TOTAL COLIFORM BACTERIA Media Violet Red Bile Agar(Cm107-Oxoid) Media Preparation Dissolve 385gm in 1 litre of distilled water by bringing to the boil. Allow to cool to 45-50C. The media can be held at this temperature for a maximum of 3 hours Do not autoclave this material Method Pipette Iml of the 10% homogenate onto a sterile petri dish, add 10mls of freshly prepared cooled agar, swirl to mix and allow to set. Incubate upside down at 37'C for 48 hours After incubation count the red colonies and multiply by 10 to give count per gm YEASTS AND MOULDS Media Rose Bengal Agar(CM49-Oxoid Chloramphenicol Supplement (SRT8-Oxoid) dia Preparation Dissolve 16gm of agar in 500ml of distilled water by bringing to the boil Sterilize at 121'C for 15 minutes and allow to cook to 50C. add the contents of 1 vial of supplement which has been dissolved in 2ml of acetone. Pour 10ml of agar onto sterile plates and store at 5'C Method Pipette 0. 2ml of the homogenate onto a prepared plate and spread over the surface of the agar using a sterile glass spreader. The spreader can be sterilized by flaming between use The plate should be incubated upside down at 22"C+ 2C for 4-5 days Inspect the plate daily after 3 days as vigorous mould growth may make counting difficult Count moulds(rough, hairy, fungal appearance)multiply by 50 to give umber of moulds per gm Count yeasts(smooth surfaced colonies)and similarly multiply by 50T O T A L C O L I F O R M BACTERIA Media Media Preparation Dissolve 38.5gm in 1 litre of distilled water by bringing to the boil. Allow to cool to 45-50°C. The media can be held at this temperature for a maximum of 3 hours. Violet Red Bile Agar (Cm107 - Oxoid) Do not autoclave this material. Method Pipette lml of the 10% homogenate onto a sterile petri dish, add lOmls of freshly prepared cooled agar, swirl to mix and allow to set. Incubate upside down at 37°C for 48 hours. After incubation count the red colonies and multiply by 10 to give count per gm. YEASTS AND MOULDS Media Rose Bengal Agar (CM49 - Oxoid) Chloramphenicol Supplement (SRT8 - Oxoid) Media Preparation Dissolve 16gm of agar in 500ml of distilled water by bringing to the boil. Sterilize at 121°C for 15 minutes and allow to cook to 50°C. Add the contents of 1 vial of supplement which has been dissolved in 2ml of acetone. Pour 10ml of agar onto sterile plates and store at 5°C. Method Pipette 0.2ml of the homogenate onto a prepared plate and spread over the surface of the agar using a sterile glass spreader. The spreader can be sterilized by flaming between use. The plate should be incubated upside down at 22°C -t 2°C for 4-5 days. Inspect the plate daily after 3 days as vigorous mould growth may make counting difficult. Count moulds (rough, hairy, fungal appearance) multiply by 50 to give number of moulds per gm. Count yeasts (smooth surfaced colonies) and similarly multiply by 50. 24%