Dehydrated culture media
Yeast Extract Soy Agar
For the selective isolation of dermatophytes and other pathogenic fungi.
- Cat. No.
- LC-1097
- Category
- Dehydrated culture media
- Format
- 500 g
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
Yeast Extract Soy Agar is used for the selective isolation of dermatophytes and other pathogenic fungi. This medium is becoming a preferred method as the use of antibiotics for suppressing bacteria results in a better recovery of fungal cells, which are sensitive to an acid environment.
Key features
Applications
Selective isolation of dermatophytes and pathogenic fungi.
Industry
Food.
Preparation
72 g in one liter of distilled water; boil for one minute, sterilize in autoclave at 118 °C for 15 minutes.
Principles and uses
Yeast Extract Soy Agar is a modification of Sabouraud Medium and was formulated by Carmichael and Claus for the selective isolation of Trichophyton verrucosum as well as other fungi associated with contagious diseases. It contains streptomycin and chloramphenicol, antibiotics that inhibit bacterial growth but allow for the detection of pathogenic fungi.
Soy peptone provides nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group. Dextrose is the fermentable carbohydrate providing carbon and energy. Bacteriological agar is the solidifying agent.
Technical specifications
| Solubility | Without residues |
|---|---|
| Appearance | Fine powder |
| Color of the dehydrated medium | Beige |
| Color of the prepared medium | Amber, slightly opalescent |
| Final pH (25 °C) | 6.6 ± 0.2 |
| Amount per litre | 72 g |
| Storage | 2 to 25 °C |
Formula
| Ingredient | g/L |
|---|---|
| Bacteriological agar | 17 |
| Chloramphenicol | 0.05 |
| Dextrose | 40 |
| Soy peptone | 10 |
| Yeast extract | 5 |
| Streptomycin | 0.03 |
Typical formula in g/L, adjusted and/or supplemented as required to meet performance criteria.
Preparation and use
Preparation
Suspend 72 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. Sterilize in autoclave at 118 °C for 15 minutes. Cool to 45-50 °C, mix well and dispense into plates.
Instructions for use
Inoculate plates with sample and incubate at 25-30 °C for up to 2-5 days.
Quality control
Microbiological test
Incubation conditions: 25-30 °C / 2-5 days.
| Microorganism | Specification |
|---|---|
| Candida albicansATCC 10231 | Good growth |
| Trichophyton mentagrophytesATCC 24957 | Good growth |
| Escherichia coliATCC 25922 | Inhibited growth |
Bibliography
- Cooke, W.B., and A. R. Brazis. 1968. Occurrence of molds and yeasts in dairy products. Mycopathol. Mycol. Appl. 35: 281-289.
- International Dairy Federation. Standard Methods ISO/DIS 6611.
- Beuchat, L.R. 1979. Comparison of acidified and antibiotic-supplemented potato dextrose agar from three manufacturers for its capacity to recover fungi from foods. J. Food Prot. 42: 427-428.
What you receive
The product
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