Dehydrated culture media
SIM Medium
For the identification and differentiation of Enterobacteriaceae and the confirmation of C. perfringens.
- Cat. No.
- LC-1514
- Category
- Dehydrated culture media
- Format
- 500 g
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
- Standards
- ISO 15213
SIM Medium is a semisolid medium used for the differentiation of enteric bacteria through sulfide production, indole formation and motility. The sulfur reduction test is useful in differentiating enteric organisms, especially Salmonella and Shigella. The indole test is used for differentiating the Enterobacteriaceae. The motility test is useful for testing a wide variety of organisms. The medium is also useful in the differentiation of Klebsiella from Enterobacter and Serratia species.
Supplement to be added: Kovac's Reagent LC-5205
Key features
Applications
Differentiation of enterobacteria.
Industry
Food, water.
Standards
ISO 15213.
Preparation
29.9 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
Casein and meat peptones provide nitrogen, vitamins, minerals and amino acids essential for growth. Casein peptone is rich in tryptophan which is reduced and produces indole. Sodium thiosulfate provides sulphur and ferric ammonium citrate is the indicator for H₂S production under alkaline conditions. Bacteriological agar is the solidifying agent in a low concentration to enable the motility to be seen.
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) | 7.3 ± 0.2 |
| Amount per litre | 29.9 g |
| Storage | 2 to 25 °C |
Formula
| Ingredient | g/L |
|---|---|
| Bacteriological agar | 3.5 |
| Meat peptone | 6 |
| Sodium thiosulfate | 0.2 |
| Ferric ammonium sulfate | 0.2 |
| Enzymatic digest of soya | 20 |
Typical formula in g/L, adjusted and/or supplemented as required to meet performance criteria.
Preparation and use
Preparation
Suspend 29.9 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.
Instructions for use
- Inoculate the pure culture by stabbing to a depth of 3/4 of the tube.
- Incubate at 37 ± 1 °C for 18-24 hours and read the results.
- Darkening indicates the production of H₂S. Motility is indicated by a diffuse turbidity away from the line of inoculation. Growth only along the inoculation line indicates non-motility.
- The presence of indole is tested by adding Kovac's Reagent (LC-5205), giving a purple-red coloration to the reagent.
Quality control
Microbiological test
Incubation conditions: 37 ± 1 °C / 18-24 h.
| Microorganism | Specification | Characteristic reaction |
|---|---|---|
| Shigella flexneriATCC 12022 | Good growth | H₂S (-), indole (-), motility (-) |
| Clostridium perfringensATCC 13124 | Good growth | H₂S (+), indole (-), motility (-) |
| Salmonella typhimuriumATCC 14028 | Good growth | H₂S (+), indole (-), motility (+) |
| Escherichia coliATCC 25922 | Good growth | H₂S (-), indole (+), motility (+) |
Bibliography
- S.A.B. Manual of Microbiological. McGraw-Hill Book Co. New York, 1957.
- Greene, Bilum de Cora, Fairchail, Kaplan, Landau and Sharp. J. Bact. 63:347. 1951.
- Harrigan W.F. and MacCarice M.E. (1966) Laboratory Methods in Microbiology. Academic Press, 53.
What you receive
The product
Shipped under controlled temperature when the product requires it.
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