Ready-to-use media
MacConkey Broth EP/USP
Liquid medium, for the detection and enumeration of coliforms, according to the Pharmacopeial Harmonised Method.
- Cat. No.
- LC-4047
- Category
- Ready-to-use media
- Formats
- 2 formats
- ISO 17025 quality control
- Yes
- Storage
- 8 to 25 °C
- Standards
- European PharmacopoeiaUSP
- Also available
- Dehydrated medium, 1 format (LC-1210)
MacConkey medium is a well-known, popular enrichment medium for coliform bacteria. This MacConkey Broth is a modification of the classic medium, where neutral red is replaced by a less aggressive indicator (bromocresol purple), according to the European Pharmacopoeia.
Key features
Applications
Detection of coliforms and selective enrichment of Escherichia coli.
Industry
Clinical, dairy products, final product quality control, pharmaceutical/veterinary, water.
Standards
European Pharmacopoeia, USP.
Testing
Microbiological control according to USP and European Pharmacopoeia.
Description and technique
Description
At the beginning of the last century, MacConkey made the original formulation and included ox bile as an inhibitor of Gram-positive bacteria and litmus as the indicator of acid production from lactose sugar. More recently the litmus has been substituted by a neutral red indicator, making interpretations easier and more precise.
Advancements in the knowledge of bacterial physiology have allowed adaptation of this medium, facilitating coliform detection.
Technique
MacConkey Broth is used for the enumeration of coliforms by the MPN technique, selecting the positive tubes that show turbidity, a colour change to yellow and gas production. Confirmation of the presence of coliforms should be at 42-44 °C. The turning of the medium to yellow in the presence of E. coli may be delayed 24 h to 48 h depending on the volume and concentration of inoculum.
Each laboratory must evaluate the results according to their specifications.
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
| Code | Presentation | Filling | Packaging |
|---|---|---|---|
| LC-4047 | 20 tubes, 16 x 113 mm, with Durham tube | 9 ± 0.1 mL | 16 x 113 mm glass tubes, ink labelled, with Durham tube and metal non-injectable cap. 20 tubes per box. |
| LC-5146 | 10 prepared bottles, 125 mL | 100 ± 3 mL | 1 box with 10 bottles 125 mL. Injectable cap: plastic screw inner cap. The use of syringe needles with a diameter greater than 0.8 mm is not recommended. |
Composition
| Ingredient | g/L |
|---|---|
| Gelatin peptone | 20.00 |
| Lactose | 10.00 |
| Bile | 5.00 |
| Bromocresol purple | 0.01 |
LC-5146, bottles
| Ingredient | g/L |
|---|---|
| Gelatin peptone | 20.00 |
| Lactose | 10.00 |
| Ox bile, dried | 5.00 |
| Bromocresol purple | 0.01 |
Quality control
Physical/chemical control
| Color | Violet |
|---|---|
| pH | 7.3 ± 0.2 at 25 °C |
Microbiological control
Inoculate: 10-100 CFU (productivity) / 10³-10⁴ CFU (selectivity).
According to USP and European Pharmacopoeia.
Aerobiosis. Incubation at 30-35 °C. Reading at 24-48 h. E. coli 42-44 °C.
| Microorganism | Growth |
|---|---|
| Escherichia coliATCC 25922, WDCM 00013 | Good - yellow medium - gas (+) |
| Staphylococcus aureusATCC 6538, WDCM 00032 | Inhibited |
| Escherichia coliATCC 8739, WDCM 00012 | Good - yellow medium - gas (+) |
| Salmonella typhimuriumATCC 14028, WDCM 00031 | Good - violet medium - gas (-) |
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
- ATLAS, R.M., L.C. PARKS (1993) Handbook of Microbiological Media. CRC Press, Inc. London.
- EUROPEAN PHARMACOPOEIA 10.0 (2020) 10th ed. § 2.6.13. Microbiological examination of non-sterile products: Test for specified microorganisms. Harmonised Method. EDQM. Council of Europe. Strasbourg.
- MacCONKEY, A.T. (1905) Lactose-Fermenting Bacteria in Faeces. J. Hyg 5:333.
- MacCONKEY, A.T. (1905) Lactose-fermenting bacteria in faeces. J. Hyg 5:333.
- USP 33 - NF 28 (2011) <62> Microbiological examination of non-sterile products: Test for specified microorganisms. Harmonised Method. USP Corp. Inc. Rockville. MD. USA.
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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