Ready-to-use media
EC Medium ISO
Selective medium for the detection and enumeration (MPN) of enterobacteria in water and foodstuffs according to ISO standards.
- Cat. No.
- LC-4265
- Category
- Ready-to-use media
- Format
- 20 tubes
- ISO 17025 quality control
- Yes
- Storage
- 8 to 25 °C
- Minimum guaranteed shelf life
- 4 months
- Standards
- ISO 7251
- Also available
- Dehydrated medium, 1 format (LC-1522)
EC Broth is a buffered medium containing lactose. It is part of a range of selective broths for Enterobacteriaceae. Its efficiency or selectivity is based on bile salts' inhibitory effect on other microorganisms.
Key features
Applications
Detection of coliforms and Escherichia coli, selective enumeration of Escherichia coli.
Industry
Food, water.
Standards
ISO 7251.
Presentation
20 tubes, 16 x 113 mm, with Durham tube; filling 9 ± 0.2 mL.
Description and technique
Technique
This broth may be used for routine testing of water and food, either alone or by using the Most Probable Number method of enumeration.
The type of sample will determine how precise the results are. If the incubation is at 35-37 °C for 48 hours, gas formation may be interpreted as presumptive evidence of coliform bacteria. Later confirmation will have to be done using any of the classical methods.
Should the incubation take place at 44.5 °C, gas formation could be interpreted as a confirmation of the presence of Escherichia coli. Nevertheless, it must be taken into account that the validity of this test is highly limited by technical variations. A maximum incubation time of 24 hours in a water bath with very precise temperature regulation is therefore recommended.
When using samples greater than 10 mL, the medium must be reconstituted at a concentration equivalent to that specified on the directions, taking into account the added sample volume.
It is possible that air bubbles are generated in the Durham tube during the transport. If air bubbles are present in the Durham tube prior to inoculation, the tube should be inverted until the air is released from the Durham tube. Failure to remove air bubbles prior to inoculation may result in reading the result as a false-positive reaction in gas production.
Presentation
| Presentation | 20 tubes, 16 x 113 mm, with Durham tube |
|---|---|
| Filling | 9 ± 0.2 mL |
| Packaging | 16 x 113 mm glass tubes, ink labelled, with Durham tube and metal non-injectable cap. 20 tubes per box. |
Composition
| Ingredient | g/L |
|---|---|
| Peptone from casein | 20.0 |
| Lactose | 5.0 |
| Bile salts No. 3 | 1.5 |
| Sodium chloride | 5.0 |
| Dipotassium hydrogen phosphate | 4.0 |
| Potassium dihydrogen phosphate | 1.5 |
Quality control
Physical/chemical control
| Color | Straw-coloured yellow |
|---|---|
| pH | 6.9 ± 0.2 at 25 °C |
Microbiological control
Prepare tubes - inoculate with 100 ± 20 CFU for growth promotion or 10⁴-10⁶ CFU (selectivity).
Microbiological control according to ISO 11133:2014/Amd 1:2018.
Analytical methodology according to ISO 11133:2014/Amd 1:2018; A2:2020.
Aerobiosis. Incubation at 44 ± 1 °C. Reading at 24-48 h ± 2 h.
| Microorganism | Growth |
|---|---|
| Escherichia coliATCC 25922, WDCM 00013 | Good - gas positive |
| Escherichia coliATCC 8739, WDCM 00012 | Good - gas positive |
| Ps. aeruginosaATCC 27853, WDCM 00025 | Inhibited - poor |
Sterility control
Incubation 48 h at 30-35 °C and 48 h at 20-25 °C: NO GROWTH.
Check at 7 days after incubation in same conditions.
Bibliography
- APHA-AWWA-WEF (1998) Standard Methods for the Examination of Water and Wastewater, 20th ed. APHA, Inc., Washington. DC. USA.
- ATLAS, R.M., L.C. PARKS (1993) Handbook of Microbiological Media. CRC Press, Inc. London.
- DOWNES, F.P. & K. ITO (2001) Compendium of methods for the microbiological examination of foods. 4th ed. APHA. Washington. DC. USA.
- HORWITZ, C. (2000) Official Methods of Analysis of the AOAC International. 17th ed. Gaithersburg. MD. USA.
- ISO 7251 Standard (1993) Microbiology - General Guidance for enumeration of presumptive E. coli. M.P.N. Technique.
- MARSHALL, R. (1993) Standard Methods for the Examination of Dairy Products. 16th ed. APHA. Washington. DF. USA.
- ISO 9308-2 Standard (1990) Water Quality. Detection and enumeration of coliform organisms, thermotolerant coliform organisms and presumptive E. coli - MPN method.
- ISO 11133:2014/Amd 1:2018. Microbiology of food, animal feed and water. Preparation, production, storage and performance testing of culture media.
What you receive
The product
Shipped under controlled temperature when the product requires it.
Lot certificate
Every lot comes with its certificate.
Tracked shipment
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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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