ISO/TC 34/SC 5 - Milk and milk products

This document specifies the enumeration of Pseudomonas spp. by the colony-count technique. This document is applicable to: — milk and milk products; — environmental samples in the area of dairy production and handling. The method allows the isolation of all pigmented and non-pigmented psychrotrophic Pseudomonas spp.

This document specifies methods for the extraction or separation of a representative part of the fat, containing lipids and liposoluble compounds, from milk and milk products. The method is applicable to the methods described in ISO 12078 | IDF 159, ISO 15884 | IDF 182, ISO 15885 | IDF 184 and ISO 18252 | IDF 200. NOTE Free fatty acids are not part of extracted fat as described in methods for the fat determination in milk, condensed milk, dried milk products, cream and fermented milk.

This document specifies a method for the selective enumeration of bifidobacteria in milk products by using a colony-count technique at 37 °C under anaerobic conditions. The method is applicable to milk products, such as fermented (e.g. yoghurts) and non-fermented milks (e.g. pasteurized milks, skim milks, whey protein concentrates), milk powders and formulae (e.g. infant formulae, follow-up formulae for older infants, products for young children) where these microorganisms are present and viable, in combination with other lactic acid bacteria or alone. The method is also applicable to starter and probiotic cultures. For proposed quality criteria of dairy products, see, for example, CXS 243-2003. Bifidobacteria used in milk products usually belong to the following species (e.g. References [7] and [10]): — Bifidobacterium adolescentis; — B. animalis subsp. animalis; — B. animalis subsp. lactis; — B. bifidum; — B. breve; — B. longum subsp. infantis; — B. longum subsp. longum.

This document gives guidance on the determination of total fat content in milk and milk-based products, such as milk, cream, yogurt, ice cream, processed dairy, cheese and dairy powders by low-resolution nuclear magnetic resonance (NMR) using Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence to optimize the specific response of fat molecules. This document is applicable to the analysis of any milk and milk-based products, regardless of source (species or region). It is applicable to dry samples (i.e. moisture content ≤ 10 %) and liquid or wet samples which have been pre-dried such that all appreciable water has been removed. The NMR with CPMG pulse sequence analyses glycerolipids, which produces fat results comparable to the total fat result of standard fat extraction techniques, without the need for matrix specific calibrations while meeting the precision criteria listed in Clause 12. The application is not limited by sample viscosity, colour or particle size.

This document specifies a method for the determination of β-galactooligosaccharides (GOS) in infant formula (both powder and liquid) containing 0,2 g/100 g to 3,0 g/100 g of GOS in the product as prepared ready for consumption. The method has been validated in a multi-laboratory study with reconstituted infant formula at levels of 0,236 g/100 g, 0,594 g/100 g, 0,616 g/100 g and 0,688 g/100 g and infant formula RTF at levels of 0,316 g/100 g and 0,858 g/100 g. During the single laboratory validation study[1] spike-recovery experiments were performed up to 3 g/100 g in reconstituted infant formula powders (milk-based, partially hydrolysed milk-based and soy-based), and reconstituted adult nutritional powders.

This document specifies a reference method for the determination of lactose content of raw milk, heat-treated milks, dried milk, dairy permeate, dairy permeate powder, and raw and pasteurized cream. The method does not apply to fermented milks and milks to which oligosaccharides have been added, nor to low-lactose or lactose-free milks.

This document specifies a fluorimetric method for the determination of alkaline phosphatase (ALP) (EC 3.1.3.1) activity in cheese. This method is applicable to soft cheeses, semi-hard and hard cheeses provided that the mould is only on the surface of the cheese and not also in the inner part (e.g. blue veined cheeses). For large hard cheeses, specific conditions of sampling apply (see Clause 7). The instrument used for the determination of ALP can read activities in the supernatant up to 7 000 milliunits per litre (mU/kg).

