Technical Data
Mannitol Salt Agar (Powder)
Microbiological Grade
Storage RT    Shipping RT
Components shown as g/liter
Sodium Chloride75.0
Pancreatic Digest of Casein5.0
Peptic Digest of Animal Tissue5.0
Beef Extract1.0
Phenol Red0.025
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.

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 15-30 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 refrigerated and used within a short period of time.

Appearance: Pale pinkish beige to beige free-flowing powder.

Solubility: Clear to slightly hazy, yellowish to light pink and complete Cultural Response

Important Note: This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.

J. Bacteriology, 50:201 (1945)
“Manual of Clinical Microbiology”, 3rd Ed., Amer. Soc. for Microbiology., Wash. D.C. (1980)