Dehydrated culture media
TSN Agar (Tryptone Sulfite Neomycin)
For the selective isolation of Clostridium perfringens from foods and other material.
- Cat. No.
- LC-1075
- Category
- Dehydrated culture media
- Format
- 500 g
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
TSN Agar (Tryptone Sulfite Neomycin) is a selective medium that can be used in tubes or plates for the identification and enumeration of Clostridium perfringens in foods and other materials, especially from mixed contaminating flora.
Key features
Applications
Selective isolation of Clostridium perfringens.
Industry
Food.
Preparation
40 g in one liter of distilled water; boil for one minute, sterilize in autoclave at 118 °C for 15 minutes, do not overheat.
Principles and uses
Casein peptone provides nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly the B-group. Ferric citrate and sodium sulfite are H₂S indicators. C. perfringens reduces the sulfite to sulfide, which reacts with the iron and forms a black iron sulfide precipitate, seen as black colonies. Bacteriological agar is the solidifying agent. Polymyxin and neomycin sulfates inhibit the growth of the majority of enterobacteria and Clostridium bifermentans. The incubation at a temperature of 46 °C allows specific and quantitative results.
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) | 7.0 ± 0.2 |
| Amount per litre | 40 g |
| Storage | 2 to 25 °C |
Formula
| Ingredient | g/L |
|---|---|
| Bacteriological agar | 13.5 |
| Casein peptone | 15 |
| Neomycin sulfate | 0.05 |
| Polymyxin B sulfate | 0.02 |
| Sodium sulfite | 1 |
| Yeast extract | 10 |
| Ferric citrate | 0.5 |
Typical formula in g/L, adjusted and/or supplemented as required to meet performance criteria.
Preparation and use
Preparation
Suspend 40 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 118 °C for 15 minutes. DO NOT OVERHEAT.
Instructions for use
Inoculate the medium with the sample and incubate at 46 ± 1 °C for 18-24 hours. Use an anaerobic jar for incubation in a H₂/CO₂ atmosphere if possible. For aerobic incubation in tubes, cover the tubes with a layer of sterile medium. Read within half an hour after taking the plates out of the jars and observe for black colonies, which can lose their color by oxidation in air after this time period.
Quality control
Microbiological test
Incubation conditions: 46 ± 1 °C / 18-24 h.
| Microorganism | Specification | Characteristic reaction |
|---|---|---|
| Clostridium perfringensATCC 12916 | Good growth | Black colony |
| Clostridium perfringensATCC 13124 | Good growth | Black colony |
| Escherichia coliATCC 25922 | Inhibited growth | |
| Pseudomonas aeruginosaATCC 27853 | Inhibited growth |
Bibliography
- Angelotti, Nall, Foter and Lewis. Applied Microbiol. 10: 193. 1962.
- Mossel. J. Sci. Agr. 10: 662. 1959.
- Mossel, de Bruin, Van Diepen, Vendrig and Zoutwelle. J. Applied Bact. 19: 142. 1956.
What you receive
The product
Shipped under controlled temperature when the product requires it.
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