Specifications
Ingredients : gms/lit.Peptone 10.00Lactose 10.00Dipotassium phosphate 3.50Sodium sulphite 2.50Basic fuchsin 0.50Agar 15.00Final pH (at 25°C) : 7.5 + 0.2Instrustion for use :Suspend 41.5 grams in 1000 ml distilled water. Heat to boiling to dissolve the mediumcompletely. Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes. Mix well beforepouring into sterile Petri plates. If the solidified culture medium is somewhat too red, then toremove the colour add a few drops (max. 1 ml/litre) of a freshly prepared 10% Sodium sulphitesolution and boil.Principle :The medium contains peptone which provide nitrogen, carbon, vitamins and minerals required forbacterial growth. Sodium sulphite and basic fuchsin make this medium selective by suppressinggram-positive organisms. Coliforms produce pink colonies on fermentation of lactose while lactosenon-fermenters produce colourless colonies on the medium. With Escherichia coli, this reaction isvery pronounced as the fuchsin crystallizes, exhibiting a permanent greenish metallic luster(fuchsin luster) to the colonies.