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R2A Agar

R2A Agar is used for the enumeration and cultivation of bacteria from potable water in a laboratory setting. R2A Agar is not intended for use in the diagnosis of disease or other conditions in humans.

R2A Agar was developed by Reasoner and Geldreich for bacterial plate counts of treated potable water. R2A Agar is a low nutrient medium, and in combination with a lower incubation temperature and longer incubation time, stimulates the growth of stressed and chlorine-tolerant bacteria. Nutritionally rich media support the growth of fast-growing bacteria, and may suppress slow growing or stressed bacteria found in treated water. When compared with Tryptone Glucose Yeast Extract Agar or Standard Methods Agar, R2A Agar reported improved recovery of stress and chlorine-tolerant bacteria from drinking water systems.

R2A Agar is recommended in standard methods for pour plate, spread plate, and membrane filter methods for heterotrophic plate counts.

 

Formula Liter
Enzymatic Digest of Casein 0.25 g
Enzymatic Digest of Animal Tissue (Proteose Peptone) 0.25 g
Acid Hydrolysate of Casein 0.5 g
Yeast Extract 0.5 g
Dextrose (Glucose) 0.5 g
Soluble Starch 0.5 g
Dipotassium Phosphate 0.3 g
Magnesium Sulfate Heptahydrate 0.05 g
Sodium Pyruvate 0.3 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.

Directions

  1. Suspend 18.2 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.

Order Details

Product # Product Description
7390A R2A Agar, 500 g
7390C R2A Agar, 10 kg