Coliforms and E. coli · Selective enrichment · granulated
MacConkey Broth – granulated selective lactose broth
The granulated MacConkey Broth is a selective lactose broth for the enrichment of E. coli and coliforms, including microbial limit tests of non-sterile pharmaceutical products. Granules mean less dust and easier weighing.
- Granulated format
- Bile salts select Gram-negative bacteria
- Subculture on MacConkey Agar
How MacConkey Broth works
Bile salts suppress Gram-positive bacteria, peptone and lactose support coliforms. Turbid broths after incubation are subcultured on MacConkey Agar for isolation and identification of E. coli.
Typical reactions
| Organism | Reaction |
| E. coli | Turbid growth |
| Staphylococcus aureus | No growth |
Technical data
| Preparation | 35 g/L; boil with stirring until dissolved; dispense; autoclave 121°C 15 min |
| Final pH | 7.3±0.2 |
| Incubation | 42-44°C for 24 h (growth); 48 h (selectivity) |
| Storage | Dry, dark place; keep the container tightly closed |
| Shelf life | 3 years unopened |
Applications and practical notes
In the multiple-tube (MPN) method for coliforms and E. coli, as described in FDA BAM Chapter 4 and ISO 4831, a presumptive broth is followed by confirmation broths. Typical applications include:
- Coliform and E. coli MPN counts in food and feed
- Testing of water, ice and beverages
- Hygiene monitoring in dairy, meat and ready-to-eat production
- Verification of media and methods with reference strains
Working with MacConkey Broth: Keep the bottle closed and dry; the granules keep their flow properties only when protected from humidity.
Good practice with dehydrated media: keep the bottle tightly closed in a cool, dry place, weigh the powder quickly to avoid moisture uptake, and use fresh distilled or deionised water. Check the pH of each new batch after preparation and before use, and label prepared media with the date. Performance of each lot can be verified with reference strains according to ISO 11133, the standard for the preparation, production, storage and performance testing of culture media.
About the Salmonella culture method: the reference method for Salmonella in the food chain, ISO 6579-1, has four steps: non-selective pre-enrichment, selective enrichment in two broths, plating on two selective agars and confirmation of typical colonies. The FDA BAM Chapter 5 follows the same principle with media adapted to different food types. Rapid tests and identification kits shorten the time to result, but positive screening results are usually confirmed by the culture method. COLO.Science offers products for every step, so that one supplier covers the whole procedure.
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.
MacConkey Broth is supplied by COLO.Science in the pack sizes listed under Ordering information. For larger quantities, regular deliveries or method-specific sets that include MacConkey Broth, please send us a request. With every delivery of MacConkey Broth you receive the lot number and expiry date, and on request we send the available documentation for MacConkey Broth.
Where MacConkey Broth 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 |
|---|---|---|
| MacConkey Broth, granulated | PRO7605 | 250 g |
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
COLO LabExperts
Polje ob Sotli 4, SI-3255, Slovenia
Quotations and technical support for culture media and microbiology products across our international sales territory. B2B prices are net, excluding VAT.
COLO.SCIENCE | MICROBIOLOGY SUPPORT
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.
