ISO/FDIS 16958
(Main)Milk, milk products, infant formula and adult nutritionals — Determination of fatty acids composition — Capillary gas chromatographic method
Milk, milk products, infant formula and adult nutritionals — Determination of fatty acids composition — Capillary gas chromatographic method
ISO 16958:2015 specifies a method for the quantification of individual and/or all fatty acids in the profile of milk, milk products, infant formula and adult nutritional formula, containing milk fat and/or vegetable oils, supplemented or not supplemented with oils rich in long chain polyunsaturated fatty acids (LC-PUFA). This also includes groups of fatty acids often labelled [i.e. trans fatty acids (TFA), saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), omega-3, omega-6 and omega-9 fatty acids] and/or individual fatty acids [i.e. linoleic acid (LA), α-linolenic acid (ALA), arachidonic acid (ARA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)]. The determination is performed by direct transesterification in food matrices, without prior fat extraction, and consequently it is applicable to liquid samples or reconstituted powder samples with water having total fat ≥ 1,5 % m/m. The fat extracted from products containing less than 1,5 % m/m fat can be analysed with the same method after a preliminary fat extraction using methods referenced in Clause 2. Dairy products, like soft or hard cheeses with acidity level ≤ 1 mmol/100 g of fat, can be analysed after a preliminary fat extraction using methods referenced in Clause 2. For products supplemented or enriched with PUFA with fish oil or algae origins, the evaporation of solvents should be performed at the lowest possible temperature (e.g. max. 40 °C) to recover these sensitive fatty acids.
Lait, produits laitiers, formules infantiles et produits nutritionnels pour adultes — Détermination de la composition en acides gras — Méthode de chromatographie en phase gazeuse sur colonne capillaire
ISO 16958:2015 spécifie une méthode de quantification des acides gras individuels et/ou de tous les acides gras dans le profil du lait, des produits laitiers, des formules infantiles et des préparations nutritionnelles pour adultes contenant de la matière grasse de lait et/ou des huiles végétales, supplémentées ou non supplémentées avec des huiles riches en acides gras polyinsaturés à chaîne longue (AGPI-CL). Cela inclut également les groupes d'acides gras souvent déclarés [c'est-à-dire, les acides gras trans (AGT), les acides gras saturés (AGS), les acides gras monoinsaturés (AGMI), les acides gras polyinsaturés (AGPI), les acides gras oméga-3, oméga-6 et oméga-9] et/ou les acides gras individuels [c'est-à-dire l'acide linoléique (AL), l'acide α-linolénique (AAL), l'acide arachidonique (ARA), l'acide éicosapentaénoïque (AEP), l'acide docosahexaénoïque (ADH)]. La détermination est effectuée par transestérification directe dans les matrices d'aliments, sans extraction préalable de la matière grasse. Elle s'applique donc aux échantillons liquides ou aux échantillons pulvérulents reconstitués avec de l'eau et ayant une teneur totale en matière grasse supérieure ou égale à 1,5 % (m/m). La matière grasse extraite de produits contenant moins de 1,5 % (m/m) de matière grasse peut être analysée avec la même méthode après une extraction préalable de la matière grasse en utilisant les méthodes référencées dans l'Article 2 Les produits laitiers tels que les fromages à pâte molle ou à pâte dure ayant un niveau d'acidité inférieur ou égal à 1 mmol/100 g de matière grasse peuvent être analysés après une extraction préalable de la matière grasse en utilisant les méthodes référencées dans l'Article 2. Pour les produits supplémentés ou enrichis en AGPI extrait d'huile de poisson ou d'algues, il convient que l'évaporation de solvants soit effectuée à la plus faible température possible (par exemple, 40 °C maximum) pour récupérer ces acides gras sensibles.
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Standards Content (Sample)
FINAL DRAFT
International
Standard
ISO/TC 34/SC 5
Milk, milk products, infant
Secretariat: NEN
formula and adult nutritionals —
Voting begins on:
Determination of fatty acids
composition — Capillary gas
Voting terminates on:
chromatographic method
Lait, produits laitiers, formules infantiles et produits nutritionnels
pour adultes — Détermination de la composition en acides gras
— Méthode de chromatographie en phase gazeuse sur colonne
capillaire
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 SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
ISO/CEN PARALLEL PROCESSING LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
231:2025(en) © ISO and IDF 2025
FINAL DRAFT
International
Standard
IDF 231
ISO/TC 34/SC 5
Milk, milk products, infant
Secretariat: NEN
formula and adult nutritionals —
Voting begins on:
Determination of fatty acids
composition — Capillary gas
Voting terminates on:
chromatographic method
Lait, produits laitiers, formules infantiles et produits nutritionnels
pour adultes — Détermination de la composition en acides gras
— Méthode de chromatographie en phase gazeuse sur colonne
capillaire
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
© ISO and IDF 2025
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
IN ADDITION TO THEIR EVALUATION AS
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
ISO/CEN PARALLEL PROCESSING
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
or ISO’s member body in the country of the requester.
