Liofilchem® Brilliant Green Bile Broth 2%

Liofilchem® Brilliant Green Bile Broth 2% is a selective liquid medium used for the detection and confirmation of coliform organisms in water, wastewater, dairy products, and food samples of sanitary significance.

The formulation complies with APHA, ISO 4831, and ISO 4832 standards for coliform enumeration and provides a reliable method for monitoring microbiological quality in environmental and food hygiene testing programs.

Key Features

• Conforms to international standards: prepared according to APHA and ISO 4831 / 4832 protocols.
• Selective for coliforms: brilliant green dye and ox bile inhibit Gram-positive bacteria and non-coliform Gram-negatives.
• Differential by gas production: gas formation in Durham tubes indicates lactose fermentation by coliforms.
• Versatile format: available as dehydrated powder, ready-to-use tubes, and bottles (single or double strength).
• Validated for food, water, and dairy testing laboratories.

Principle of the Method

• Enzymatic digest of casein provides amino acids, nitrogen, and growth factors.
• Lactose is the fermentable carbohydrate that supports coliform metabolism.
• Ox bile and brilliant green dye selectively inhibit non-coliform organisms.
• Gas formation within the Durham tube signifies lactose fermentation by Escherichia coli and other coliforms.
• Final pH 7.2 ± 0.2 ensures optimal selectivity and metabolic activity.

Typical Formula (per litre)

Preparation

Dehydrated Medium

1. Suspend 40 g of powder in 1 L of distilled water for single strength or 80 g for double strength broth.
2. Heat to boil with frequent shaking until completely dissolved.
3. Dispense 10 mL aliquots into tubes containing Durham gas collecting tubes.
4. Sterilize at 121 °C for 15 min.

Ready-to-Use Medium (in Bottles/Tubes)

Aseptically dispense into Durham fitted tubes or bottles as required.

Test Procedure

1. Detection: Inoculate 1 mL of sample (diluted or undiluted) into Brilliant Green Bile Broth 2%. Use double strength for large sample volumes.
2. Confirmation: Subculture from presumptive positive tests (e.g. Lauryl Sulphate Tryptose Broth or VRBL Agar).
3. Incubation:
   – 44 ± 1 °C for 48 h to detect E. coli production.
   – 30 °C or 37 °C for 24–48 h for general coliform enumeration (ISO recommendation).
4. Observe for turbidity and gas production as positive indicators.

Interpretation of Results

Quality Control

Appearance (Dehydrated): Free-flowing, homogeneous, green-beige powder

Appearance (Prepared): Clear green liquid

Storage and Stability

• Store powder at 10–30 °C, dry and tightly sealed.
• Store prepared tubes/bottles at 10–25 °C, away from light.
• Shelf Life: 4 years (dehydrated); 2 years (tubes/bottles).
• Discard if contaminated, caked, or expired.

Safety and Handling

• Not classified as hazardous under current legislation.
• For professional laboratory use only by trained operators.
• Consult the Safety Data Sheet (SDS) for safe handling practices.
• Dispose of used materials according to local biosafety regulations.

Ordering Information

Liofilchem® Brilliant Green Bile Broth 2% is an internationally standardized liquid culture medium for coliform detection and confirmation in food, water, and environmental testing. Its selective formulation—with ox bile and brilliant green—ensures suppression of non-target organisms, while lactose fermentation and gas formation provide a clear, rapid indication of coliform presence. This medium remains a cornerstone for laboratories following ISO and APHA protocols in microbiological quality assurance.