Overview
EN ISO 10705-2:2001 (ISO 10705-2:2000) is the CEN-adopted international standard for the detection and enumeration of somatic coliphages in water and related matrices. It defines a standardized plaque assay procedure using an appropriate Escherichia coli host strain to detect somatic bacteriophages and expresses results as plaque-forming particles (pfp/pfu) per unit volume. The method applies to all kinds of water, sediments, sludge extracts and shellfish extracts, with dilution or preconcentration where required.
Key topics and requirements
- Scope and principle: Incubation of sample with host strain in semi-solid medium, plating, incubation and counting of visible plaques (clearance zones).
- Sample types: Freshwater, seawater, wastewater, sediments, sludge extracts and shellfish extracts.
- Media, diluents and reagents: Use analytically graded chemicals or validated dehydrated media; peptone-saline diluent recommended (Annex A lists formulations).
- Apparatus and conditions: Standard microbiological equipment required (incubators, water baths, pH meter, freezers). The standard gives operational guidance (e.g., incubation conditions) and equipment needs.
- Host strains and cultures: Guidance on culturing and maintenance of host strains and calibration of viable counts.
- Procedures covered: Standard plaque-count procedure, methods for high bacterial background, low phage counts, and presence/absence tests.
- Quality assurance and reporting: Requirements for plate reading, expression of results (pfu/pfp), and test reporting.
- Safety: Laboratory biosafety practices; precautions for chloroform handling and avoiding cross-contamination (use of biohazard cabinets).
- Normative and informative annexes: Annex A (media/reagents), Annex B (description of somatic bacteriophages), Annex C (example phage culturing).
Practical applications and users
- Who uses it: Environmental and public-health laboratories, water and wastewater testing facilities, shellfish monitoring programs, research labs, and accreditation bodies implementing standardized viral indicator testing.
- Typical uses:
- Environmental surveillance and routine water quality monitoring.
- Assessing viral removal efficacy in wastewater and drinking-water treatment processes.
- Monitoring contamination in shellfish and sediment studies.
- Research into bacteriophage ecology and method validation.
- The standard includes alternative procedures to accommodate laboratories with limited resources, facilitating broader international adoption.
Related standards
- ISO 10705 series: Part 1 (F-specific RNA bacteriophages), Part 3 (concentration methods), Part 4 (bacteriophages infecting Bacteroides fragilis).
- Normative references cited: ISO 3696 (water for laboratory use), ISO 5667 series (sampling), ISO 6887 (dilutions), ISO 8199 (enumeration of micro-organisms).
Keywords: EN ISO 10705-2:2001, ISO 10705-2:2000, water quality, somatic coliphages, bacteriophages, plaque-forming units, detection and enumeration, water monitoring.