OF Basal Medium , 500G , Himedia™
OF (Oxidation Fermentation) Basal medium is used for the determination of oxidative and fermentative metabolism of carbohydrates by gram-negative bacteria. Oxidative utilization of carbohydrate takes place when the medium is exposed to air i.e aerobic conditions while fermentative utilization occurs under anaerobic conditions by overlaying medium with mineral oil.
OF Basal Medium ( M395 )
Intended use
Recommended for differentiation of gram- negative bacteria from clinical and non-clinical samples on the basis of fermentative and oxidative metabolism of carbohydrates.
Composition**
Ingredients Gms / Litre
Tryptone 2.000
Sodium chloride 5.000
Dipotassium hydrogen phosphate 0.300
Bromo thymol blue 0.080
Agar 2.000
Final pH ( at 25°C) 6.8±0.2
**Formula adjusted, standardized to suit performance parameters
Directions
– Suspend 9.38 grams in 1000 ml purified/distilled water.
– Heat to boiling to dissolve the medium completely.
– Dispense in 100 ml amounts and sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes. To first 100 ml of sterile basal medium, aseptically add 10 ml of sterile 10% dextrose solution. To second 100 ml add 10 ml sterile 10% lactose solution. To third 100 ml add 10 ml sterile 10% saccharose solution.
– Mix and dispense 5 ml amounts aseptically into sterile tubes in duplicate for aerobic and anaerobic fermentation.
Quality Control
Appearance
Cream to greenish yellow homogeneous free flowing powder
Gelling
Semisolid, comparable with 0.2% Agar gel.
Colour and Clarity of prepared medium
Green coloured clear to slightly opalescent gel forms in tubes.
Reaction
Reaction of 0.94% w/v aqueous solution at 25°C. pH : 6.8±0.2
pH
6.60-7.00
Cultural Response
Cultural characteristics observed after an incubation at 35-37°C for 18-48 hours.
Storage and Shelf Life
Store between 10-30°C in a tightly closed container and the prepared medium at 20-30°C. Use before expiry date on the label.
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