Salmonella detection · Step 1 – pre-enrichment
Buffered Peptone Water – non-selective pre-enrichment broth
Buffered Peptone Water (BPW) is a non-selective pre-enrichment broth for food, feed and environmental samples. It resuscitates sub-lethally injured Salmonella and Cronobacter cells before they are transferred to selective enrichment, and is also used as a diluent for the initial suspension of samples.
- First step of the Salmonella and Cronobacter culture methods
- Used in ISO and USA FDA methods
- Dehydrated powder, 500 g bottle · COLO code PRO7434
How Buffered Peptone Water works
Peptone supplies nutrients for the recovery of stressed cells without selective agents, so injured Salmonella can repair and start growing. The phosphate buffer keeps the pH stable during incubation, even in samples rich in carbohydrates whose fermentation would otherwise acidify the broth and damage the target cells.
Technical data
| Preparation | 20.1 g per litre of water; dissolve, dispense (e.g. 225 mL per flask) and sterilise at 121 °C for 15 min |
| Final pH | 7.2 ± 0.2 |
| Incubation | 36 ± 1 °C, 8–18 h |
| Storage | Dry, dark place; close the cap tightly after use |
| Shelf life | 3 years unopened |
Applications and practical notes
Buffered Peptone Water is the standard pre-enrichment broth for the detection of Salmonella according to ISO 6579-1 and is also used in the FDA BAM Chapter 5 procedures. 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 Buffered Peptone Water: The usual ratio is one part of sample to nine parts of broth, for example 25 g of sample in 225 mL of Buffered Peptone Water. After incubation, the pre-enrichment culture is transferred to RVS Broth and MKTTn Broth for selective enrichment.
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.
Buffered Peptone Water is supplied by COLO.Science in the pack sizes listed under Ordering information. For larger quantities, regular deliveries or method-specific sets that include Buffered Peptone Water, please send us a request.
Where Buffered Peptone Water 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 |
|---|---|---|
| Buffered Peptone Water, dehydrated | PRO7434 | 500 g |
| Buffered Peptone Water, granulated | PRO7620 | 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
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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.