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
ISO copyright office International Dairy Federation TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
CP 401 • Ch. de Blandonnet 8 Silver Building • Bd Auguste Reyers 70/B
CH-1214 Vernier, Geneva B-1030 Brussels
Phone: +41 22 749 01 11 Phone: +32 2 325 67 40
Fax: +32 2 325 67 41
Email: copyright@iso.org Email: info@fil-idf.org
Website: www.iso.org Website: www.fil-idf.org
Reference number
Published in Switzerland
IDF 231:2025(en)
ii
IDF 231:2025(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Reagents . 2
6 Apparatus . 6
7 Sampling . 8
8 Preparation of test sample . 9
8.1 Liquid and powder milk and infant formula with a fat content ≥ 1,5 % (mass fraction) .9
8.2 Liquid and powder milk and infant formula with a fat content < 1,5 % (mass fraction) .9
8.3 Cheese .9
9 Procedure . 9
9.1 Test portion .9
9.2 Quantitative determination .10
9.2.1 Determination of response factors .10
9.2.2 Determination of the test portion .10
9.2.3 Fatty acid identification .10
10 Calculation and expression of results .12
10.1 Calculation . 12
10.1.1 Calculation of response factor . 12
10.1.2 Fatty acids on the product . 12
10.1.3 Fatty acids on the total fat . 13
10.1.4 Sum of class or group of fatty acids in 100 g product . 13
10.1.5 Sum of class or group of fatty acids in 100 g fat . 13
10.1.6 Performance of the transesterification . 13
10.2 Expression of results . .14
11 Precision . 14
11.1 Interlaboratory test . .14
11.2 Repeatability .14
11.3 Reproducibility . 15
11.4 Limit of detection (LOD) . 15
11.5 Limit of quantitation (LOQ) . 15
12 Test report .15
Annex A (normative) Groups or classes of fatty acids and individual fatty acids .16
Annex B (normative) Gas–liquid chromatographic analysis . 19
Annex C (informative) Results of an interlaboratory trial .29
Bibliography .45
iii
IDF 231:2025(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 document 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 5, Milk and
milk products, and the International Dairy Federation (IDF), in collaboration with AOAC INTERNATIONAL,
and in collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/
TC 302, Milk and milk products - Methods of sampling and analysis,in accordance with the Agreement on
technical cooperation between ISO and CEN (Vienna Agreement). It is being published jointly by ISO and
IDF and separately by AOAC INTERNATIONAL. The method described in this International Standard is
equivalent to the AOAC Official Method 2012.13: Determination of labeled fatty acids content in milk products
and infant formula.
This second edition cancels and replaces the first edition (ISO 16958 | IDF 231:2015), of which it constitutes
a minor revision.
The changes are as follows:
— references to other standards have been updated;
— information on standard solutions and chromatographic columns has been updated;
— the Bibliography has been expanded.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
IDF 231:2025(en)
IDF (the International Dairy Federation) is a non-profit private sector organization representing the
interests of various stakeholders in dairying at the global level. IDF members are organized in National
Committees, which are national associations composed of representatives of dairy-related national interest
groups including dairy farmers, dairy processing industry, dairy suppliers, academics and governments/
food control authorities.
ISO and IDF colla
...
