BLOOD AGAR BASE, IMPROVED (7268)
Intended Use
Blood Agar Base, Improved is used with blood for the isolation and cultivation of a wide variety of fastidious
microorganisms.
Product Summary and Explanation
Blood agar bases are typically supplemented with 5 - 10% sheep, rabbit, or horse blood for use in isolating,
cultivating, and determining hemolytic reactions of fastidious pathogenic microorganisms. Without enrichment,
blood agar bases can be used as general purpose media.
In 1919, Brown experimented with blood agar formulations for the effects of colony formation and hemolysis.1
In Blood Agar Base, Improved, the formula was modified slightly to enhance organism growth and neutralize
any toxic metabolites. Blood Agar Base media are specified in standard method procedures for food testing.2-4
Principles of the Procedure
Nitrogen, vitamin, and carbon sources are provided by Enzymatic Digest of Casein and Enzymatic Digest of
Animal Tissue in Blood Agar Base, Improved. Yeast Extract is a vitamin source. Corn Starch is added to
ensure any toxic metabolites produced are absorbed, and enhance organism growth.5
Sodium Chloride
maintains the osmotic balance of the medium. Agar is the solidifying agent.
Formula / Liter
Enzymatic Digest of Casein .................................................... 15 g
Enzymatic Digest of Animal Tissue........................................... 4 g
Yeast Extract............................................................................. 2 g
Corn Starch............................................................................... 1 g
Sodium Chloride ....................................................................... 5 g
Agar ........................................................................................ 14 g
Final pH: 7.0 ± 0.2 at 25C
Formula may be adjusted and/or supplemented as required to meet performance specifications.
Precautions
1. For Laboratory Use.
2. IRRITANT. Irritating to eyes, respiratory system, and skin.
Directions
1. Suspend 42 g of the medium in one liter of purified water.
2. Heat with frequent agitation and boil for one minute to completely dissolve the medium.
3. Autoclave at 121C for 15 minutes.
4. Prepare 5 - 10% blood agar by aseptically adding the appropriate volume of sterile defibrinated blood to
melted sterile agar medium, cooled to 45 - 50C.
Quality Control Specifications
Dehydrated Appearance: Powder is homogeneous, free flowing, and light beige.
Prepared Appearance: Prepared medium without blood (plain) is trace to slightly hazy and yellow-beige. With
5% sheep blood, medium is red and opaque.