This document specifies a fluorimetric method for the determination of alkaline phosphatase (ALP) (EC 3.1.3.1) activity in raw and heat-treated whole milk, semi-skimmed milk, skimmed milk and flavoured milks. This method is applicable to milk and milk-based drinks from cows, sheep and goats. It is also applicable to milk powder after reconstitution. The instrument used for the determination of ALP can read activities up to 7 000 milliunits per litre (mU/l). If the activity is higher than 7 000 mU/l, it is diluted with ALP-free milk so as to obtain a measurement not higher than 7 000 mU/l.

This document specifies a fluorimetric microplate method for the determination of alkaline phosphatase (ALP, EC 3.1.3.1)[5] activity in raw and heat-treated whole milk, semi-skimmed milk, skimmed milk, cream, flavoured milks and cheeses. This method is applicable to milk and milk-based drinks from cows, sheep and goats. Although the method was not tested in milk from other species, it can also be applicable to milk from other species with a similar composition to cow, sheep or goat milk, such as milk from buffalo and camelids. It is also applicable to milk powder after reconstitution and soft, semi-hard and hard cheeses provided that the mould is only on the surface of the cheese and not also in the inner part (e.g. blue veined cheeses). For large hard cheeses, specific conditions of sampling apply (see Clause 7). NOTE This method was adapted from Reference [6].

This document specifies a method for the determination of the moisture content of all types of dried milk and dried milk products.

This document specifies recommended methods for the sensory evaluation of specific milk and milk products. It specifies criteria for the sampling and preparation of samples and the assessment of the samples. This document is suitable for application in conjunction with the sensory methodologies outlined in ISO 22935-1 | IDF 99-1 and other ISO or IDF sensory methodologies for specific situations and products. Annex A provides international tables of common attributes, including terms in the official ISO languages English and French as well as equivalent terms in German and Spanish.

This document gives general guidance for the recruitment, selection, training, and monitoring of assessors for sensory analysis of milk and milk products. It specifies criteria for the selection, and procedures for the training and monitoring, of selected assessors and expert sensory assessors for milk and milk products. It supplements the information given in ISO 8586 that deals with expert assessors.

This document specifies a general method for evaluation of compliance with product specifications for sensory properties based on sensory scoring and the use of a common nomenclature of terms. The method is especially applicable in process and quality control performed regularly on a larger number of samples and/or with some time pressure and/or with a limited number of expert assessors available. The results from the method can be part of product classification systems for domestic and international trade. This document does not apply to classification systems.

This document specifies a method for the determination of rheological properties by uniaxial compression at constant displacement rate in hard and semi-hard cheeses. The method provides standard conditions for sampling and testing, for data representation and general principles of calculation. NOTE Sampling can be difficult with some cheese varieties, e.g. caused by shortness, brittleness, stickiness and soft consistency. In these cases, reliable results cannot be achieved.

This document specifies a method for the quantitative determination of total amino acids using 6-aminoquinolyl-N-hydroxy-succinimidyl carbamate (ACQ) derivatization followed by ultra-high-performance liquid chromatography (UHPLC) separation and ultraviolet (UV) detection. It specifies a method for the determination, in one single analysis, of the following amino acids: alanine, arginine, aspartic acid (combined with asparagine), cystine (dimer of cysteine, combined with cysteine), glutamic acid (combined with glutamine), glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tyrosine and valine. This method does not apply to the determination of tryptophan. This method is applicable to infant and adult/paediatric nutritional formulas, dairy products and other matrices such as cereals. It was validated in infant formulas (milk- and soy-based, including partially hydrolysed and elemental products), toddler formula, adult nutritional powder, UHT skimmed milk, whey powder, sodium caseinate, whole milk powder, bran pet food, dry pet food and breakfast cereal (see Annex A for details).

