main product photo

Dichloran Medium Base w/ Rose Bengal, Granulated

0 Review
As low as $215.60
Availability: Out of stock
Notify me when the price drops User
Availability: In stock
Only %1 left
SKU:
GM1000
For selective isolation and enumeration of yeasts and moulds associated with food spoilage.

Composition**

Ingredients Gms / Litre
Peptic digest of animal tissue 5.000
Dextrose 10.000
Monopotassium phosphate 1.000
Magnesium sulphate 0.500
Rose bengal 0.025
Dichloran 0.002
Agar 15.000
Final pH (at 25°C) 5.6±0.2

**Formula adjusted, standardized to suit performance parameters

Directions

Suspend 15.76 grams in 500 ml distilled water. Heat to boiling to dissolve the medium completely. Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes. Cool to 45-50°C and aseptically add sterile reconstituted contents of 1 vial of Chloramphenicol Selective Supplement (FD033). Mix well and pour into sterile Petri plates.

Principle And Interpretation

Dichloran Medium Base with Rose Bengal is formulated as described by King et al (1), which is a modification of Rose Bengal Chloramphenicol Agar (2). Dichloran Medium Base with Rose Bengal is used along with Rose Bengal Chloramphenicol Agar where it is necessary to enumerate yeasts in the presence of moulds.

Peptic digest of animal tissue provides nitrogen, vitamins and minerals. Dextrose is a carbohydrate source. Phosphate buffers the medium. Magnesium sulfate provides divalent cations and sulfate. Dichloran is an antifungal agent, added to the medium to reduce colony diameters of spreading fungi. Rose bengal exhibits an improved inhibitory activity at pH 5.6 and therefore the final pH of the medium is reduced to 5.6 for the inhibition of spreading fungi (1). The presence of rose bengal in the medium suppresses the growth of bacteria and restricts the size and height of colonies of the more rapidly growing moulds. The concentration of rose bengal is reduced for optimal performance with dichloran. Additionally, rose bengal is taken up by yeast and mold colonies, which allows these colonies to be easily recognized and enumerated.

Add 40 ml of food sample to 200 ml of 0.1% Peptone water (M028) and shake periodically for 30 minutes (3) or process in stomacher for 30 seconds (4). Inoculate 0.1 ml of this sample on Dichloran Medium Base with Rose Bengal. Report the number of colonies per gram of food.

Quality Control

Appearance: Light yellow to pink coloured granular medium

Gelling: Firm, comparable with 1.5% Agar gel

Colour and Clarity of prepared medium: Pink coloured, clear to slightly opalescent gel forms in Petri plates

Reaction: Reaction of 3.15% w/v aqueous solution at 25°C. pH : 5.6±0.2

pH: 5.40-5.80

Cultural Response

Cultural characteristics observed with added Chloramphenicol Selective Supplement (FD033), after an incubation at 25-30°C for upto 6 days.

Organism Inoculum (CFU) Growth Recovery
Bacillus subtilis ATCC 6633 >=10³ inhibited 0%
Candida albicans ATCC 10231 50-100 good-luxuriant >=50%
Escherichia coli ATCC 25922 >=10³ inhibited 0%
Mucor racemosus ATCC 42647 50-100 good-luxuriant
Saccharomyces cerevisiae ATCC 9763 50-100 good-luxuriant >=50%

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.

Reference

  1. King D.A. Jr., Hocking A.D. and Pitt J.I., 1979, J. Appl. Environ. Microbiol., 37:959.
  2. Jarvis B., 1973, J. Appl. Bact., 36:723.
  3. Sharf J.M. (Ed.), 1966, American Public Health Association, 2nd ed., New York.
  4. Sharp A.N. and Jackson A.K., 1972, J. Appl. Bact., 24:175.
More Information
Product Name Dichloran Medium Base w/ Rose Bengal, Granulated
SKU GM1000
Product Type Granulated
Physical Form Granular
Origin Animal
Packaging type HDPE
References 1. King D.A. Jr., Hocking A.D. and Pitt J.I., 1979, J. Appl. Environ. Microbiol., 37:959.2.Jarvis B., 1973, J. Appl. Bact., 36:723.3.Sharf J.M. (Ed.), 1966, American Public Health Association, 2nd ed., New York.4.Sharp A.N. and Jackson A.K., 1972, J. Appl. Bact., 24:175.
Customized Product Available No
Write Your Own Review
You're reviewing:Dichloran Medium Base w/ Rose Bengal, Granulated

Related Products