prEN ISO 22118

• Abstract:

  ISO 22118:2010 specifies minimum requirements of performance characteristics for the detection of nucleic acid sequences (DNA or RNA) by molecular methods. ISO 22118:2010 applies to the detection of food-borne pathogens in foodstuffs and isolates obtained from them using molecular detection methods based on the polymerase chain reaction (PCR).; ISO 22118:2010 is also applicable, for example, to the detection of food-borne pathogens in environmental samples and in animal feeding stuffs.

• Status: Not Published
• Publication Date: 21-Feb-2028
• ICS: 07.100.30 - Food microbiology
• Technical Committee: CEN/TC 463 - Microbiology of the food chain
• Drafting Committee: CEN/TC 463/WG 1 - General requirements relating to PCR methods
• Current Stage: 4020 - Submission to enquiry - Enquiry
• Start Date: 03-Sep-2026
• Completion Date: 03-Sep-2026
• Ref Project: oSIST prEN ISO 22118:2026 - Microbiology of the food chain - Polymerase chain reaction (PCR) for the detection and quantification of microorganisms - Performance characteristics (ISO/DIS 22118:2026)

• Revises: EN ISO 22118:2011 - Microbiology of food and animal feeding stuffs - Polymerase chain reaction (PCR) for the detection and quantification of food-borne pathogens - Performance characteristics (ISO 22118:2011)
• Effective Date: 28-Aug-2024

prEN ISO 22118 is a draft European standard for microbiology of the food chain that sets performance characteristics for PCR-based assays used to detect and quantify microorganisms. It defines minimum requirements for assay specificity, dynamic range, limit of detection, limit of quantification, robustness and precision for food, feed, environmental and primary production samples.

What does prEN ISO 22118 specify?

prEN ISO 22118 specifies minimum performance characteristics for detecting and quantifying nucleic acid sequences (DNA or RNA) by PCR-based assays. It is written for assays used on microorganisms linked to human food, animal feed, environmental samples in food and feed production, and samples from primary production.

The document excludes culturing and nucleic acid extraction stages, so it covers the PCR-based assay itself rather than the full laboratory workflow. It is organized into clauses 1 to 5 plus a bibliography, with clause 3 defining the key terms and clause 4 setting the performance characteristics.

What are the key requirements of prEN ISO 22118?

prEN ISO 22118 requires the performance characteristics to be established for the assay exactly as it is intended to be used, and to be reported with the complete analytical procedure. In practice, this means the laboratory or kit provider should test the method under realistic conditions, not only under ideal conditions.

Clause 4.2 requires the purpose, intended use and limitations of the PCR-based assay to be stated. The provider also has to indicate that the criteria in this document are fulfilled, so users know what the assay is designed to do and where it should not be applied.

Clause 4.3 and 4.4 tie the work to ISO 22174. The laboratory setup, reagents, consumables and equipment need to follow that standard, and the analytical controls must be specified and recorded, including positive PCR controls, negative PCR controls, and internal or external amplification controls.

Clause 4.5 focuses on specificity. The standard expects both in silico design checks and empirical testing for inclusivity and exclusivity, with cross-reactivity documented where it appears. For the user, this is the evidence that the assay detects the intended target and does not react badly with related organisms or background nucleic acids in the sample.

Clause 4.6 requires a dynamic range for quantitative PCR-based assays to be established from purified nucleic acid of known concentration. The assay should be shown to work over the concentration range where quantification is reliable, usually with a standard curve and with the lower end close to the expected LOQ.

Clause 4.7 and 4.8 set out the limit of detection (LOD) for qualitative assays and the limit of quantification (LOQ) for quantitative assays. The LOD work shows how little target can still be detected with a stated probability, while the LOQ work shows the lowest level that can be quantified with acceptable trueness and precision.

Clause 4.9 and 4.10 address robustness and precision. The assay should be challenged with small deliberate changes such as PCR equipment, reagents, plastics, annealing temperature, master mix volume and primer or probe concentration, and precision should be checked under repeatability or intermediate precision conditions.

What terms does prEN ISO 22118 define?

• Analyte - the microorganism or related substance detected by the method; in this document, the term refers to nucleic acid sequences.
• Genome equivalent - a quantitative unit corresponding to one complete genome, used when translating target copy numbers into estimated genome counts.
• PCR-based assay - detection or quantification of nucleic acid by PCR or a variant such as reverse transcription PCR, without sample preparation, enrichment or nucleic acid extraction.
• Specificity - the ability to detect only the intended target without meaningful interference from related or other nucleic acids.
• Dynamic range - the concentration interval over which the assay has a suitable level of precision.
• Limit of detection (LOD) - the lowest analyte concentration that can be detected with a stated probability.
• Limit of quantification (LOQ) - the lowest analyte concentration that can be quantified with acceptable precision.
• Robustness - the capacity of the analytical procedure to remain stable when small method changes are introduced.

