Coliforms and E. coli · Defined substrate test
ONPG-MUG Medium – coliforms and E. coli in one test
ONPG-MUG Medium is a minimal medium with two enzyme substrates for the simultaneous detection of coliforms and E. coli in water. One pack is added to the water sample; colour shows coliforms and fluorescence shows E. coli.
- Yellow = coliforms (ONPG)
- Blue fluorescence = E. coli (MUG)
- Pre-weighed packs
How ONPG-MUG Medium works
β-galactosidase of coliforms splits ONPG and releases yellow o-nitrophenol. β-glucuronidase of E. coli splits MUG and gives blue fluorescence under UV light at 366 nm. The minimal medium supports target bacteria but few others.
Applications and practical notes
Membrane filtration and presence-absence media are used for coliforms and E. coli in drinking water, source water and bottled water. Typical applications include:
- Drinking water and source water monitoring
- Bottled water and ice testing
- Swimming pool and process water checks
- Laboratories working with membrane filtration
Working with ONPG-MUG Medium: Compare each sample with a comparator or a negative control and read fluorescence in a darkened room.
Good practice with rapid tests: store the kit as stated on the label, let the components reach room temperature before use and use each item only once. Record the lot number and the result, and confirm positive results according to the reference method when this is required.
About coliform and E. coli methods: coliforms and E. coli are counted either by the multiple-tube (MPN) method, with a presumptive broth followed by confirmation broths, or by colony counts on selective agars. FDA BAM Chapter 4 describes both approaches for food and water, and ISO 16649-2 gives the colony-count method for β-glucuronidase-positive E. coli on TBX Agar. E. coli O157 and other STEC need dedicated media, serology and PCR. COLO.Science offers media, supplements, rapid tests, identification kits and QC strains for every step.
Complete sets from one supplier: COLO.Science supplies culture media, supplements, rapid tests, identification kits and QC strains as complete sets for the method you follow. Send us your sample types and standards, and we will prepare an offer with the matching products and documentation.
ONPG-MUG Medium is supplied by COLO.Science in the pack sizes listed under Ordering information. For larger quantities, regular deliveries or method-specific sets that include ONPG-MUG Medium, please send us a request. With every delivery of ONPG-MUG Medium you receive the lot number and expiry date, and on request we send the available documentation for ONPG-MUG Medium.
Where ONPG-MUG Medium fits in coliform and E. coli testing
- Presumptive test – Lauryl Sulfate Tryptose Broth (MPN) or VRBL / chromogenic agar (colony count)
- Confirmation – BGLB Broth for coliforms; EC or EC-MUG Broth at 44.5 °C for E. coli
- Isolation – EMB, MacConkey, TBX or chromogenic E. coli agar
- Identification – IMViC kit; for O157 and STEC: SMAC or chromogenic O157 agar, latex and PCR
Ordering information
| Product | COLO code | Pack |
|---|---|---|
| ONPG-MUG Medium for Coliforms and E. coli | PRO7823 | 100 packs |
Product notice: preparation, storage conditions and shelf life are given on the label. Technical data on this page are for orientation; the label and the lot documentation apply. B2B prices are quoted net, excluding VAT.
Sales and technical support
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Quotations and technical support for culture media and microbiology products across our international sales territory. B2B prices are net, excluding VAT.
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Need the complete set for your method?
Send the sample type, target organism and the standard you follow. COLO.Science will put together the media, supplements, QC strains and confirmation tests for the whole procedure.