This document specifies the method for the determination of fat content. The method is applicable to: a) raw milk (cow, sheep, goat), reduced fat milk, skimmed milk, chemically preserved milk and processed liquid milk; b) dried milk products (e.g. whole, partially skimmed, skimmed milk powder; dairy permeate powder; whey powder; blend skimmed milk powder and vegetable fat; milk based infant formula powder); c) raw, processed and sour cream. For the following products, the precision figures are given in Annex H. These precision figures are derived from interlaboratory studies not conforming to the requirements from ISO 5725-2 in terms of number of samples ( d) evaporated milk and sweetened condensed milk (e.g. liquid sweetened and unsweetened concentrated milk); e) whey cheese as defined in CODEX CXS 284‑1999; f) liquid whey and buttermilk; g) milk-based edible ices and ice mixes; h) liquid concentrated infant foods. The method does not apply in the following cases: — For b), when the powder contains hard lumps which do not dissolve in ammonia solution. This is noticeable by a distinct smell and the result of the determination will be too low. In such cases, a method using the Weibull-Berntrop principle is suitable, e.g. ISO 8262-3|IDF 124-3. — For c), The method is not applicable to sour creams with starch or other thickening agents. When separation or breakdown of fat occurs, a method using the Weibull-Berntrop principle is suitable, e.g. ISO 8262-3|IDF 124-3. — For e), to products which do not dissolve completely in ammonia solution, as the result of the determination will be too low. With such products, a method using the Weibull-Berntrop principle is suitable, e.g. ISO 8262-3|IDF 124-3. — For g), to milk-based edible ices and ice mixes in which the level of emulsifier, stabilizer or thickening agent or of egg yolk or of fruits, or of combinations of these constituents, makes the Röse-Gottlieb method unsuitable. With such products, a method using the Weibull-Berntrop principle is suitable, e.g. ISO 8262-2|IDF 124-2. — For h), to products which do not dissolve completely in ammonia due to the presence of starch or dextrin at mass fractions of more than 5 % (in dry matter), or to the presence of hard lumps. For such products, a method using the Weibull-Berntrop principle is suitable, e.g. ISO 8262-1|IDF 124-1.

This document specifies a protocol for the evaluation and validation of alternative quantitative methods of milk analysis. This document is also applicable for the validation of new alternative methods where, due to a limited number of operational instruments, the execution of an interlaboratory study and ISO 8196-1 | IDF 128-1 is not feasible. The protocol is applicable to milk parameters such as, for example, fat, protein, lactose, urea and somatic cells in milk. It can also be extended to other parameters. This document also establishes the general principles of a procedure for granting international approvals for the performance of the alternative methods. These principles are based on the validation protocol defined in this document.

This document specifies a method for the determination of the fat content of all types of cheese and processed cheese products containing lactose of below 5 % (mass fraction) of non-fat solids, and all types of caseins and caseinates. The method is not applicable to fresh cheese types containing, for example, fruits, syrup or muesli. For such products, the Schmid-Bondzynski-Ratzlaff (SBR) principle is not applicable due to high concentrations of sugars. For these products, the method using the Weibull-Berntrop principle (see ISO 8262-3 | IDF 124-3) is appropriate.

This document gives guidance on the sample preparation of fresh cheese, (semi)soft cheese, (semi)hard cheese, processed cheese and whey cheese for physical and chemical analysis, including analysis by applying instrumental methods. This document describes the (sub)sampling, and sample preparation steps carried out after sampling according to ISO 707 | IDF 50 and prior to method-specific sample preparations, e.g. as with analytical methods listed in References [2] to [22]. NOTE Analysis on volatile substances, minor components or allergens can require additional precautionary measures in sample preparation in order to avoid loss of or contamination with one or more target analytes.

