ISO 16958:2015规定了牛奶、乳制品、婴儿配方奶粉和成人营养配方奶粉中单个和/或所有脂肪酸的定量方法，这些配方奶粉含有乳脂和/或植物油，添加或不添加富含长链多不饱和脂肪酸（LC-PUFA）的油。这还包括经常标记的脂肪酸组[即反式脂肪酸（TFA）、饱和脂肪酸（SFA）、单不饱和脂肪酸（MUFA）、多不饱和脂肪酸（PUFA）、ω-3、ω-6和ω-9脂肪酸]和/或单个脂肪酸[即亚油酸（LA）、α-亚麻酸（ALA）、花生四烯酸（ARA）]，二十碳五烯酸（EPA）和二十二碳六烯酸（DHA）]。该测定是通过在食品基质中直接酯交换进行的，无需事先提取脂肪，因此适用于液体样品或含总脂肪≥1,5%m/m的水的重组粉末样品。从中提取的脂肪含有小于1.5%m/m脂肪的产品，在使用第2条所述方法进行初步脂肪提取后，可使用相同方法进行分析。乳制品，如酸度小于等于1 mmol/100 g脂肪的软或硬奶酪，可在使用第2条所述方法进行初步脂肪提取后进行分析。对于添加或富含多不饱和脂肪酸（含鱼油或藻类）的产品，应在尽可能低的温度（例如最高40°C）下蒸发溶剂，以回收这些敏感脂肪酸。

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.