Salmonella detection · Step 2 – selective enrichment
MKTTn Broth Base – second selective enrichment broth for Salmonella
Muller-Kauffmann Tetrathionate-Novobiocin (MKTTn) Broth is the second selective enrichment broth of the ISO Salmonella method. It is inoculated from the pre-enrichment culture in parallel with RVS Broth. The base is completed before use with iodine–iodide solution and the MKTTn supplement.
- Second selective enrichment broth, used in parallel with RVS Broth
- Used in ISO methods
- Dehydrated powder, 500 g bottle · COLO code PRO7438
How MKTTn Broth works
Tetrathionate, formed from thiosulfate and the added iodine, is reduced by Salmonella but inhibits most coliforms. Bile salts and brilliant green suppress Gram-positive and many Gram-negative accompanying bacteria, and novobiocin further inhibits Proteus. Calcium carbonate neutralises the acid produced during tetrathionate reduction.
Applications and practical notes
MKTTn Broth is the second selective enrichment broth in ISO 6579-1, used in parallel with RVS Broth. Typical applications include:
- meat, poultry, eggs and egg products
- milk, dairy products and infant formula
- feed, spices and dry foods
- environmental swabs from the food production area
Working with MKTTn Broth Base: The usual inoculum is 1 mL of pre-enrichment culture in 10 mL of complete MKTTn Broth. The complete broth should be prepared on the day of use, because the iodine–iodide solution is not stable in the medium.
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.
MKTTn Broth Base is supplied by COLO.Science in the pack sizes listed under Ordering information. For larger quantities, regular deliveries or method-specific sets that include MKTTn Broth Base, please send us a request. With every delivery of MKTTn Broth Base you receive the lot number and expiry date, and on request we send the available documentation for MKTTn Broth Base. If you are changing to MKTTn Broth Base from another supplier, we are happy to advise on the transition.
Where MKTTn Broth fits in the Salmonella workflow
- Pre-enrichment – Buffered Peptone Water or Lactose Broth
- Selective enrichment – RVS Broth and MKTTn Broth
- Selective isolation – XLD Agar plus a second selective or chromogenic agar
- Confirmation – TSI, Lysine Iron Agar, Urea Agar, latex and biochemical identification
See the complete Salmonella set in the Microbiology Catalogue →
Ordering information
| Product | COLO code | Pack |
|---|---|---|
| MKTTn Broth Base, dehydrated | PRO7438 | 500 g |
| MKTTn Broth Supplement | PRO7719 | 10 vials |
| MKTTn Broth Supplement | PRO7732 | 5 × 2 vials |
| Tetrathionate / MKTTn Broth Supplement | PRO7668 | 2 × 5 vials |
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.