This document specifies a method for the determination of melamine and cyanuric acid with liquid chromatography in combination with tandem mass spectrometry (LC-MS/MS). The method has been validated in an interlaboratory study via the analysis of spiked samples of milk-based infant formula, soy-based infant formula, milk powder, whole milk, soy drink and milk chocolate ranging from 0,71 mg/kg to 1,43 mg/kg for melamine and 0,57 mg/kg to 1,45 mg/kg for cyanuric acid. The limits of quantification (LOQ) for melamine and cyanuric acid in food are 0,05 mg/kg and 0,25 mg/kg, respectively. The upper limit of the working range is up to 10 mg/kg for melamine and up to 25 mg/kg for cyanuric acid.

This document describes general workflows and protocols for the validation and the verification of qualitative screening tests for the detection of residues of veterinary drugs in liquid milk (raw, pasteurized, UHT and reconstituted milk powders and whey protein extracts) including biological methods. This guideline does not cover the validation of residue analysis by HPLC, UHPLC or LC-MS/MS. This document is intended to be useful for manufacturers of screening test kits, laboratories validating screening methods or tests, competent authorities and dairies or end users of reagents or tests for the detection of veterinary drug residues in milk products. This document facilitates and improves the validation and verification of screening methods. The goals of this document are a harmonization in validation of methods or test kits in order for all stakeholders to have full trust in the result of residue screening and to limit the overlap and multiplication of validation work in different laboratories by sharing the validation results generated by an independent laboratory. Furthermore, a harmonized validation and verification procedure allows for comparison of the performance of different screening methods. This document does not imply that all end users are bound to perform all verification work proposed. The verification of the correct use of reagents/kits for the detection of antimicrobials is not part of the scope of this document.

This document specifies a method for the determination of aflatoxin M1 content in milk and milk powder. The lowest level of validation is 0,08 µg/kg for whole milk powder, i.e. 0,008 µg/l for reconstituted liquid milk. The limit of detection (LOD) is 0,05 μg/kg for milk powder and 0,005 μg/kg for liquid milk. The limit of quantification (LOQ) is 0,1 μg/kg for milk powder and 0,01 μg/kg for liquid milk. The method is also applicable to low-fat milk, skimmed milk, low-fat milk powder and skimmed milk powder.

This document gives guidelines for the establishment of a conversion relationship between the results of an alternative method and an anchor method, and its verification for the quantitative determination of the microbiological quality of milk. NOTE The conversion relationship can be used a) to convert results from an alternative method to the anchor basis or b) to convert results/limits, expressed on an anchor basis, to results in units of an alternative method.

This document specifies the quantitative liquid chromatographic determination of specific sugars (galactose, glucose, fructose, sucrose, lactose and maltose) in various milk and milk products, applying arabinose as an internal standard. The method is applicable to the following dairy matrices: milk, sweetened condensed milk, milk powder, cheese, whey powder, infant formula, milk dessert and yoghurt. The method does not apply to dairy products containing soy or to the determination of the lactose content in low-lactose milk products at levels below 1 mg/g. A high performance anion exchange chromatography method in combination with pulsed amperometric detection (HPAEC-PAD) method is applied[5][3][4]. With this method, thirteen different monosaccharides, disaccharides and trisaccharides can be separated: fucose, arabinose, galactose, glucose, fructose, sucrose, lactose, lactulose, maltose, melibiose, trehalose, isomaltulose and maltotriose. The method is applicable to labelling for the six most important sugars that can be present by nature or by addition in milk and milk products. The method does not apply to sugar contents less than 0,1 %.

This document gives guidelines for the use of near infrared (NIR) spectrometry in the analysis of milk and milk products in liquid, semi-solid or solid form. Depending on the sample form and application, different instrument setups for transmittance, diffuse reflectance or transflectance can be applied.

This document specifies a liquid chromatography tandem mass spectrometry (LC?MS/MS) method for the quantification of the inhibitory substance, nitrofurazone, in milk and milk products. The method has been validated for measuring trace levels of intact nitrofurazone to levels down to 1 ng/g in fluid milk and powdered dairy products on a whole product (i.e. powder) basis. While the method is expected to apply to other dairy matrices, additional validation will be required to demonstrate this.

