Ready-to-use media
Lactose Broth (Double Concentration)
Medium for pre-enrichment and detection of enterobacteria and coliforms in milk and water according to ISO standards.
- Cat. No.
- LC-4013
- Category
- Ready-to-use media
- Format
- 20 tubes
- Storage
- 8 to 25 °C
- Minimum guaranteed shelf life
- 4 months
- Minimum order
- 20 packs
Lactose Broth is a classical medium for use in the presumptive testing for coliforms and for the enrichment of Salmonella. This formulation is per the standards recommended by APHA, AWWA, USP-NF and ISO.
Key features
Applications
Confirmation of coliforms and enrichment of Salmonella.
Industry
Food, water.
Presentation
20 tubes, 17 x 145 mm, with Durham tube inside; filling 10 ± 0.3 mL.
Packaging
17 x 145 mm glass tubes, ink labelled, metal non-injectable cap. 20 tubes per box, with Durham tube.
Description and technique
Description
It is commonly used with Durham fermentation tubes for the detection of gas formation. If a specific volume of sample is to be inoculated, this must be taken into consideration when making up the medium, as the concentration must not be altered on addition of the inoculum.
Note: in this case the medium is prepared to double concentration to add a sample volume of 10 mL.
Although it is not Eijkman's original formulation, this broth provides excellent results in assays of gas production at 44 ± 1 °C, which is a characteristic of Escherichia coli.
While preparing this medium it is important to avoid overheating and to distribute it into tubes before sterilization.
Technique
To inoculate tubes, follow the standard laboratory methods or the applicable norms (stab inoculation, loop inoculation, dilution banks, Most Probable Number (MPN) technique, pipette inoculation, etc.).
Presentation
| Presentation | 20 tubes, 17 x 145 mm, with Durham tube inside |
|---|---|
| Filling | 10 ± 0.3 mL |
| Packaging | 17 x 145 mm glass tubes, ink labelled, metal non-injectable cap. 20 tubes per box, with Durham tube. |
Composition
| Ingredient | g/L |
|---|---|
| Peptone from gelatin | 10.0 |
| Meat extract | 6.00 |
| Lactose | 10.0 |
Quality control
Physical/chemical control
| Color | Yellow |
|---|---|
| pH | 6.9 ± 0.2 at 25 °C |
Microbiological control
Inoculate: practical range 100 ± 20 CFU; min. 50 CFU (productivity).
Dilute to normal concentration.
Aerobiosis. Incubation at 35 ± 2 °C. Reading at 24 hours.
| Microorganism | Growth |
|---|---|
| Escherichia coliATCC 25922, WDCM 00013 | Good - gas positive |
| Escherichia coliATCC 8739, WDCM 00012 | Good - gas positive |
| Salmonella typhimuriumATCC 14028, WDCM 00031 | Good - gas negative |
| Enterococcus faecalisATCC 29212, WDCM 00087 | Good - gas negative |
| Citrobacter freundiiATCC 43864, WDCM 00006 | Good - gas positive |
| Ps. aeruginosaATCC 27853, WDCM 00025 | Good - gas negative |
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
- APHA-AWWA-WPCF (1998) Standard methods for the examination of water and wastewater. 20th ed. APHA Washington.
- DOWNES, F.P. & K. ITO (2001) Compendium of Methods for the Microbiological Examination of Foods. 4th ed. APHA. Washington.
- FDA (Food and Drug Administration) (1998) Bacteriological Analytical Manual 8th ed. Rev A. AOAC International. Gaithersburg. VA. USA.
- ISO 9308-2 Standard. (1990) Water Quality - Detection and enumeration of coliform organisms, thermotolerant coliform and presumptive E. coli - MPN technique.
- ISO 11133:2014/Amd 1:2018. Microbiology of food, animal feed and water. Preparation, production, storage and performance testing of culture media.
- ISO 21150:2006 Standard. Cosmetics - Detection of Escherichia coli.
- US PHARMACOPOEIA (2005) <61> Microbial limit test. US Pharmacopeial Conv. Inc. Rockville. MD. USA.
- VANDERZANT & SPLITTSTOESSER (1992) Compendium of Methods for the Microbiological Examination of Foods. 3rd ed. APHA. Washington.
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?
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