Alkaline Saline Peptone Water (ASPW)

Alkaline Saline Peptone Water (ASPW)

High-Salinity Enrichment Broth for Halophilic Vibrio Species

Catalog Number: AS-1106

Overview

Alkaline Saline Peptone Water (ASPW) is a highly selective enrichment broth formulated for the isolation and recovery of halophilic Vibrio species, particularly Vibrio parahaemolyticus, from seafood, marine environments, and clinical specimens.

The combination of alkaline pH (8.4–8.6) and elevated salinity (2–3% NaCl) provides optimal growth conditions for marine pathogenic vibrios, while strongly inhibiting terrestrial, enteric, and non-halophilic bacteria. ASPW is recommended as a primary enrichment medium in the FDA Bacteriological Analytical Manual (BAM) and ISO 21872-1 for detection of V. parahaemolyticus.

Key Features & Benefits

• High alkalinity and salinity provide excellent selectivity for marine vibrios

• Enhanced recovery of V. parahaemolyticus compared to standard APW

• Rapid enrichment with visible turbidity within 6–18 hours

• Simple, robust formulation validated in international methods

• Essential enrichment step prior to selective plating

Typical Applications

Food & Seafood Microbiology

• Primary enrichment of Vibrio parahaemolyticus from:

  • Shrimp

  • Oysters

  • Crabs

  • Fish and shellfish

Environmental & Marine Microbiology

• Isolation of halophilic vibrios (V. vulnificus, V. alginolyticus, V. mimicus)

• Monitoring of coastal and estuarine waters

Public Health & Surveillance

• Food-safety monitoring of seafood-borne vibriosis

• Outbreak investigations and regulatory testing

Principle of the Medium

Halophilic Vibrio species exhibit rapid growth in alkaline, high-salt environments. ASPW exploits this physiological preference by combining peptone nutrients, elevated NaCl, and alkaline pH, suppressing competing intestinal flora while selectively enriching pathogenic marine vibrios prior to selective plating.

Composition (per litre)

• Peptone (bacteriological or tryptone) – 20.0 g

• Sodium Chloride (NaCl) – 20.0 g
  (Validated protocols may use 20–30 g NaCl depending on target species)

Final pH: 8.5 ± 0.2 at 25 °C

Preparation

1. Dissolve 40 g of dehydrated medium in approximately 950 mL purified water

2. Adjust volume to 1 L and mix thoroughly

3. Heat gently if required to ensure complete dissolution

4. Adjust pH to 8.5 with 1 N NaOH if necessary

5. Dispense into tubes or bottles (commonly 10 mL per tube)

6. Sterilise by autoclaving at 121 °C for 15 minutes

7. Cool to room temperature before use

Incubation

• 35–37 °C for 6–18 hours (overnight enrichment)

• Turbidity is often visible within 6–8 hours in contaminated samples

Storage & Shelf Life

• Prepared ASPW:

  • Store at room temperature, protected from light, for up to 3 months, or

  • Store at 2–8 °C for extended shelf life

• Do not use if pH drops below 8.2

Intended Use

For laboratory and research use only.
Not for diagnostic use without appropriate validation.
Not for food, therapeutic, or veterinary applications.

Quality & Documentation

• Manufactured under controlled conditions for batch consistency

• Certificate of Analysis (COA) available

• Safety Data Sheet (SDS) available upon request

Customs & Trade Information

HS / AHECC Code: 3821.00.00
Prepared culture media for development or maintenance of microorganisms