Ingredients : gms/lit.Tryptone 10.00Beef extract 5.00Yeast extract 1.00Glycine 12.00Sodium pyruvate 10.00Lithium chloride 5.00Agar 20.00Final pH (at 25°C) : 7.0 + 0.2Directions :Suspend 63.0 grams in 950 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 50°C and aseptically add50 ml concentrated Egg Yolk Emulsion (BF003) and 3 ml sterile 3.5% Potassium Tellurite solution(BF008) or 50 ml Egg Yolk Tellurite Emulsion (BF007). Mix well and pour into sterile petri plates.Principle :Tryptone, Beef extract and yeast extract are sources of nitrogen, carbon, sulphur and vitamins.Sodium pyruvate not only protects injured cells and helps recovery but also stimulates Staphylococcusaureus growth without destroying selectivity. Lithium chloride and potassium tellurite inhibit most ofthe contaminating microflora except Staphylococcus aureus. The tellurite additive is toxic to egg yolkclearingstrains other than S.aureus and imparts a black colour to the colonies. With the addition ofegg yolk, the medium becomes yellow, opaque. Proteolytic bacteria produce a clear zone aroundcolony in egg yolk containing media. A clear zone and grey-black colonies on this medium arediagnostic for coagulase positive Staphylococci. Upon further incubation, an opaque zone is developedaround colonies which can be due to lipolytic activity.