Salmonella detection · Step 2 – selective enrichment
Selenite Cystine Broth – selective enrichment broth for Salmonella
Selenite Cystine Broth is a selective enrichment broth for Salmonella from food, feed and pharmaceutical samples. It is used as one of the two parallel enrichment broths of the culture method and is prepared without autoclaving.
- Selective enrichment step of the Salmonella method
- Used in ISO, USA FDA and USP methods
- Dehydrated powder, 500 g bottle · COLO code PRO7436
How Selenite Cystine Broth works
Sodium selenite inhibits coliforms and enterococci during the first hours of incubation, while Salmonella continues to multiply. L-cystine reduces the toxicity of selenite for Salmonella and improves its recovery, and the phosphate buffer keeps the pH in the range needed for selectivity.
Technical data
| Preparation | 23 g per litre of water; heat to dissolve, do not autoclave; use on the day of preparation |
| Final pH | 7.0 ± 0.2 |
| Incubation | 35–37 °C, 24 h |
| Storage | 2–8 °C, dry and dark place; close the cap tightly after use |
| Shelf life | 3 years unopened |
Applications and practical notes
Selenite Cystine Broth is used for the selective enrichment of Salmonella in the FDA BAM Chapter 5 procedures and in pharmacopoeial testing. Typical applications include:
- foods with low background flora, such as dried and processed foods
- eggs and egg products
- dairy products
- non-sterile pharmaceutical products
Working with Selenite Cystine Broth: Do not autoclave the medium and avoid overheating, which can produce a red precipitate of selenium. The broth should be prepared and used on the same day. Sodium selenite is toxic, so the powder should be handled with gloves.
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.
Selenite Cystine 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 Selenite Cystine Broth, please send us a request.
Where Selenite Cystine Broth fits in the Salmonella workflow
- Pre-enrichment – Buffered Peptone Water or Lactose Broth
- Selective enrichment – RV or RVS Broth and Selenite Cystine or tetrathionate 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 |
|---|---|---|
| Selenite Cystine Broth, dehydrated | PRO7436 | 500 g |
| Selenite Enrichment Medium, dehydrated | PRO7568 | 500 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
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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.