This document specifies a method for the determination of inulin-type fructans (including oligofructose, fructooligosaccharides) in infant formula and adult nutritionals (both powder and liquid) containing 0,03 g/100 g to 5,0 g/100 g of fructans in the product as prepared ready for consumption. The method has been validated in a multi laboratory study[1] with reconstituted standard reference material (SRM), infant/adult nutritional formula at a level of 0,204 g/100 g, adult nutritionals ready-to-feed (RTF) at levels of 1,28 g/100 g and 2,67 g/100 g, infant formula RTF at a level of 0,300 g/100 g, reconstituted follow-up formula at levels of 0,209 g/100 g to 0,275 g/100 g, reconstituted infant formula at levels from 0,030 8 g/100 g to 0,264 g/100 g. During the single laboratory validation study[2], spike-recovery experiments were performed up to 5 g/100 g in reconstituted infant formula powders (milk-based, partially hydrolysed milk-based and soy-based), adult nutritional RTF and reconstituted adult nutritional powders.

This document specifies a method for the determination of the whey to casein protein ratio, ranging from 20:80 to 80:20 in cow milk-based infant formula powders. This method does not apply to the analysis of infant formulas containing hydrolysed protein or proteins from other sources (e.g. plants or milk from other mammals).

This document gives guidelines for using infrared spectrometry in in-line and on-line applications for dairy processing. These applications are distinct to those covered in ISO 21543 | IDF 201. It is applicable, but not limited, to: — the determination of protein, fat and total solids in liquid milk and milk products using mid and near infrared spectrometry; — the determination of protein, fat and moisture in solid or semi-solid products, such as milk powder, and butter and liquid dairy streams using near infrared spectrometry.

This document specifies a protocol for the evaluation of instrumental alternative methods for total bacterial count in raw milk from animals of different species. NOTE The document is complementary to ISO 16140-2 and ISO 8196 | IDF 128 (all parts).

This document specifies a reference method for the determination of milk fat purity using gas chromatographic analysis of triglycerides. The method utilizes the differences in triglyceride fingerprint of milk fat from the individual triglyceride fingerprints of other fats and oils to determine samples which are outside the range normally observed for milk fat. This is achieved by using the defined triglyceride formulae based on the normalized weighted sum of individual triglyceride peaks which are sensitive to the integrity of the milk[6][7]. The integrity of the milk fat can be determined by comparing the result of these formulae with those previously observed for a range of pure milk fat samples[12]. Both vegetable fats and animal fats such as beef tallow and lard can be detected. The method is applicable to bulk milk, or products made thereof, irrespective of the variation in common feeding practices, breed or lactation conditions. In particular, the method is applicable to fat extracted from milk products purporting to contain pure milk fat with unchanged composition, such as butter, cream, milk and milk powder. Because a false-positive result can occur, the method does not apply to milk fat related to these circumstances: a) obtained from bovine milk other than cow's milk; b) obtained from single cows; c) obtained from cows whose diet contained a particularly high proportion of vegetable oils such as rapeseed, cotton or palm oil, etc.; d) obtained from cows suffering from serious underfeeding (strong energy deficit); e) obtained from colostrum; f) subjected to technological treatment such as removal of cholesterol or fractionation; g) obtained from skim milk, buttermilk or whey; h) obtained from cheeses showing increased lipolysis; i) extracted using the Gerber, Weibull?Berntrop or Schmid?Bondzynski?Ratzlaff methods, or that has been isolated using detergents (e.g. the Bureau of Dairy Industries method). With the extraction methods specified in i), substantial quantities of partial glycerides or phospholipids can pass into the fat phase. NOTE 1 In nature, butyric (n-butanoic) acid (C4) occurs exclusively in milk fat and enables quantitative estimations of low to moderate amounts of milk fat in vegetable and animal fats to be made. Due to the large variation of C4, for which the approximate content ranges from 3,1 % fat mass fraction to 3,8 % fat mass fraction, it is difficult to provide qualitative and quantitative information for foreign fat to pure milk fat ratios of up to 20 % mass fraction[11]. NOTE 2 In practice, quantitative results cannot be derived from the sterol content of vegetable fats, because they depend on production and processing conditions. Furthermore, the qualitative determination of foreign fat using sterols is ambiguous. NOTE 3 Due to special feeding practices such as those related to c) and d), false-positive results have sometimes been reported for milk from certain Asian regions[15]. Moreover, grass-only diets such as mountain and, in particular, highland pasture feeding sometimes cause false-positive results, which can be substantiated by a content of conjugated linoleic acid (C18:2 c9t11) of ≥ 1,3 % fatty acid mass fraction[16][17]. Nevertheless, results conforming to the criteria of milk fat purity specified in this document are accepted, even if samples were undoubtedly produced under conditions reported in this note, including those described in h). NOTE 4 In cases where a positive result is suspected to be caused by circumstances related to c) or d), another analytical method, such as fatty acid or sterol analysis, can be applied to confirm the finding. Due to similar or increased limitations (e.g. as described in NOTE 1 and NOTE 2), a negative result obtained by another method is not appropriate to contrastingly confirm milk fat purity.

