Supplements and additives
E. coli-Coliforms Supplement (BOE)
Sterile selective supplement used for E. coli/coliform isolation.
- Cat. No.
- LC-6041
- Category
- Supplements and additives
- Format
- 10 vials, each for 500 mL of medium
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
The final purpose of this supplement is to increase the selectivity of Chromogenic Coliform Agar in order to detect total coliforms and E. coli in water and food samples.
Key features
Applications
Detection of coliforms and Escherichia coli.
Industry
Food, water.
Presentation
10 freeze-dried vials with 3 ± 0.1 g.
Packaging
22 ± 0.25 x 55 ± 0.5 mm glass vials, tag labelled, white plastic cap - 10 vials per box.
Description and technique
Description
Cefsulodin and vancomycin suppress all the accompanying microbiota, especially Pseudomonas and Aeromonas spp.
Technique
Collect, dilute and prepare samples and volumes as required according to specifications, directives, official standard regulations and/or expected results.
Reconstitute the vial with the sterile diluent in aseptic conditions and add it to 500 mL of melted agar base cooled to 50 °C.
Do not overheat once supplemented.
Pour the complete medium into Petri dishes and, once solidified on a flat surface, spread the plates either by streaking or by spiral method.
Incubate the plates in aerobic atmosphere at 35 ± 2 °C for 24-48 h.
(Incubation at 44 ± 0.5 °C increases the selectivity of the medium and the specificity for E. coli isolation.)
After incubation, count all the colonies that have appeared on the surface of the agar, observing colour development when using a chromogenic base:
E. coli produces dark blue to violet colonies due to the possession of two enzymes that cleave the chromogenic substances.
Coliform bacteria have only one enzyme, so they can cleave only one substrate, producing salmon/red colonies.
Total coliforms are the sum of E. coli colonies plus the salmon-red colonies.
Presumptive isolation of E. coli/coliforms must be confirmed by further microbiological and biochemical tests.
Presentation
| Presentation | 10 freeze-dried vials |
|---|---|
| Filling | 3 ± 0.1 g |
| Packaging | 22 ± 0.25 x 55 ± 0.5 mm glass vials, tag labelled, white plastic cap - 10 vials per box. |
Composition
| Ingredient | g/vial |
|---|---|
| Cefsulodin | 0.0025 |
| Vancomycin | 0.0025 |
Reconstitute the original freeze-dried vial by adding 6 mL of sterile distilled water.
Note: each vial is sufficient to supplement 500 mL of medium base: Chromogenic Coliform Agar.
Quality control
Physical/chemical control
| Color | White-grey |
|---|
Microbiological control
Reconstitute 1 vial as indicated in Composition; shake and dissolve completely.
Add 1 vial to 500 mL of medium base. DO NOT HEAT once supplemented.
Distribute the complete medium, cooled to 50 °C, into 90 mm plates.
Incubate according to the instructions for the complete medium indicated in Composition.
Aerobiosis. Incubation at 35 ± 2 °C, reading at 24-48 hours.
| Microorganism | Growth |
|---|---|
| Escherichia coliATCC 25922, WDCM 00013 | Good |
| Salmonella typhimuriumATCC 14028, WDCM 00031 | Good |
| Enterococcus faecalisATCC 29212, WDCM 00087 | Inhibited |
| Stph. aureusATCC 25923, WDCM 00034 | Inhibited |
| Ps. aeruginosaATCC 27853 | Inhibited |
Sterility control
100 mL TSB and 100 mL Thioglycollate.
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
- ADAMS, M., R. GRUBB, S.M. HAMER & A. CLIFFORD (1990) Colorimetric enumeration of Escherichia coli based on beta-glucuronidase activity. Appl. Environ. Microbiol. 56:2021.
- ISO 7704 Standard (1985) Water Quality - Evaluation of membrane filters used for microbiological analyses.
- KILIAN, M. & P. BÜLOW (1976) Rapid Diagnostic of Enterobacteriaceae. I. Detection of bacterial glycosidases. Acta Pathol. Microbiol. Scand. Sect. B 84:245-251.
- MANAFI, M. & W. KNEIFEL (1989) A combined chromogenic-fluorogenic medium for the simultaneous detection of total coliform and E. coli in water. Zentralbl. Hyg. 189:225-234.
- MINISTERIO DE SANIDAD Y CONSUMO (2009) Orden SCO/778/2009 de 17 de marzo sobre métodos alternativos para el análisis microbiológico del agua de consumo humano. BOE. n.º 78 de 31-04-2009. Sección I, Págs. 30417-30420. Madrid.
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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How long does delivery take?
We give you the availability with the quote, within 24 hours of your request.