Who uses prEN ISO 22118?

prEN ISO 22118 is used by laboratories that develop, verify or run PCR-based assays for food microbiology. It is also relevant to assay suppliers, validation teams, quality managers, technical buyers, and organizations working with food, feed, environmental monitoring and primary production samples.

It helps users decide what performance evidence they need before they put a PCR assay into routine use, and what to record in method files, technical documentation and test reports.

What changed in prEN ISO 22118 from the previous edition?

prEN ISO 22118 replaces the first edition, ISO 22118:2011, and states that it has been technically revised. The document says the main changes are:

• the whole document was adapted for PCR-based assay specifications to distinguish it clearly from method validation in ISO 17468 and ISO 16140;
• the terms and definitions were updated to refer to newer documents;
• the clauses on trueness, false positives, false negatives and the outdated annex were removed;
• more guidance and examples were added for generating performance characteristics;
• the text was editorially revised.

Which standards are used with prEN ISO 22118?

Standard	Role in prEN ISO 22118
ISO 22174	Normative reference for general requirements and definitions for PCR-based methods
ISO 17468	Validation of standardized reference methods for complete analytical procedures
ISO 16140 (all parts)	Validation of food chain methods, including alternative methods against a reference method
ISO 20836	Thermal performance testing of thermal cyclers, cited for robustness and compliance testing
ISO 11781	Guidance for single-laboratory validation of qualitative real-time PCR methods, cited for LOD design
ISO/TS 12869	Statistical background, formulas and examples for LOQ determination
ISO 15216-1	Reference sequences and guidance for norovirus and hepatitis A virus inclusivity work
ISO 11133	Preparation, storage and performance testing of culture media and reference strain handling

What does the prEN ISO 22118 document contain?

Clause 4 includes the performance-characteristics framework and a table showing which characteristics apply to qualitative and quantitative PCR-based assays. It also includes practical guidance on specificity, dynamic range, LOD, LOQ, robustness and precision.

The document also contains reporting requirements in clause 5, with separate checklists for qualitative and quantitative PCR-based assays. These checklists tell the user what to document about the laboratory, instruments, sample numbers, specificity results, detection or quantification results, robustness, controls and acceptance criteria.

Clause 4 also refers to a formula for assessing LOQ and gives example test designs for robustness, including tabular factor combinations. That material is meant to support method development, verification and technical reporting rather than to reproduce a single fixed test recipe.

SLOVENSKI STANDARD
01-november-2026
Mikrobiologija v prehranski verigi - Odkrivanje in kvantifikacija mikroorganizmov
s polimerazno verižno reakcijo (PCR) - Izvedbena merila (ISO/DIS 22118:2026)
Microbiology of the food chain - Polymerase chain reaction (PCR) for the detection and
quantification of microorganisms - Performance characteristics (ISO/DIS 22118:2026)
Mikrobiologie der Lebensmittelkette - Polymerase-Kettenreaktion (PCR) zum Nachweis
und zur quantitativen Bestimmung von Mikroorganismen - Leistungsmerkmale (ISO/DIS
22118:2026)
Microbiologie de la chaîne alimentaire - Réaction de polymérisation en chaîne (PCR)
pour la détection et la quantification des micro-organismes - Caractéristiques de
performance (ISO/DIS 22118:2026)
Ta slovenski standard je istoveten z: prEN ISO 22118
ICS:
07.100.30 Mikrobiologija živil Food microbiology
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 22118
ISO/TC 34/SC 9
Microbiology of the food chain —
Secretariat: AFNOR
Polymerase chain reaction (PCR)
Voting begins on:
for the detection and quantification
2026-09-01
of microorganisms — Performance
characteristics
Voting terminates on:
ICS: 07.100.30
2026-11-24
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document has not been edited by the ISO Central Secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 22118:2026(en)
ISO/DIS 22118:2026(en)
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO/DIS 22118:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Performance characteristics for PCR-based detection and quantification assays . 3
4.1 General .3
4.2 Scope of the PCR-based assay.4
4.3 General environmental laboratory requirements .4
4.4 Analytical controls .4
4.5 Specificity .4
4.5.1 General .4
4.5.2 In silico specificity .4
4.5.3 Inclusivity test .5
4.5.4 Exclusivity test .5
4.6 Dynamic range .6
4.7 Limit of detection of qualitative PCR-based assays .7
4.8 Limit of quantification of quantitative PCR-based assays .7
4.9 Robustness .8
4.9.1 General .8
4.9.2 Robustness . . .8
4.10 Precision . . .9
5 Report of performance characteristics . 10
5.1 Qualitative PCR-based assay .10
5.2 Quantitative PCR-based assays.10
Bibliography .12

