Ready-to-use media
Tryptophan Culture Broth ISO
Liquid medium used for the detection of indole production according to ISO standards.
- Cat. No.
- LC-4027
- Category
- Ready-to-use media
- Format
- 20 tubes
- Storage
- 8 to 25 °C
- Minimum guaranteed shelf life
- 4 months
- Minimum order
- 5 packs
- Standards
- ISO 16654
- Also available
- Dehydrated medium, 1 format (LC-1237)
This broth allows the indole production from the tryptophan, and therefore it is suitable for the differentiation and identification of coliforms from water and food. Its formulation is according to the German standards for waters and foods, and complies with the specifications of several ISO standards related to the presence and identification of Escherichia, Salmonella and Shigella in different products.
Key features
Applications
Detection of coliforms and confirmation of Escherichia coli.
Industry
Food.
Standards
ISO 16654.
Presentation
20 tubes, 16 x 113 mm, with 9 ± 0.1 mL.
Description and technique
Technique
The medium is inoculated with the previously isolated culture, and then incubated at 35-37 °C for 24 hours. Indole production is observed by adding a few drops of Kovac's Reagent over the broth (with or without previous extraction) and shaking gently. Formation of a red ring indicates indole presence.
Presentation
| Presentation | 20 tubes, 16 x 113 mm |
|---|---|
| Filling | 9 ± 0.1 mL |
| Packaging | 16 x 113 mm glass tubes, ink labelled, metal non-injectable cap. 20 tubes per box. |
Composition
| Ingredient | g/L |
|---|---|
| Tryptone | 10.0 |
| L-tryptophan | 1.0 |
| Sodium chloride | 5.0 |
Quality control
Physical/chemical control
| Color | Yellowish |
|---|---|
| pH | 7.2 ± 0.2 at 25 °C |
Microbiological control
Inoculate a pure culture.
Microbiological control according to ISO 11133:2014/Amd 1:2018.
Aerobiosis. Incubation at 37 ± 1 °C, reading after 24 ± 3 h.
| Microorganism | Growth |
|---|---|
| Escherichia coliATCC 25922, WDCM 00013 | Good - positive indole |
| Salmonella typhimuriumATCC 14028, WDCM 00031 | Good - negative indole |
| Escherichia coliATCC 8739, WDCM 00012 | Good - positive indole |
| Shigella sonneiATCC 9290 | Good - negative indole |
Sterility control
Incubation 48 hours at 30-35 °C and 48 hours at 20-25 °C: NO GROWTH.
Check at 7 days after incubation in same conditions.
Bibliography
- BUNDESGESMELHEITSAMT: Amtliche Samnulung von Untersuchungs Verfahren nach #35LMBG. Beuth Verlag. Berlin-Köln.
- DIN 38411-6 (1991) Deutsche Einheitsverfahren zur Wasser-, Abwasser- und Schlammuntersuchung; Mikrobiologische Verfahren (Gruppe K); Nachweis von Escherichia coli und coliformen Keimen (K6).
- ISO Standard 6785:2001. Milk and Milk Products. Detection of Salmonella spp.
- ISO Standard 9308-1:2000. Water Quality. Detection and enumeration of Escherichia coli and coliform bacteria. Part 1: Membrane filtration method.
- ISO 11133:2014/Amd 1:2018. Microbiology of food, animal feed and water. Preparation, production, storage and performance testing of culture media.
- ISO Standard 21567:2004. Microbiology of Foods and animal feeding stuffs - Horizontal method for the detection of Shigella spp.
- VERORDNUNG über Trinkwasser und über Wasser für Lebensmittelbetriebe vom 12-12-1990. Bundesgesatbl. I. 2613-2619.
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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Frequently asked questions
Can I ask for formats other than those listed?
Yes: custom formats and OEM packs are available on request. Tell us the quantities you need.
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