Buffered Peptone Water H
Also known as：BPW · BPW H · Buffered Peptone Water · Buffered Peptone Water (Halal) · Peptone Water Buffered
For the non-selective pre-enrichment of Salmonella and other bacteria from food, animal feed, and environmental samples, and for use as a diluent.
- Category
- Dehydrated Culture Media
- Dissolve per litre
- 20 g
- pH (25 °C)
- 7.0 ± 0.5
- Appearance
- Beige powder
- Pack sizes
- 500 g · 5 kg · 25 kg
- Certifications
- ISO 22000 · Halal
- Standard methods
- ISO 6579-1·ISO 22964·FDA BAM
Data updated：2026-11-07
Brand cross-reference：BD Difco Buffered Peptone Water · Oxoid Buffered Peptone Water · Merck Buffered Peptone Water（ISO 6579-1、ISO 22964、FDA BAM） Brand cross-reference
- Shelf life
- Stored in sealed containers at 10-30°C in dry and clean conditions. Shelf life is 3 years from date of manufacture.
- Allergens
- Soy
Overview
Buffered Peptone Water (BPW) is the pre-enrichment medium specified by standard methods for Salmonella in food: both ISO 6579-1 and the FDA BAM start with it, so cells injured by heating, freezing, drying or acid can recover and multiply without selective pressure before selective enrichment. Peptone supplies nitrogen and amino acids, sodium chloride maintains osmotic balance, and the phosphate buffer holds the pH near 7.0 so the culture does not acidify and inhibit itself. This is the Halal-certified version, made from food-grade raw materials, with a COA and growth-performance test against reference strains for every batch, for food plants, testing laboratories and contract labs following standard methods.
Principle
Buffered Peptone Water was introduced by Edel and Kampelmacher as a pre-enrichment medium to improve the recovery of sub-lethally injured Salmonella from processed foods.¹ Peptone supplies nitrogen, amino acids, and peptides, and sodium chloride maintains the osmotic equilibrium. The phosphate buffer system holds the pH near neutral during incubation, preventing the fall in pH caused by the fermentation of carbohydrates present in many foods, which would otherwise injure stressed cells. The absence of selective agents allows damaged organisms to resuscitate before transfer to selective enrichment media. The medium is specified for the pre-enrichment of Salmonella and is also used for the preparation of initial suspensions and dilutions of samples.²
Choosing between Buffered Peptone Water, Peptone Water and Lactose Broth
All three are liquid media without selective agents; they differ in purpose. Buffered Peptone Water is phosphate-buffered and is the pre-enrichment medium specified by ISO 6579-1 and the FDA BAM for Salmonella, and by standard methods for Cronobacter and others. Peptone Water has no buffer and is used to dilute samples and for indole and sugar fermentation tests. Lactose Broth contains lactose and is the pre-enrichment broth in older FDA BAM editions and some dairy methods. Follow the method you are accredited to; when none is specified, use Buffered Peptone Water for Salmonella.
Specifications
| Parameter | Specification |
|---|---|
| Appearance | Beige powder |
| pH (at 25°C) | 7.0 ± 0.5 |
Release specifications. Actual values are reported on the COA supplied with each batch.
Directions
Suspend 20 g of powder in 1 L of purified water. Heat with continuous stirring and bring to the boil for 1 minute. Dispense into suitable containers. Sterilize by autoclaving at 121°C for 15 minutes. Test the finished medium for performance using stable, standard control cultures.
Cultural response
| Test organism | ATCC | Growth |
|---|---|---|
| Salmonella enterica ser. Typhimurium | 14028 | good-luxuriant |
| Salmonella enterica ser. Enteritidis | 13076 | good-luxuriant |
| Escherichia coli | 25922 | good-luxuriant |
Product highlights
- Food-grade raw materials, produced in an ISO 22000 certified facility
- Halal certified, suitable for the Malaysian, Indonesian, and Middle Eastern markets
- Manufactured to the standard formulation, 20 g per litre, pH 7.0 ± 0.5
- Performance verified against standard control strains before release (Salmonella enterica ser. Typhimurium, Salmonella enterica ser. Enteritidis, Escherichia coli)
- Available in 500 g / 5 kg / 25 kg, from laboratory to industrial scale
- COA, specification sheet, and technical data sheet available; samples on request
- Manufactured in Taiwan with reliable supply
Food grade versus laboratory grade
Most culture media suppliers use laboratory-grade raw materials, which are held to lower standards for heavy metal residues, microbial contamination control, and traceability. That is adequate for pure research but not for applications with stricter raw-material requirements. STBIO manufactures with food-grade raw materials throughout, in a facility certified to ISO 22000 food safety management.
- Food microbiology laboratories working to ISO 17025 or equivalent requirements
- Biotech manufacturers exporting fermentation products and needing full raw-material traceability
- Organisations with ESG or compliance audit requirements across their supply chain
- Companies sourcing both Halal and non-Halal products who need one consistent material grade
FDA BAM methods
This product corresponds to a medium used in the chapters of the US FDA Bacteriological Analytical Manual (BAM), the reference methods for FDA regulatory testing. Follow the current online edition of each chapter.
- FDA BAM Chapter 5: SalmonellaBAM Chapter 5Pre-enrichmentNamed in the method as：Buffered peptone water (BPW), for specified foods
- FDA BAM Chapter 29: CronobacterBAM Chapter 29Pre-enrichmentNamed in the method as：Buffered peptone water (BPW)
BAM specifies methods and media formulations; it does not certify brands. Add supplements as the chapter requires, and verify media against reference strains under your quality system.
Frequently asked questions
01Does this medium meet FDA BAM methods?
