Selective medium for isolation and enumeration of Staphylococci. Recommended by USP for microbial limit tests. S. aureus strains produce colonies surrounded by yellow zones due to the fermentation of mannitol. Acid production is indicated by the phenol red dye. Non-pathogenic Staphylococci produce colonies surrounded by red or purple zones and are smaller in size. Most common organisms (Gram negatives) are inhibited by the high salt content.
Appearance:Pale pinkish beige to beige free-flowing powder.
Solubility: Pale pinkish beige to beige free-flowing powder
Formulation Shown as g/liter:Sodium Chloride75.0Agar15.0D-Mannitol10.0Pancreatic Digest of Casein5.0Peptic Digest of Animal Tissue5.0Beef Extract1.0Phenol Red0.025Total: 111g/L
Directions per Liter:Dissolve 111 grams per liter of ddH2O, heating to boiling with stirring until completely solubilized. Dispense into appropriate containers, loosen caps and autoclave for 15 minutes at 121ºC (15psi).
Storage and Stability:Store powdered media at RT. Opened bottles should be capped tightly and kept in a dark, low humidity environment. Prepared media should be kept at 4°C and used within a short period of time.