Dehydrated culture media
R2A Agar w/o Agar
For the total aerobe count in treated waters.
- Cat. No.
- LC-1470
- Category
- Dehydrated culture media
- Format
- 500 g
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
R2A Agar w/o Agar was developed by Reasoner and Geldreich for bacteriological plate counts of treated potable water, being able to recover the stressed chlorine-treated bacteria. Nutritionally rich media suppress these slow-growing bacteria, whereas a low nutrient medium, such as R2A Agar w/o Agar, in combination with a lower incubation temperature and longer incubation time, stimulates the growth of stressed and chlorine-tolerant bacteria.
Key features
Applications
Non-selective enumeration of mesophilic aerobes.
Industry
Water.
Preparation
3.12 g in one liter of distilled water; boil for one minute, dispense and sterilize in autoclave at 121 °C for 15 minutes.
Principles and uses
Proteose peptone and casein hydrolysate provide nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is the source of vitamins, particularly of the B-group. Dextrose is a source of fermentable carbohydrate as an energy source; starch absorbs toxic metabolic by-products and thereby aids the recovery of injured organisms. Sodium pyruvate increases the recovery of stressed cells. Magnesium sulfate provides divalent cations and sulfate. Dipotassium phosphate is used to balance the pH and provide phosphate.
Technical specifications
| Solubility | Without residues |
|---|---|
| Appearance | Fine powder |
| Color of the dehydrated medium | Beige |
| Color of the prepared medium | Amber |
| Final pH (25 °C) | 7.2 ± 0.2 |
| Amount per litre | 3.12 g |
| Storage | 2 to 25 °C |
Formula
| Ingredient | g/L |
|---|---|
| Glucose | 0.5 |
| Dipotassium phosphate | 0.3 |
| Proteose peptone | 0.5 |
| Sodium pyruvate | 0.3 |
| Starch | 0.5 |
| Yeast extract | 0.5 |
| Casein hydrolysate | 0.5 |
| Magnesium sulfate anhydrous | 0.024 |
Typical formula in g/L, adjusted and/or supplemented as required to meet performance criteria.
Preparation and use
Preparation
Suspend 3.12 grams of the medium in one liter of distilled water. Mix well and dissolve by heating with frequent agitation. Boil for one minute until complete dissolution. Dispense into appropriate containers and sterilize in autoclave at 121 °C for 15 minutes. Cool to 50 °C and mix well.
Instructions for use
Inoculate and incubate at 35 ± 2 °C for 24-72 hours.
Quality control
Microbiological test
Incubation conditions: 35 ± 2 °C / 24-72 h.
| Microorganism | Specification |
|---|---|
| Escherichia coliATCC 11775 | Good growth |
| Staphylococcus epidermidisATCC 12228 | Good growth |
| Escherichia coliATCC 25922 | Good growth |
| Staphylococcus aureusATCC 25923 | Good growth |
| Staphylococcus aureusATCC 6538 | Good growth |
| Bacillus subtilisATCC 6633 | Good growth |
| Escherichia coliATCC 8739 | Good growth |
| Pseudomonas aeruginosaATCC 9027 | Good growth |
Bibliography
- American Public Health Association (1985) Standard Method for the Enumeration of Water and Wastewater.
- European Pharmacopoeia 7.0.
What you receive
The product
Shipped under controlled temperature when the product requires it.
Lot certificate
Every lot comes with its certificate.
Tracked shipment
Follow your shipment live, from our warehouse to your lab.
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