Ready-to-use media
Lysine Decarboxylase Broth ISO
Liquid medium to differentiate enteric bacteria using L-lysine decarboxylation assays according to ISO and IDF standards.
- Cat. No.
- LC-4229
- Category
- Ready-to-use media
- Format
- 20 tubes
- Storage
- 8 to 25 °C
- Minimum guaranteed shelf life
- 3 months
- Minimum order
- 5 packs
- Standards
- ISO 21567ISO 22964ISO 6579
- Also available
- Dehydrated medium, 1 format (LC-1208)
The capacity to decarboxylate some amino acids has been widely employed in the classification of Enterobacteriaceae.
Key features
Applications
Differentiation of enterobacteria.
Industry
Food, water.
Standards
ISO 21567, ISO 22964, ISO 6579.
Presentation
20 tubes, 16 x 113 mm, with 7 ± 0.2 mL.
Description and technique
Description
Taylor's formulation, including lysine, has been recently included in several standards for the identification of Salmonella. This modification shows an improved performance, in comparison to Falkow's formulation.
Technique
It is advisable to use a vaseline seal to avoid spontaneous oxidation. The use of glucose in anaerobic conditions produces an acidification of the medium, causing the indicator to turn yellow.
If the organism can decarboxylate the amino acid, alkaline byproducts will be formed, turning the medium grey and finally violet. The observations of these biochemical tests are performed after an incubation period of 24 hours at 37 °C.
Presentation
| Presentation | 20 tubes, 16 x 113 mm |
|---|---|
| Filling | 7 ± 0.2 mL |
| Packaging | 16 x 113 mm glass tubes, ink labelled, metal non-injectable cap. 20 tubes per box. |
Composition
| Ingredient | g/L |
|---|---|
| Yeast extract | 3.000 |
| Dextrose | 1.000 |
| Bromocresol purple | 0.015 |
| L-Lysine | 5.000 |
Quality control
Physical/chemical control
| Color | Violet |
|---|---|
| pH | 6.1 ± 0.2 at 25 °C |
Microbiological control
Inoculum 100-1000 CFU.
Aerobiosis. Incubation at 37 ± 1 °C, reading after 24-48 ± 2 h.
| Microorganism | Growth |
|---|---|
| Proteus mirabilisATCC 12453 | Good - yellow |
| Salmonella typhimuriumATCC 14028, WDCM 00031 | Good - violet |
| Escherichia coliATCC 25922, WDCM 00013 | Good - variable reaction |
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
- DOWNES, F.P. & K. ITO (2001) Compendium of methods for the microbiological examination of foods. APHA. Washington.
- FIL-IDF Standard 93 (2001) Detection of Salmonella spp.
- ISO Standard 6579-1 (2017) Microbiology of food chain - Horizontal method for the detection, enumeration and serotyping of Salmonella - Part 1: Detection of Salmonella spp.
- ISO 21567 Standard (2004) Food and feeding stuffs - Horizontal method for the detection of Shigella spp.
- ISO 22964 (2017) Microbiology of the food chain - Horizontal method for the detection of Cronobacter spp.
- TAYLOR, W. I. (1961) Isolation of Salmonellae from Food Supplies. V. Determination of the Method of Choice for Enumeration of Salmonella. Appl. Microbiol. 9:487-490.
What you receive
The product
Shipped under controlled temperature when the product requires it.
Lot certificate
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Tracked shipment
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Frequently asked questions
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