Le présent document spécifie une méthode de détermination quantitative de la teneur en calcium (Ca), cuivre (Cu), fer (Fe), magnésium (Mg), manganèse (Mn), phosphore (P), potassium (K), sodium (Na) et zinc (Zn) par spectrométrie d'émission atomique avec plasma induit par haute fréquence (ICP-AES). La méthode est applicable au lait, au lait en poudre, au beurre, au fromage, au lactosérum, au lactosérum en poudre, aux formules infantiles et aux produits nutritionnels pour adultes dans les plages données dans le Tableau 1.

This document specifies a method for the quantitative determination of calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), phosphorus (P), potassium (K), sodium (Na), zinc (Zn), chromium (Cr), molybdenum (Mo) and selenium (Se) using inductively coupled plasma and mass spectrometry (ICP-MS). The method is applicable for the determination of all 12 elements in infant formula and adult nutritional products. The method is also applicable for milk, milk powder, whey powder, butter and cheese excluding the determination of Cr, because all Cr results were below the quantification limit and reproducibility could not be determined in these matrices[1]. The present method is an extension of ISO 20649 | IDF 235 (AOAC 2011.19[2]) which was validated only for Cr, Mo and Se in infant formula and adult nutritional products.

This document specifies a method for the determination of chloride in milk, milk products, infant formula and adult nutritionals by potentiometry[1][2][3][4] with an analytical range of 0,35 mg chloride/100 g to 711,6 mg chloride/100 g product, or ready-to-feed products.

ISO 9233-1 | IDF 140-1:2018 specifies a method for the determination in cheese rind of natamycin mass fraction of above 0,5 mg/kg and surface-area-related natamycin mass of above 0,03 mg/dm2. NOTE It is possible that the method is suitable for detecting migration of natamycin into the cheese.

ISO 9233-2 | IDF 140-2:2018 specifies a method for the determination of natamycin mass fraction in cheese, cheese rind and processed cheese of above 0,5 mg/kg and of the surface-area-related natamycin mass in cheese rind of above 0,03 mg/dm2.

ISO 196660 | IDF 237:2018 specifies an acidobutyrometric method for determining the fat content of cream. The reference method remains the gravimetric method (by ammoniacal ether extraction) described in ISO 2450 | IDF 16. This method is applicable to cream having a fat content between 20 % and 50 % inclusive: - intended for manufacturing butter; - sweet, unmatured and non-inoculated; - raw or having undergone a heat treatment; - non-homogenized; - with or without preservatives (2-bromo-2-nitropropane, 1,3 diol or bronopol).

