CALDO PA GRANULADO (PRESENÇA AUSÊNCIA) SEG US-EPA MERCK (EMB 500G)

CALDO PA GRANULADO (PRESENCE ABSENCE BROTH) SEG US-EPA MERCK RENDIMENTO 91,5G/L P/ PRESENÇA/AUSENCIA Embalagem 500g. The culture medium conforms with the recommendations of standard methods (US-EPA) for the examination of water. Mode of Action Peptones and meat extract give the nutrients and trace elements required for growth whereas the phosphate buffer and sodium chloride provide a good buffering capacity and the osmotic equilibrium. Lactose-fermenting organisms form acid which is identified by the pH indicator bromocresol purple as a colour change from purple to yellow. The selective component of the culture medium is sodium lauryl sulphate which largely inhibits the undesired accompanying flora - with the exception of the coliforms. Typical Composition (g/litre): (single strength) Meat extract 3.0; peptones 5.0; lactose 7.46; tryptose 9.83; dipotassium hydrogenphosphate 1.35; potassium dihydrogenphosphate 1.35; sodium chloride 2.46; sodium lauryl sulphate 0.05; bromocresol purple 0.0085. Preparation For the preparation of the triple strength concentrated broth, completely dissolve 91.5 g in 1 litre of demin water. Fill 50 ml quantities in 250 ml milk dilution bottles with screw caps and autoclave for 12 min. at 121 °C. Allow broth to cool to room temperature. The pH of the single-strength broth: 6.8 ± 0.2 at 25 °C. The prepared medium is clear to slightly opalescent and purplered.