ISO 8199:2018

Overview

ISO 8199:2018 - "Water quality - General requirements and guidance for microbiological examinations by culture" provides consolidated, practical guidance for laboratory manipulations common to culture-based microbiological examination of water. The standard covers preparation of samples, culture media and diluents, sterilization and glassware, common culture techniques for detection and enumeration, and criteria to select appropriate methods. It is focused on bacteria, yeasts and moulds, with some applicable content for bacteriophages, viruses and parasites, and explicitly excludes non‑culture methods such as PCR.

Key topics and technical requirements

• Sample handling and preparation: guidance on sampling, transport and preparation of water and aqueous matrices (including swabs).
• Diluents and culture media: quality requirements for ingredients, preparation and performance testing (aligned with ISO 11133).
• Sterilization and decontamination: requirements for sterilizing apparatus, consumables, decontaminating used glassware and waste management.
• Enumeration (quantitative) methods: descriptions of pour plate, spread plate, membrane filtration and liquid (MPN) techniques, plus incubation conditions, counting and result calculations.
• Detection (qualitative) methods: procedures for presence/absence testing by culture.
• Data treatment and uncertainty: guidance on calculation of results, confidence intervals and special-case counting (including duplicate plates).
• Analytical quality control (AQC): internal process controls, external quality assessment and method performance characteristics.
• Annexes of practical value: criteria for technique selection (Annex A), statistical guidance for colony counts (Annex B), duplicate‑dish calculations (Annex C), and diluent composition/preparation/QC (Annex D).

Practical applications

ISO 8199 supports consistent, reproducible culture‑based microbiological testing of water for:

• Drinking water compliance and routine monitoring
• Environmental and recreational water quality surveillance
• Wastewater and process water testing
• Public health investigations and outbreak response Using ISO 8199 helps laboratories standardize procedures (membrane filtration, pour/spread plates, MPN), reduce methodological variability, and meet accreditation and regulatory expectations.

Who should use this standard

• Water testing and environmental microbiology laboratories
• Public health and regulatory agencies
• Water utilities and industrial laboratories
• Laboratory quality managers and method developers

Related standards

• ISO 11133 - culture media preparation and QC
• ISO 19458 - sampling for microbiological analysis
• ISO 7704 - evaluation of membrane filters

Keywords: ISO 8199:2018, water quality, microbiological examinations by culture, membrane filtration, pour plate, spread plate, MPN, culture media, diluents, analytical quality control.