ISO 19662 | IDF 238:2018 specifies a method, the acido-butyrometric or "Gerber", for determining the fat content of milk. It is applicable to whole milk and partially skimmed milk. It is also applicable to milk containing authorized preservatives (potassium dichromate, bronopol). It does not apply to formalin milk, nor to milks that have undergone a homogenisation treatment.

ISO/TS 19046-1| IDF/RM 233-1:2017 specifies a method for the determination of propionic acid level in cheese, using gas chromatography.

ISO/TS 19046-2 | IDF/RM 233-2:2017 specifies a method for the determination of propionic acid level in cheese, using ion exchange chromatography.

ISO 8968-4|IDF 20-4:2016 specifies a method for the direct and indirect determination of the protein nitrogen content of liquid, whole or skimmed milk.

ISO 27105:2016 specifies a method for the quantitative determination of hen's egg white lysozyme content in milk and cheese. The method is suitable for measuring low levels of hen's egg white lysozyme with a quantification limit of 10 mg/kg.

ISO 19344:2015 specifies a standardized method for the quantification of active and/or total lactic acid bacteria and probiotic strains in starter cultures used in dairy products by means of flow cytometry. The method is also applicable to probiotics used in dairy products and to fermented milk products such as yogurts containing primarily lactic acid bacteria. This International Standard does not apply to taxonomical differentiation of bacteria. Due to its non-specificity, the method may quantify other bacteria than those within the scope of this International Standard, when present in the sample. This may lead to overestimation of the counts. The minimum bacterial cell concentration in the sample before applying this standardized method depends on the dilution rates used in the individual protocols. Typically 106 cells per gram or ml are considered within the minimum range.

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.

ISO 20649:2015 specifies a method for the quantitative determination of chromium, selenium and molybdenum in infant formula and adult nutritional formula.[1] The method has been validated in an interlaboratory study on seven different matrices.

ISO 20647:2015 specifies a method for the quantitative determination of total iodine in infant formula and adult nutritional formula.[1] The method is applicable to the measurement of total iodine in infant formula and adult nutritional formula from 0,5 µg/100g to 1 500 µg/100g reconstituted final product and for ready-to-feed products from 2,5 µg/100 g to 1 000 µg/100 g using ICP-MS. Using various infant formula and adult nutritional products, the method was subjected to an interlaboratory study. Levels obtained ranged from 3,47 µg/100 g to 124 µg/100 g. For all precision data related to the interlaboratory study, see Table A.1 located in Annex A.

ISO/TS 17758|IDF/RM 87:2014 specifies a method for the determination of the dispersibility in water of instant dried milk. The method is applicable to instant dried skimmed milk manufactured by either the "straight-through" or the "re-wet" process and also to instant dried whole milk.

ISO 8968-1|IDF 20-1:2014 specifies a method for the determination of the nitrogen content and crude protein calculation of milk and milk products by the Kjeldahl principle, using traditional and block digestion methods. The methods are applicable to: liquid cow's (whole, partially skimmed or skimmed milk), goat's and sheep's whole milk; hard, semi-hard and processed cheese; dried milk and dried milk products (including milk-based infant formulae, milk protein concentrate, whey protein concentrate, casein and caseinate). The methods are not applicable to samples containing ammonium caseinate.

ISO 9622|IDF 141:2013 gives guidelines for the quantitative compositional analysis of milk and liquid milk products, such as raw milk, processed milk, cream and whey, by measurement of the absorption of mid-infrared radiation. Additional built-in instrument features, such as a conductivity sensor, can improve the performance in the determination of compositional parameters and allow for the estimation of other parameters. The guidelines specified are applicable to the analysis of cow's milk. The guidelines are also applicable to the analysis of milk of other species (goat, ewe, buffalo, etc.) and derived liquid milk products, provided adequate calibrations are generated for each application and adequate control procedures are in place.