BAM specifies methods and formulations, not brands. This product corresponds to a medium used in: FDA BAM Chapter 5: Salmonella（BAM Chapter 5）: Pre-enrichment; FDA BAM Chapter 29: Cronobacter（BAM Chapter 29）: Pre-enrichment. It is manufactured to the standard formulation and ships with a COA per batch; add supplements as the chapter requires and follow the current online edition.
02Why does Salmonella testing start with pre-enrichment in Buffered Peptone Water?
Salmonella in food is usually present in low numbers and already injured by heating, freezing, drying or acid; placed straight into a selective medium with inhibitors, the cells die and the test comes back negative. Pre-enrichment in BPW, which has no selective pressure, lets injured cells repair and multiply to detectable numbers before selective enrichment and isolation. That is why ISO 6579-1 makes it the first step.
03What sample ratio and incubation does Buffered Peptone Water use?
Under ISO 6579-1, sample and BPW are mixed 1:9, for example 25 g of sample in 225 mL of BPW, homogenised and incubated at 34 to 38 °C for 18 ± 2 hours before transfer to selective enrichment broths. Follow the edition of the method you are accredited to.
04Can Buffered Peptone Water and Peptone Water be used interchangeably?
Not recommended. The difference is the phosphate buffer: during pre-enrichment the culture produces acid, and in unbuffered Peptone Water the pH drops and hinders recovery of injured cells. Use Peptone Water for sample dilution and the indole test, and the buffered version for Salmonella pre-enrichment.
05How long can prepared Buffered Peptone Water be kept?
Sterilised BPW stored at 2 to 8 °C in the dark generally keeps for about one month; bring it to room temperature and check that it is clear before use. Keep the opened powder tightly sealed and dry, as caked powder drifts in pH and performance. Your own quality system takes precedence.
06How much powder per litre?
Use 20 g per litre of deionised water; pH after sterilisation 7.0 ± 0.5. Preparation and sterilisation conditions are given on the specification sheet.
07Which organisms is it suitable for?
Enterobacteriaceae, Gram-negative, Pathogens, Salmonella, Salmonella enterica ser. Typhimurium, Salmonella enterica ser. Enteritidis, Escherichia coli. See the cultural response table and the specification sheet.
08What are the equivalent brand products and standard methods?
Cross-reference: BD Difco Buffered Peptone Water, Oxoid Buffered Peptone Water, Merck Buffered Peptone Water. Standard methods: ISO 6579-1, ISO 22964, FDA BAM. Formulations may differ slightly between makers; refer to the specification sheet.
09Can it be used for food-grade applications?
Yes. It is made from food-grade raw materials in an ISO 22000 certified facility and is suitable for culturing starters for fermented products that are consumed directly.
10How is this product prepared?
Suspend 20 g of powder in 1 L of purified water. Heat with continuous stirring and bring to the boil for 1 minute. Dispense into suitable containers. Sterilize by autoclaving at 121°C for 15 minutes. Test the finished medium for performance using stable, standard control cultures.
11How should it be stored, and what is the shelf life?
Stored in sealed containers at 10-30°C in dry and clean conditions. Shelf life is 3 years from date of manufacture.
12How do I request a bulk quotation, and can you provide a COA?
Yes. This product is available in 500 g, 5 kg, 25 kg. Tell us your application and volume when requesting a quotation; we reply within one working day and can supply the COA, specification sheet, and technical data sheet.
Academic citation
Products from this range have been cited as the culture media source in a peer-reviewed study by a National Taiwan University research team:
Chan et al. (2024). Single-strain probiotics enhance growth, anti-pathogen immunity, and resistance to Nocardia seriolae in grey mullet (Mugil cephalus) via gut microbiota modulation. Animal Microbiome, 6, 67. Springer Nature.
Media attribution: Tryptone Soy Broth, MRS medium, LB broth, beef extract, peptone, yeast extract, agar (STBIO, New Taipei, Taiwan)
Read the full paperUsed in these applications
- Fill media for beverage and food pipeline cleaning verificationAfter CIP, confirm with liquid media that the line is actually clean
- Foodborne pathogen detection: Salmonella, S. aureus, VibrioComplete media sets from pre-enrichment through selective enrichment to isolation
- Semiconductor wastewater biotreatment: media and nitrogen sources for nitrifiers, TMAH degraders and sludge acclimationStandard media and industrial nitrogen sources for culturing bioaugmentation strains and starting or re-seeding biological treatment tanks
Further reading
- FDA BAM Culture Media Cross-Reference: Which Media Each BAM Chapter Uses and the STBIO EquivalentAerobic plate count, coliforms and E. coli, Salmonella, Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, Vibrio, Clostridium perfringens, yeasts and moulds and Cronobacter: the media named in each FDA Bacteriological Analytical Manual chapter, matched to Taiwan-made dehydrated media for US laboratories qualifying a second source.
- Which Culture Media Do Taiwan FDA Food Microbiology Methods Specify? Cross-Reference for 21 Announced MethodsAerobic plate count, coliforms, E. coli, Enterobacteriaceae, Salmonella, Staphylococcus aureus, Listeria monocytogenes, lactic acid bacteria, yeasts and moulds, Bacillus cereus, Vibrio parahaemolyticus, Clostridium perfringens and Cronobacter: the media named in each Taiwan FDA (TFDA) announced method, matched to Taiwan-made products.
References
- 1. Edel W. and Kampelmacher E. H., 1973. Comparative studies on the isolation of "sublethally injured" salmonellae in nine European laboratories. Bull. World Health Organ., 48:167-174.
- 2. ISO 6579-1, Microbiology of the food chain — Horizontal method for the detection, enumeration and serotyping of Salmonella — Part 1: Detection of Salmonella spp., International Organization for Standardization, Geneva.