Coliforms and E. coli · Confirmation of coliforms
Brilliant Green Lactose Bile Broth – confirmation of coliforms
Brilliant Green Lactose Bile Broth (BGLB) is the confirmation broth for coliforms in the MPN method. Positive LST tubes are subcultured into BGLB, and gas production after incubation confirms coliforms.
- Confirmation broth for coliforms
- Bile and brilliant green inhibit Gram-positive flora
- Gas in Durham tube = confirmed coliforms
How Brilliant Green Lactose Bile Broth works
Ox bile and brilliant green suppress Gram-positive bacteria and many non-coliform Gram-negative bacteria. Lactose fermentation with gas, collected in an inverted Durham tube, confirms the presence of coliforms. The number of positive tubes gives the MPN value from the table.
Typical reactions
| Organism | Reaction |
| Coliforms | Turbidity and gas |
| Enterococcus faecalis | No gas |
Technical data
| Preparation | 40 g/L; boil to dissolve, dispense into tubes with Durham tubes, autoclave 121 °C 15 min |
| Final pH | 7.2 ± 0.2 |
| Incubation | 35-37 °C, 24 h |
| Storage | Dry, dark place; keep the container tightly closed |
| Shelf life | 3 years |
Applications and practical notes
In the multiple-tube (MPN) method for coliforms and E. coli, as described in FDA BAM Chapter 4 and ISO 4831, a presumptive broth is followed by confirmation broths. Typical applications include:
- Coliform and E. coli MPN counts in food and feed
- Testing of water, ice and beverages
- Hygiene monitoring in dairy, meat and ready-to-eat production
- Verification of media and methods with reference strains
Working with Brilliant Green Lactose Bile Broth: Subculture from every gas-positive LST tube with a loop, incubate for the time stated in your method and read gas at the end of incubation.
Good practice with dehydrated media: keep the bottle tightly closed in a cool, dry place, weigh the powder quickly to avoid moisture uptake, and use fresh distilled or deionised water. Check the pH of each new batch after preparation and before use, and label prepared media with the date. Performance of each lot can be verified with reference strains according to ISO 11133, the standard for the preparation, production, storage and performance testing of culture media.
About the Salmonella culture method: the reference method for Salmonella in the food chain, ISO 6579-1, has four steps: non-selective pre-enrichment, selective enrichment in two broths, plating on two selective agars and confirmation of typical colonies. The FDA BAM Chapter 5 follows the same principle with media adapted to different food types. Rapid tests and identification kits shorten the time to result, but positive screening results are usually confirmed by the culture method. COLO.Science offers products for every step, so that one supplier covers the whole procedure.
Complete sets from one supplier: COLO.Science supplies culture media, supplements, rapid tests, identification kits and QC strains as complete sets for the method you follow. Send us your sample types and standards, and we will prepare an offer with the matching products and documentation.
Brilliant Green Lactose Bile Broth is supplied by COLO.Science in the pack sizes listed under Ordering information. For larger quantities, regular deliveries or method-specific sets that include Brilliant Green Lactose Bile Broth, please send us a request. With every delivery of Brilliant Green Lactose Bile Broth you receive the lot number and expiry date, and on request we send the available documentation for Brilliant Green Lactose Bile Broth.
Where Brilliant Green Lactose Bile Broth fits in coliform and E. coli testing
- Presumptive test – Lauryl Sulfate Tryptose Broth (MPN) or VRBL / chromogenic agar (colony count)
- Confirmation – BGLB Broth for coliforms; EC or EC-MUG Broth at 44.5 °C for E. coli
- Isolation – EMB, MacConkey, TBX or chromogenic E. coli agar
- Identification – IMViC kit; for O157 and STEC: SMAC or chromogenic O157 agar, latex and PCR
Ordering information
| Product | COLO code | Pack |
|---|---|---|
| Brilliant Green Lactose Bile Broth (BGLB) | PRO7430 | 500 g |
Product notice: preparation, storage conditions and shelf life are given on the label. Technical data on this page are for orientation; the label and the lot documentation apply. B2B prices are quoted net, excluding VAT.
Sales and technical support
COLO LabExperts
Polje ob Sotli 4, SI-3255, Slovenia
Quotations and technical support for culture media and microbiology products across our international sales territory. B2B prices are net, excluding VAT.
COLO.SCIENCE | MICROBIOLOGY SUPPORT
Need the complete set for your method?
Send the sample type, target organism and the standard you follow. COLO.Science will put together the media, supplements, QC strains and confirmation tests for the whole procedure.
