ISO 9308-1-2014 amd1-2016 PDF

Full title and description

ISO 9308-1:2014/Amd 1:2016 — Water quality — Enumeration of Escherichia coli and coliform bacteria — Part 1: Membrane filtration method for waters with low bacterial background flora — Amendment 1. This document is an amendment to ISO 9308-1:2014 and provides technical corrections, clarifications and limited updates to the membrane‑filtration enumeration procedure for E. coli and coliform bacteria when using chromogenic coliform agar (CCA).

Abstract

ISO 9308-1:2014 specifies a membrane filtration method for the detection and enumeration of Escherichia coli and coliform bacteria in waters with low background flora (for example drinking water, disinfected pool water and finished waters from treatment plants). The procedure uses membrane filtration followed by culture on chromogenic coliform agar and calculation of colony counts (CFU) in the original sample. The amendment (Amd 1:2016) supplies targeted corrections and clarifications to the 2014 text to improve repeatability and to address minor editorial/technical points.

General information

• Status: Published (International Standard; amendment published).
• Publication date: ISO 9308-1:2014 (September 2014); Amendment 1 published December 2016 (Amd 1:2016). Consolidated EN/national adoptions were published in 2017.
• Publisher: International Organization for Standardization (ISO); adopted by various national bodies as EN/ISO consolidated texts.
• ICS / categories: 07.100.20 (Microbiology of water / Water quality).
• Edition / version: ISO 9308-1 third edition (2014) with Amendment 1 (2016). Some national bodies published consolidated EN versions (2017) that include the amendment.
• Number of pages: Base standard ISO 9308-1:2014 — 10 pages; Amendment 1:2016 — 1 page. (Consolidated national/adopted texts may have different pagination.)

Scope

Specifies a membrane filtration procedure for enumeration of E. coli and coliform bacteria in waters with low bacterial background flora. The standard defines sample handling, filtration, culture medium (chromogenic coliform agar), incubation conditions, colony identification criteria, counting and calculation of results (expressed as colony forming units per volume). It also describes limitations: the method is not suitable for waters with high background flora (e.g., many surface waters or heavily turbid samples) because non‑target background colonies may obscure accurate counts. Certain ß‑glucuronidase‑negative E. coli (for example some enterohaemorrhagic strains such as E. coli O157) may not be identified as E. coli by the chromogenic reaction and will appear as coliforms.

Key topics and requirements

• Membrane filtration as the primary concentration step for enumeration.
• Use of chromogenic coliform agar (CCA) as the differential medium and description of colony colour/appearance criteria for presumptive E. coli and coliforms.
• Specified incubation temperatures and times for reliable colony development.
• Guidance on sample volumes and dilutions so that plates produce countable colonies (often <100 total colonies on CCA).
• Calculation and reporting of colony counts (CFU per 100 mL or other unit), including treatment of multiple plates and dilutions.
• Quality control measures: use of positive/negative controls, sterility checks and media performance checks.
• Limitations and warnings about sensitivity to background flora and β‑glucuronidase‑negative E. coli strains; when to choose alternative methods (e.g., MPN/liquid enrichment methods) for high‑background waters.
• Technical corrections and clarifications introduced by Amendment 1 (2016) to improve procedure precision and editorial accuracy.

Typical use and users

Used by public‑health and environmental microbiology laboratories, water utilities, regulatory agencies, contract testing laboratories and manufacturers of culture media and filtration equipment. Typical applications include routine monitoring of drinking water, verification of disinfection performance, quality control of finished water, pool water testing and compliance testing where low background flora is expected.

Related standards

Relevant associated documents include other parts of the ISO 9308 series (for example ISO 9308-2 — Most Probable Number (MPN) / liquid enrichment methods — and ISO 9308-3 — miniaturized/MPN methods for certain surface/waste waters), general microbiology standards and guidance (for example standards on sampling, method validation and laboratory quality assurance), and consolidated EN/BS/DIN adoptions that combine ISO 9308-1:2014 with Amendment 1:2016 into a single published national/European text (published by some bodies in 2017).

Keywords

Escherichia coli, coliform, membrane filtration, chromogenic coliform agar (CCA), water quality, enumeration, CFU, drinking water, amendment 2016, ISO 9308-1, microbiology of water, quality control.

FAQ

Q: What is this standard?

A: It is ISO 9308-1:2014 with Amendment 1:2016 — an international standard that specifies a membrane‑filtration enumeration method for Escherichia coli and coliform bacteria in waters with low background flora.

Q: What does it cover?

A: It covers sample handling, membrane filtration, use of chromogenic coliform agar, incubation conditions, colony interpretation, counting and calculation of results, plus associated QA checks. The amendment (2016) provides corrections and clarifications to the 2014 text.

Q: Who typically uses it?

A: Public health and environmental labs, water utilities, regulators, contract testing laboratories and manufacturers involved in water microbiology testing and media/equipment supply.

Q: Is it current or superseded?

A: ISO 9308-1:2014 with Amendment 1:2016 is the published edition and amendment. The base standard was published in September 2014 and Amendment 1 in December 2016. Several national and regional bodies published consolidated EN/national adoptions incorporating the amendment in 2017. No later ISO replacement edition was published prior to March 2, 2026; users should check with their national standards body or ISO for any updates after that date.

Q: Is it part of a series?

A: Yes — it is Part 1 of the ISO 9308 series on detection and enumeration of E. coli and coliform bacteria. Related parts include ISO 9308-2 (Most Probable Number / liquid enrichment methods) and ISO 9308-3 (miniaturized/MPN methods for surface and waste waters), together covering a range of sample types and laboratory approaches.

Q: What are the key keywords?

A: Escherichia coli, coliform, membrane filtration, chromogenic agar, CCA, CFU, enumeration, water quality, drinking water, amendment 2016, ISO 9308-1.