Dehydrated culture media
Lactose Peptone Broth DEV
For the enrichment and detection of coliforms in water according to German standard methods.
- Cat. No.
- LC-1420
- Category
- Dehydrated culture media
- Format
- 500 g
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
- Standards
- DEV
Lactose Peptone Broth DEV is used for the enrichment and the determination of the titre of coliform bacteria in the bacteriological analysis of water according to the German Standard Methods for the examination of water and the German drinking water regulations (1990).
Key features
Applications
Detection and selective enrichment of coliforms.
Industry
Water.
Standards
DEV.
Preparation
35 g in one liter of distilled water; boil for one minute, sterilize in autoclave at 121 °C for 15 minutes.
Principles and uses
Meat peptone and soy peptone provide nitrogen, vitamins, minerals and amino acids essential for growth. Lactose is the fermentable carbohydrate providing carbon and energy. Sodium chloride supplies essential electrolytes for transport and osmotic balance. Bromocresol purple is the pH indicator.
All coliforms ferment lactose with acid and gas production. This group includes the genera Escherichia, Enterobacter, Citrobacter, and Klebsiella. When lactose is fermented it produces acid that changes the color of the medium from blue-purple (alkaline) to yellow (acid).
Technical specifications
| Solubility | Without residues |
|---|---|
| Appearance | Fine powder |
| Color of the dehydrated medium | Beige |
| Color of the prepared medium | Purple |
| Final pH (25 °C) | 7.2 ± 0.2 |
| Amount per litre | 35 g |
| Storage | 2 to 25 °C |
Formula
| Ingredient | g/L |
|---|---|
| Bromocresol purple | 0.02 |
| Lactose | 10 |
| Meat peptone | 17 |
| Sodium chloride | 5 |
| Soy peptone | 3 |
Preparation and use
Preparation
Suspend 35 grams of the medium in one liter of distilled water (or 70.0 grams if a double concentration is desired). Mix well and dissolve by heating with frequent agitation. Boil for one minute until complete dissolution. Dispense into tubes with Durham gas collecting tubes for gas detection and sterilize in autoclave at 121 °C for 15 minutes.
Instructions for use
According to the German Methods, the inoculated broth is incubated for 44 ± 4 hours at 35 °C. If lactose-positive microorganisms grow, the broth colour changes to yellow.
Quality control
Microbiological test
Incubation conditions: 35 °C / 44 ± 4 h.
| Microorganism | Specification | Characteristic reaction |
|---|---|---|
| Klebsiella pneumoniaeATCC 13883 | Good growth | Medium color: yellow, gas production (+) |
| Salmonella typhimuriumATCC 14028 | Good growth | Medium color: blue, gas production (-) |
| Escherichia coliATCC 25922 | Good growth | Medium color: yellow, gas production (+) |
| Enterococcus faecalisATCC 29212 | Good growth | Medium color: greenish, gas production (+) |
| Aeromonas hydrophilaATCC 7966 | Good growth | Medium color: blue, gas production (-) |
Bibliography
- Deutsche Einheitsverfahren zur Wasser-, Abwasser- und Schlammuntersuchung. - VCH Verlagsgesellschaft, D-6940 Weinheim.
- Verordnung über Trinkwasser und über Wasser für Lebensmittelbetriebe vom 12. Dezember 1990. - Bundesgesetzbl., Teil I; 2613-2629 (1990).
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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