TC /SC
Date: 2025-05-20
ISOISO/FDIS 16958 | :2025(en)
IDF 231:2025(Een)
ISO/TC /34/SC /5/WG
Secretariat: NEN
Date: 2025-08-28
Milk, milk products, infant formula and adult nutritionals —
Determination of fatty acids composition — Capillary gas
chromatographic method
Lait, produits laitiers, formules infantiles et produits nutritionnels pour adultes — Détermination de
la composition en acides gras — Méthode de chromatographie en phase gazeuse sur colonne
capillaire
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 International Dairy Federation
CP 401 • Ch. de Blandonnet 8 Silver Building • Bd Auguste Reyers 70/B
CH-1214 Vernier, Geneva B-1030 Brussels
Phone: +41 22 749 01 11 Phone: + 32 2 325 67 40
Email: copyright@iso.org Fax: + 32 2 325 67 41
Website: www.iso.org Email: info@fil-idf.org
Website: www.fil-idf.org
Published in Switzerland
Contents
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Reagents . 2
6 Apparatus . 6
7 Sampling . 9
8 Preparation of test sample . 10
8.1 Liquid and powder milk and infant formula with a fat content ≥ 1,5 % (mass fraction) . 10
8.2 Liquid and powder milk and infant formula with a fat content < 1,5 % (mass fraction) . 10
8.3 Cheese . 10
9 Procedure . 10
9.1 Test portion . 10
9.2 Quantitative determination . 11
9.2.1 Determination of response factors . 11
9.2.2 Determination of the test portion . 11
9.2.3 Fatty acid identification . 11
10 Calculation and expression of results . 13
10.1 Calculation . 13
10.1.1 Calculation of response factor . 13
10.1.2 Fatty acids on the product . 14
10.1.3 Fatty acids on the total fat . 15
10.1.4 Sum of class or group of fatty acids in 100 g product . 15
10.1.5 Sum of class or group of fatty acids in 100 g fat . 15
10.1.6 Performance of the transesterification . 15
10.2 Expression of results . 16
11 Precision . 16
11.1 Interlaboratory test . 16
11.2 Repeatability. 16
11.3 Reproducibility . 17
11.4 Limit of detection (LOD) . 17
11.5 Limit of quantitation (LOQ) . 17
12 Test report . 17
Annex A (normative) Groups or classes of fatty acids and individual fatty acids . 18
Annex B (normative) Gas–liquid chromatographic analysis . 23
Annex C (informative) Results of an interlaboratory trial . 37
Bibliography . 55
iii
ForewordsForeword
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 documentsdocument 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).
Attention is drawnISO draws attention to the possibility that some of the elementsimplementation of this
document may beinvolve the subjectuse 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. Details of any patent rights identified during the development of the
document will be in the Introduction and/or on the ISO list of patent declarations received (see ).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation onof 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.htmlthe following URL: .
The committee responsible for thisThis document iswas prepared by Technical Committee ISO/TC 34, Food
products, Subcommittee SC 5, Milk and milk products, and the International Dairy Federation (IDF), in
collaboration with AOAC INTERNATIONAL., and in collaboration with the European Committee for
Standardization (CEN) Technical Committee CEN/TC 302, Milk and milk products - Methods of sampling and
analysis, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna
Agreement). It is being published jointly by ISO and IDF and separately by AOAC INTERNATIONAL. The
method described in this International Standard is equivalent to the AOAC Official Method 2012.13:
Determination of labeled fatty acids content in milk products and infant formula.
This second edition cancels and replaces the first edition (ISO 16958 | IDF 231:2015), of which has
undergoneit constitutes a minor revision.
The main changes are as follows:
— references to other standards have been updated;
— information on standard solutions and chromatographic columns has been updated;
— the Bibliography has been expanded.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
IDF (the International Dairy Federation) is a non-profit private sector organization representing the
interests of various stakeholders in dairying at the global level. IDF members are organized in National
Committees, which are national associations composed of representatives of dairy-related national interest
groups including dairy farmers, dairy processing industry, dairy suppliers, academics and
governments/food control authorities.
ISO and IDF collaborate closely on all matters of standardization relating to methods of analysis and sampling
for milk and milk products. Since 2001, ISO and IDF jointly publish their International Standards using the
logos and reference numbers of both organizations.
Attention is drawnIDF draws attention to the possibility that some of the elementsimplementation of this
document may beinvolve the subjectuse of (a) patent(s). IDF 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, IDF 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. IDF shall not be held responsible for
identifying any or all such patent rights. Details of any patent rights identified during the development of the
document will be in the Introduction and/or on the ISO list of patent declarations received (see ).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
ISO 16958 | IDF 231This document was prepared by the IDF Standing Committee on Analytical Methods for
Composition and the ISO Technical Committee ISO/TC 34, Food products, Subcommittee SC 5 on, Milk and
milk products (ISO/TC 34/SC 5),, in collaboration with AOAC INTERNATIONAL. It is being published jointly
by ISO and IDF, and separately by AOAC INTERNATIONAL. The method described in this International
Standard is equivalent to the AOAC Official Method 2012.13: Determination of labeled fatty acids content in
milk products and infant formula
All work was carried out by the ISO-IDF Project Group C11 of the Standing Committee on Analytical Methods
for Composition under the aegis of its project leader, Mr Pierre-Alain Golay (CH).
v
FINAL DRAFT International Standard ISO/FDIS 16958:2025(en)
IDF 231:2025(en)
Milk, milk products, infant formula and adult nutritionals —
Determination of fatty acids composition — Capillary gas
chromatographic method
1 Scope
This document specifies a met
...
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