iii
ISO/DIS 22118:2026(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at www.iso.org/
patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO’s adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 9,
Microbiology, in collaboration with the European Committee for Standardization (CEN) Technical Committee
CEN/TC 463, Microbiology of the food chain, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 22118:2011), which has been technically
revised. The main changes are as follows:
— adapted the whole document for PCR-based assay specifications to have a clear distinction between this
[1] [2]
document and method validation according to ISO 17468 and ISO 16140 (all parts) ;
— updated Terms and Definitions with references to new documents;
— removed clauses about trueness, false-positives, false negatives and the outdated annex;
— added more guidance and examples for generating the performance characteristics;
— editorially revised.
iv
ISO/DIS 22118:2026(en)
Introduction
Molecular detection and quantification methods have been developed during the last few decades,
and are now available for many food associated non-pathogenic (including probiotics) and pathogenic
microorganisms.
Although until now most molecular based methods have been based on the polymerase chain reaction
(PCR) and real-time PCR, other molecular detection and quantification principles should be kept under
consideration.
To compare molecular based assays with conventional methods or with other principles, it is necessary to
generate minimum requirements for performance characteristics of the assays to be developed. Validation
[1] [2]
for the complete analytical procedures are specified in ISO 17468 and the ISO 16140 (all parts) .
This International Standard is part of a series of documents under the general title Microbiology of the food
chain — Polymerase chain reaction (PCR) for the detection and quantification of microorganisms together with:
[3]
— ISO 20836 , Microbiology of the food chain — Polymerase chain reaction (PCR) for the detection of
microorganisms — Thermal performance testing of thermal cyclers
[4]
— ISO 22174 , Microbiology of the food chain — Polymerase chain reaction (PCR) for the detection and
quantification of microorganisms — General requirements and definitions

v
DRAFT International Standard ISO/DIS 22118:2026(en)
Microbiology of the food chain — Polymerase chain reaction
(PCR) for the detection and quantification of microorganisms
— Performance characteristics
1 Scope
This document specifies minimum requirements of performance characteristics for the detection and
quantification of nucleic acid sequences (DNA or RNA) by PCR-based assays.
The PCR-based assays specified in this document do not include culturing and nucleic acid extraction stages.
[5]
NOTE ISO 22174:2024 , clause 13, states that this document specifies the performance characteristics for PCR-
based methods. To differentiate from complete methods, which are evaluated according to validation standards such
as the ISO 16140 series, the term "PCR-based assay" is used in this document.
This document applies to the detection and/or quantification of nucleic acids of microorganisms (bacteria,
yeasts, moulds, viruses and protozoan parasites) associated with:
— products intended for human consumption;
— products for feeding animals;
— environmental samples in the area of food and feed production and handling;
— samples from the primary production stage.
This document, or parts of it, is also applicable to other fields of PCR diagnostics based on a case-by-case
evaluation.
This document does not apply to sequencing methods or isothermal amplification methods like loop
mediated amplification (LAMP) or nucleic acid sequence-based amplification (NASBA).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 22174, Microbiology of the food chain — Polymerase chain reaction (PCR) for the detection and quantification
of microorganisms — General requirements and definitions
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
analyte, noun
microorganism or associated biochemicals (e.g. DNA, proteins, or lipopolysaccharides) or its products (e.g.
toxins) detected, quantified, semi-quantified, confirmed, typed or identified by the method of analysis
Note 1 to entry: In this document the term analyte refers to nucleic acid sequences.
[SOURCE: ISO/PWI 16140-1, 3.7, modified - added Note 1 to entry.]

