M-BCG Yeast and Mould Broth

M-BCG Yeast and Mould Broth is used for the detection of fungi in routine analysis of beverages using membrane filter technique.

Composition**

Final pH (at 25°C): 4.6±0.2

**Formula adjusted, standardized to suit performance parameters

Directions

Suspend 7.32 grams in 100 ml distilled water. Heat if necessary to dissolve the medium completely. Dispense and sterilize by autoclaving at 118-121°C for 10 minutes(12-15 lbs pressusre).

Principle And Interpretation

M-BCG (Bromo Cresol Green) Yeast and Mould Broth is used for detecting fungi in routine analysis of beverages using membrane filter technique (1). It is a modification of M-Yeast and Mould Broth used for detection of fungi in sugar and other materials.

The medium is highly nutritious for the growth of yeasts and moulds. Biopeptone and yeast extract provide nitrogenous compounds and vitamin B complex. Thiamine is also a B vitamin in the medium. Dextrose acts as the energy source. Diastase is a mixture of amylolytic enzymes. Bromo cresol green is the pH indicator which is green at acidic pH (pH 4.0) while blue at pH 5.6. Potassium phosphate helps in maintaining buffering action in the medium. The low pH inhibits bacterial growth.

The membrane filter pad is saturated with 2.0 to 2.5 ml broth. Place the membrane filter used for filtration of test sample on the saturated pad and incubate at 30 -35°C for 48 hours.

Quality Control

Appearance: Cream to light green homogeneous free flowing powder

Colour and Clarity of prepared medium: Green coloured slightly opalescent solution, may contain a slight precipitate.

Reaction: Reaction of 7.32% w/v aqueous solution at 25°C. pH : 4.6±0.2

pH: 4.40-4.80

Cultural Response

M1130: Cultural characteristics observed after an incubation at 25-30°C for 48-72 hours.

Key: * - Formerly known as Aspergillus niger

Storage and Shelf Life

Store below 30°C in tightly closed container and use freshly prepared medium. Use before expiry date on the label.

Reference

1. MacFaddin J.F., 1985, Media for Isolation - Cultivation - Identification - Maintenance of Medical Bacteria, Vol.I, Williams and Wilkins, Baltimore.