Liofilchem® Buffered Peptone Water

Buffered Peptone Water (BPW) is a non-selective pre-enrichment medium used in microbiological examination of food and related samples. It is specifically designed to improve the recovery of injured Salmonella spp. and facilitate the detection and enumeration of Enterobacteriaceae in compliance with international standards such as ISO 6579, ISO 11290, and ISO 21528. Additionally, it serves as a diluent in microbiological analyses following ISO 6887 guidelines.

Key Features

1. Pre-Enrichment Medium:
   • Promotes recovery of injured Salmonella spp. from food and environmental samples prior to selective enrichment.
2. Diluent Functionality:
   • Meets ISO standards (ISO 6887 and ISO 11290) for preparing dilutions and initial suspensions for enumeration.
3. Broad Applications:
   • Used for detecting and enumerating Enterobacteriaceae and other organisms in food products.
4. ISO Compliance:
   • Recommended by ISO 6579, ISO 21528, and ISO 11290 for food microbiology and environmental testing.
5. Reliable Buffer System:
   • Phosphates in the medium provide effective buffering capacity, maintaining pH stability for optimal microbial recovery.

Applications

1. Food Microbiology:
   • Pre-enrichment of Salmonella spp. for detection.
   • Detection and enumeration of Enterobacteriaceae in compliance with ISO 21528.
2. Environmental Monitoring:
   • Analysis of environmental samples for Salmonella spp. and hygiene indicator organisms.
3. Diluent:
   • Serves as a diluent for microbiological tests requiring sample suspensions.

Composition (Typical Formula)

Preparation Instructions

For Dehydrated Medium:

1. Suspend 20.0 g of the powder in 1 L of distilled or deionized water.
2. Heat to boiling with frequent agitation until completely dissolved.
3. Sterilize in an autoclave at 121°C for 15 minutes.

Test Procedure

1. Pre-Enrichment:
   • Add sample to BPW at a ratio of 1:10 or 1:9, depending on the method.
   • Incubate at 37 ± 1°C for 16–20 hours.
2. Diluent:
   • Prepare serial dilutions of the sample as needed.

Interpreting Results

• Turbidity: Indicates microbial growth.
• Subsequent Testing: Transfer enriched samples to selective enrichment media (e.g., Rappaport-Vassiliadis or Muller-Kauffmann broth) for further analysis.

Appearance

Storage and Shelf Life

• Dehydrated Medium: Store at 10–30°C in a dry, sealed container. Shelf life: 4 years.
• Prepared Medium: Store at 10–25°C away from light. Shelf life: 2 years.

Quality Control

Applications by ISO Standards

1. ISO 6579:
   • Pre-enrichment for Salmonella spp. detection in food samples.
2. ISO 21528:
   • Detection and enumeration of Enterobacteriaceae in food and environmental samples.
3. ISO 6887:
   • Preparation of dilutions for microbiological analysis of food and water.

Advantages

• High Recovery Rate: Optimized formulation ensures the recovery of stressed or injured bacteria.
• Versatile Use: Functions as both a diluent and pre-enrichment medium.
• ISO Compliance: Meets rigorous international standards for food microbiology.

Limitations

1. Non-Selective Medium:
   • Does not inhibit the growth of non-target organisms.
2. Secondary Enrichment Required:
   • Selective enrichment is necessary to isolate specific pathogens like Salmonella spp..

Liofilchem® Buffered Peptone Water is a versatile, ISO-compliant medium essential for food microbiology and environmental monitoring. Its dual role as a diluent and pre-enrichment medium, coupled with its ability to recover stressed Salmonella spp., makes it an indispensable tool in laboratories adhering to international standards.