ISO/DIS 22118:2026(en)
3.2
genome equivalent
quantitative unit used in molecular biology to express the amount of nucleic acid corresponding to one
complete genome of an organism
Note 1 to entry: Genes can be single copy or multicopy in microorganisms. This shall be taken into account when
converting measured target copy numbers to estimated genome equivalents.
3.3
PCR-based assay
detection or quantification of nucleic acid using the polymerase chain reaction (PCR) or a variant, such as
reverse transcription PCR
Note 1 to entry: The PCR-based assay does not include additional steps such as sample preparation, microbial
enrichment and nucleic acid extraction, which is necessary for a PCR-based method.
3.4
qualitative method, noun
method of analysis whose response is that the analyte is either detected or not detected, either directly or
indirectly in a specified test portion
[SOURCE: ISO/PWI 16140-1, 3.87]
3.5
quantitative method, noun
method of analysis whose response is the amount [count or mass] of the analyte measured either directly
(e.g. enumeration in a mass or a volume), or indirectly (e.g. colour absorbance, impedance, etc.) in a specified
test portion
[SOURCE: ISO/PWI 16140-1, 3.88]
3.6
specificity, noun
ability to detect only the intended target and that quantification of the target is not affected by cross-
reactivity from related or potentially interfering nucleic acids or specimen-related conditions
[6]
[SOURCE: ISO 20395:2019 , 3.33, modified — used the example specific for PCR as the definition.]
3.7
dynamic range
quantity interval within which the PCR-assay has a suitable level of precision
[7]
[SOURCE: ISO 16577:2022 , 3.3.6, modified - exchanged "analytical procedure has been demonstrated by a
collaborative trial or other appropriate validation (e.g. reference materials or dilutions) to have" with "PCR-
assay has" and removed "and accuracy".]
3.8
limit of detection
LOD , noun
PCR,x
lowest analyte concentration in a sample that can be detected with a probability of x %
EXAMPLE LOD is the limit of detection for which 50 % of tests give a positive result.
PCR,50
3.9
limit of quantification
LOQ , noun
PCR
lowest analyte concentration that can be quantified with an acceptable level of precision under the
conditions of the test
ISO/DIS 22118:2026(en)
3.10
precision, noun
closeness of agreement between independent test/measurement results obtained under stipulated
conditions
Note 1 to entry: Precision depends only on the distribution of random errors and does not relate to the true value or
the specified value.
Note 2 to entry: The measure of precision is usually expressed in terms of imprecision and computed as a standard
deviation of the test results. Less precision is reflected by a larger standard deviation.
Note 3 to entry: Quantitative measures of precision depend critically on the stipulated conditions. Repeatability and
reproducibility conditions are particular sets of extreme conditions.
[8]
[SOURCE: ISO 5725-1:2023 , 3.12]
3.11
robustness
measure of the capacity of an analytical procedure to remain unaffected by small variations in method
parameters which provides an indication of the method’s reliability during normal usage
[7]
[SOURCE: ISO 16577:2022 , 3.3.71, modified — removed the admitted term "ruggedness" and changed
"parameters and provides" to "parameters which provide".]
3.12
performance characteristics, noun
parameters that demonstrate the suitability of a PCR-based assay for the intended purpose
4 Performance characteristics for PCR-based detection and quantification assays
4.1 General
This clause contains information on how to establish performance characteristics of PCR-based assays and
applies to newly designed or modified PCR-based assays whether they are part of an ISO method, developed
in a single laboratory (in-house) or commercially provided. These requirements address PCR-based assay
[1] [2]
performance and operate alongside the validation principles in ISO 17468 and the ISO 16140 (all parts) .
The performance characteristics of an assay shall be determined in the same way as it is intended to be used
and shall be reported with the complete analytical procedure.
For the implementation of qualitative and quantitative PCR-based assays, the performance characteristics
which are given in Table 1 should be estimated.
Table 1 — Performance characteristics for qualitative and quantitative PCR-based assays
Parameter Clause Qualitative PCR Quantitative PCR
Specificity (inclusivity/exclusivity) 4.5 x x
Dynamic range 4.6 x
Limit of detection 4.7 x x
Limit of quantification 4.8 x
Robustness 4.9 x x
Precision 4.10 x
ISO/DIS 22118:2026(en)
4.2 Scope of the PCR-based assay
The purpose of the PCR-based assay shall be indicated. Information regarding the intended use and the
limitations shall be provided. In particular, the provider of the PCR-based assay shall indicate that the
criteria set out in this International Standard are fulfilled.
4.3 General environmental laboratory requirements
The requirements regarding laboratory setup, reagents and consumables and the equipment specified in
ISO 22174 shall be followed.
4.4 Analytical controls
Analytical controls used during the PCR-step in accordance with the requirements of ISO 22174 shall be
clearly specified and their interpretation recorded. These shall include positive PCR control(s) (for all
targets in case of multiplex PCR), negative PCR control(s) and internal or external amplification control(s).
Their composition and the interpretation of each control shall be documented.
4.5 Specificity
4.5.1 General
The specificity of the PCR assay should demonstrate its ability to specifically detect the target organism in
the absence or presence of non-target organisms,including closely related organisms, and other nucleic acid
sources present in complex food matrices.
[9]
ISO 16140-2 can be used to determine the parameters inclusivity and exclusivity, in which it is stated
that each strain that is used shall be characte
...