Violet Red Bile Glucose Agar (VRBGA) is a selective medium for the isolation and enumeration of Enterobacteriaceae in food products. It is a modification of the original Violet Red Bile Agar with the lactose being replaced with glucose. As all Enterobacteriaceae ferment glucose VRBGA allows for a wider range of organisms to be detected. This medium conforms to the requirements of the Harmonised USP/EP/JP.
Yeast extract and pancreatic digest of gelatin provide the required carbon, nitrogen and vitamins. Glucose is a fermentable carbohydrate and neutral red is a pH indicator. Sodium chloride maintains the osmotic balance. The medium is made selective by the inclusion of bile salts and crystal violet to inhibit Gram-positive and non-enteric organisms.
Violet Red Bile Glucose Agar
Additional Information
| Shelf Life (days) | |
|---|---|
| Storage Temp (°C) | |
| Dehydrated Medium Appearance | |
| Prepared Medium Appearance | |
| Dehydrated Medium Colour | |
| Prepared Medium Colour | |
| Dehydrated PH | |
| Prepared PH | |
| Recommended Incubation |
Product Description
| Organisms | Ref. No | Result |
| Escherichia coli | ATCC 8739 | Growth, red/purple colonies with or without precipitation halo |
| Salmonella typhimurium | ATCC 14028 | Growth, red/purple colonies with or without precipitation halo |
| Enterococcus faecalis | ATCC 29212 | Inhibited |
Formula*
| g/L | |
| Yeast extract | 3.0 |
| Pancreatic digest of gelatin | 7.0 |
| Sodium chloride | 5.0 |
| Bile salts | 1.5 |
| Glucose | 10.0 |
| Neutral red | 0.03 |
| Crystal violet | 0.002 |
| Agar | 12.0 |
| Total | 38.5 |
| *Adjusted/supplemented as required to meet performance requirements |
Preparation
Suspend 38.5g of the medium in one litre of deionised / purified water. Allow the medium to soak whilst mixing for 10 minutes. Heat with frequent agitation and boil for one minute to completely dissolve the medium. Cool to 45-50°C and aseptically dispense into appropriate sterile containers.