ISO 16958-2015 PDF

Full title and description

ISO 16958:2015 (IDF 231:2015) — Milk, milk products, infant formula and adult nutritionals — Determination of fatty acids composition — Capillary gas chromatographic method. This joint ISO/IDF method specifies a validated procedure to prepare samples by direct transesterification, produce fatty acid methyl esters (FAMEs) and separate/quantify them by capillary gas chromatography for individual fatty acids and summed classes (e.g. TFA, SFA, MUFA, PUFA, omega‑3/6/9).

Abstract

Provides a laboratory method to determine the fatty acid profile of milk, milk products, infant formula and adult nutritionals, including quantification of key fatty acids (LA, ALA, ARA, EPA, DHA) and grouped totals. The method is applicable without prior fat extraction for liquid or reconstituted powder samples having total fat ≥ 1.5 % m/m; products with lower fat or certain cheeses require preliminary fat extraction. Recommendations are included for preserving long‑chain PUFA during solvent evaporation.

General information

• Status: Withdrawn (replaced by a revised ISO 16958, published 2026).
• Publication date: First edition published November 2015 (2015-11, edition 1).
• Publisher: International Organization for Standardization (ISO), published jointly with the International Dairy Federation (IDF); method equivalent to AOAC Official Method 2012.13 (also published by AOAC).
• ICS / categories: 67.100 (Milk and milk products); related analytical ICS areas (physicochemical methods) also apply.
• Edition / version: Edition 1 (2015).
• Number of pages: 45 pages.

Scope

Specifies a capillary gas‑chromatographic method (after transesterification to FAMEs) for the quantification of individual and grouped fatty acids in milk, milk products, infant formula and adult nutritional formulas that contain milk fat and/or vegetable oils, including products supplemented with long‑chain PUFA. It defines sample preparation routes for samples with ≥ 1.5 % fat (direct transesterification) and gives requirements/references for preliminary fat extraction where needed. Guidance is provided on reagents, apparatus, chromatographic conditions and performance checks.

Key topics and requirements

• Analytical principle: direct transesterification of the food matrix to produce FAMEs, followed by capillary gas chromatography (GC) separation and quantification.
• Scope of samples: liquid and reconstituted powders with total fat ≥ 1.5 % m/m (no prior extraction); products < 1.5 % m/m and certain cheeses require preliminary fat extraction.
• Measured analytes: individual fatty acids (including LA, ALA, ARA, EPA, DHA) and grouped sums (TFA, SFA, MUFA, PUFA, omega‑3/6/9).
• Quality and performance controls: specification of internal standards, calibration, chromatographic resolution criteria and suggested FAME standards.
• Special precautions: procedures to minimise loss/degradation of LC‑PUFA (e.g. control of evaporation temperatures), and guidance on chromatographic column selection and method tuning.
• References and equivalence: method is equivalent to AOAC Official Method 2012.13 and has been adopted in related regional standards.

Typical use and users

Routine and reference laboratories in the dairy industry, infant‑formula and nutritional product manufacturers, food control and regulatory laboratories, quality assurance teams, method validation groups, and academic researchers working on milk fat composition and nutritional labelling. The method is used for product development, compliance testing, labelling verification and research into fatty‑acid profiles.

Related standards

AOAC Official Method 2012.13 (equivalent procedure); ISO/IDF standards on sampling and lipid extraction referenced in the method (for example ISO 707 for sampling and ISO 14156/IDF 172 for extraction methods); the revised ISO 16958 (edition 2, 2026) which supersedes the 2015 edition. Regional adoptions (e.g. EN ISO adoption) also exist.

Keywords

fatty acids, FAME, capillary gas chromatography, milk, milk products, infant formula, adult nutritionals, transesterification, LC‑PUFA, AOAC, IDF, milk fat composition.

FAQ

Q: What is this standard?

A: An ISO/IDF analytical standard (ISO 16958:2015 / IDF 231:2015) that specifies a capillary GC method for determining the fatty acid composition of milk, milk products, infant formula and adult nutritionals.

Q: What does it cover?

A: The method covers sample preparation (direct transesterification for most liquid/reconstituted samples), production of fatty acid methyl esters (FAMEs), GC separation/quantification of individual fatty acids and summed classes, quality controls and precautions for labile long‑chain PUFAs. It also references when preliminary fat extraction is required.

Q: Who typically uses it?

A: Dairy and nutritional product testing laboratories, food regulators, product manufacturers and researchers conducting compositional analysis, labelling verification or method validation.

Q: Is it current or superseded?

A: ISO 16958:2015 has been withdrawn and replaced by a revised ISO 16958 (edition 2) published in January 2026; laboratories should use the 2026 edition for current requirements. The 2015 edition remains a historical reference but is superseded.

Q: Is it part of a series?

A: It is part of ISO/IDF joint analytical methods for milk and milk products (ISO/TC 34/SC 5 and IDF publications) and is cross‑referenced with sampling and lipid extraction standards used in dairy analysis.

Q: What are the key keywords?

A: Fatty acids, FAME, capillary GC, milk, infant formula, adult nutritionals, transesterification, LC‑PUFA, AOAC equivalence.