Introduction:
Buffered Peptone Water (BPW) is a World Health Organization (WHO) and International Organization for Standardization (ISO)-recommended pre-enrichment medium for the recovery of sublethally injured Salmonella and Cronobacter sakazakii (formerly Enterobacter sakazakii) from food, animal feed, and environmental samples. Unlike selective media that can further stress damaged cells, BPW’s gentle, well-buffered formulation allows injured pathogens to repair their cellular machinery before they are exposed to selective agents. This significantly increases the probability of detecting low-level contamination, which is critical for food safety and public health.
How BPW Works / BPW:
The mechanism of BPW lies in its simple but powerful composition. Peptic digest of animal tissue provides amino acids, peptides, and growth factors necessary for bacterial resuscitation. Sodium chloride maintains the osmotic balance, while the phosphate buffer system – consisting of disodium hydrogen phosphate and potassium dihydrogen phosphate – holds the pH at a stable 7.2 ± 0.2 at 25°C. This near-neutral pH is optimal for the repair of damaged Salmonella and Cronobacter cells. The absence of inhibitors or selective agents allows even severely stressed cells to grow without competition. After an incubation period of 16–20 hours at 37°C, the pathogens multiply to detectable levels and can be subcultured onto selective agars such as XLD, Rambach, or Chromogenic Cronobacter agar.
Key Benefits:
- High Recovery Rate: BPW outperforms many other pre-enrichment broths for Salmonella, especially from heat‑stressed, freeze‑damaged, or low‑moisture foods.
- Standardized Formulation: Our BPW follows ISO 6579‑1 and FDA BAM (Bacteriological Analytical Manual) specifications, ensuring reproducible results across different laboratories.
- Easy to Use: No pH adjustment required after autoclaving. Simply dissolve 20.0 g per liter, autoclave at 121°C for 15 minutes, and cool.
- Economical 250g Size: Each bottle prepares 12.5 liters of final medium – ideal for routine testing without frequent repurchasing.
- Long Shelf Life: Three years when stored in original closed container at 2‑30°C, protected from light and humidity.
Applications:
- Food Industry: Testing raw meat, poultry, seafood, dairy, powdered infant formula, spices, nuts, and processed ready‑to‑eat foods.
- Environmental Monitoring: Swabs from food contact surfaces, equipment, and production areas.
- Animal Feed: Pre‑enrichment of Salmonella in feed ingredients and finished feed.
- Pharmaceutical & Cosmetics: Screening non‑sterile raw materials for enteric pathogens.
- Clinical Samples: Although primarily for food, BPW can also be used for stool or environmental clinical samples.
- Learn more about Salmonella from the CDC Salmonella Page →
- Official ISO 6579‑1 standard overview on ISO Website →
- Cronobacter information from the FDA →
- Wikipedia entry for Buffered Peptone Water →
