, 1935, J. Am. Waterworks Assoc., 27:108. 2. Downes F. P. and Ito K., (Eds.), 2001, Compendium of Methods for the Microbiological Examination of Foods, 4th Ed., APHA, Washington, D.C. 3. Greenberg A. E., Eaton A. D., and Clesceri L. S., (Eds.), 1998, Standard Methods for the Examination of Water and Wastewater, 20th Ed., APHA, Washington, D.C. 4. McCrady and Langerin, 1932, J. Dairy Science, 15:321