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Vogel and Johnson Agar

Vogel and Johnson Agar is used for the isolation of staphylococci in a laboratory setting. Vogel and Johnson Agar is not intended for use in the diagnosis of disease or other conditions in humans.

Coagulase-positive staphylococci, primarily Staphylococcus aureus, are among the microorganisms that cause spoilage or chemical changes in cosmetic products. To isolate coagulase-positive, mannitol fermenting staphylococci, Vogel and Johnson modified Tellurite-Glycine Agar by Zebovitz, Evans, and Niven. The modification included increasing mannitol and adding a pH indicator. Vogel and Johnson Agar selects and differentiates coagulase-positive staphylococci that ferment mannitol and reduce tellurite.

Vogel and Johnson (VJ) Agar is specified in standard methods testing for cosmetics and nutritional supplements.

 

Formula Liter
Enzymatic Digest of Gelatin 10 g
Yeast Extract 5 g
Mannitol 10 g
Dipotassium Phosphate 5 g
Lithium Chloride 5 g
Glycine 10 g
Phenol Red 0.025 g
Agar 15 g

Final pH: 7.2 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.

Supplement

Tellurite Solution (1%) Chapman, 10 mL
Potassium Tellurite, 100 mg

Directions

  1. Suspend 60 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 121°C for 15 minutes.
  4. After cooling to 45 – 50°C add 2 vials (20 mL) of Tellurite Solution (1%) Chapman Supplement (7989) or 20 mL of a sterile 1% Potassium Tellurite Solution. Note: Do not heat medium after Tellurite Solution has been added.
  5. Mix thoroughly before dispensing.

Order Details

Product # Product Description
7207A Vogel and Johnson Agar, 500 g
7207B Vogel and Johnson Agar, 2 kg
7207T Vogel and Johnson Agar, 5 kg