ISO 23318:2022
(Main)Milk, dried milk products and cream — Determination of fat content — Gravimetric method
Milk, dried milk products and cream — Determination of fat content — Gravimetric method
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.
Lait, produits laitiers secs et crème — Détermination de la teneur en matière grasse — Méthode gravimétrique
Le présent document spécifie la méthode de détermination de la teneur en matière grasse. La méthode est applicable: a) au lait cru (vache, brebis, chèvre), au lait allégé en matière grasse, au lait écrémé, au lait conservé chimiquement et au lait liquide ayant subi un traitement; b) aux produits laitiers secs (par exemple, lait en poudre entier, partiellement écrémé, écrémé; perméat de lait en poudre; lactosérum en poudre; mélange de lait en poudre et matière grasse végétale; formule infantile à base de lait en poudre); c) à la crème crue, à la crème ayant subi un traitement et à la crème aigre; Pour les produits ci-après, les données de fidélité sont fournies à l’Annexe H. Ces données de fidélité sont issues d’études interlaboratoires non conformes aux exigences de l’ISO 5725-2 en ce qui concerne le nombre d’échantillons ( d) au lait évaporé et au lait concentré sucré (par exemple, lait concentré liquide sucré et non sucré); e) au fromage de sérum, tel que défini dans le CODEX CXS 284‑1999; f) au sérum liquide et au babeurre; g) aux glaces et mélanges de glaces de consommation à base de lait; h) aux aliments concentrés liquides pour nourrissons. La méthode ne s’applique pas dans les cas suivants: — pour b), lorsque la poudre contient des grumeaux qui ne se dissolvent pas dans une solution d’hydroxyde d’ammonium, auquel cas une odeur caractéristique se dégage et le résultat de la détermination est trop bas. Dans ces situations, une méthode utilisant le principe de Weibull-Berntrop est adaptée, par exemple l’ISO 8262-3|FIL 124-3; — pour c), la méthode n’est pas applicable aux crèmes aigres contenant de l’amidon ou d’autres agents épaississants. Lorsqu’une séparation ou une dégradation de la matière grasse se produit, une méthode utilisant le principe de Weibull-Berntrop est adaptée, par exemple l’ISO 8262-3|FIL 124-3; — pour e), les produits qui ne se dissolvent pas complètement dans une solution d’hydroxyde d’ammonium, donnant lieu à un résultat de détermination trop bas. Dans le cas de ces produits, une méthode utilisant le principe de Weibull-Berntrop est adaptée, par exemple l’ISO 8262-3|FIL 124-3; — pour g), les glaces et mélanges de glaces de consommation à base de lait dans lesquels le taux d’émulsifiant, de stabilisant ou d’agent épaississant, ou de jaune d’œuf ou de fruits, ou de combinaisons de ces constituants, rend la méthode de Röse-Gottlieb inadaptée. Dans le cas de ces produits, une méthode utilisant le principe de Weibull-Berntrop est adaptée, par exemple l’ISO 8262-2|FIL 124-2; — pour h), les produits qui ne se dissolvent pas complètement dans l’hydroxyde d’ammonium en raison de la présence d’amidon ou de dextrine à des fractions massiques supérieures à 5 % (en matière sèche), ou de la présence de grumeaux. Dans le cas de ces produits, une méthode utilisant le principe de Weibull-Berntrop est adaptée, par exemple l’ISO 8262-1|FIL 124-1.
General Information
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 23318
IDF 249
First edition
2022-11
Milk, dried milk products and
cream — Determination of fat content
— Gravimetric method
Lait, produits laitiers secs et crème — Détermination de la teneur en
matière grasse — Méthode gravimétrique
Reference numbers
IDF 249:2022(E)
IDF 249:2022(E)
© ISO and IDF 2022
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Published in Switzerland
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IDF 249:2022(E)
Contents Page
Foreword .v
1 S c op e . 1
2 Nor m at i ve r ef er enc e s . 2
3 Terms and definitions . 2
4 P r i nc iple . 2
5 R e a g ent s . 2
6 A pp a r at u s . 3
7 S a mpl i n g . 4
8 P reparation of test sample . 5
8 .1 M i lk . 5
8.2 D ried milk products . 5
8 . 3 E v ap or at e d m i l k . 5
8.4 Sweetened condensed milk . 5
8.5 W hey cheese . 6
8.6 Cream . 6
8.7 S kimmed milk, whey and buttermilk . 6
8.8 M ilk-based infant foods . 6
8.8.1 Liquid products . 6
8.8.2 Viscous or pasty products . 7
8.9 M ilk-based edible ices and ice mixes . 7
8.9.1 E dible ices, ice mixes and concentrated ice mixes . 7
8.9.2 D ried ice mixes . 7
9 P r o c e du re .7
9.1 Te s t p or t ion . 7
9.2 B lank tests . 8
9.3 P reparation of fat-collecting vessel. 8
9.4 D e t er m i n at ion . 9
9.4.1 Preparation steps . 9
9.4 . 2 D e t er m i n at ion . 10
10 C alculation and expression of results .13
10 .1 C a lc u l at ion . 13
10.2 E xpression of results . .13
11 P r e c i s ion .14
11.1 I nterlaboratory test . . 14
11.2 R epeatability . 14
11.3 Reproducibility . 14
12 Te s t r ep or t .15
Annex A (informative) Additional procedures .16
Annex B (informative) Fat-extraction tube model with siphon or wash-bottle fittings .18
Annex C (informative) Interlaboratory study on raw milk .19
Annex D (informative) Interlaboratory study on raw sheep milk and raw goat milk .21
Annex E (informative) Interlaboratory study on dried milk products .22
Annex F (informative) Interlaboratory study on cream .23
Annex G (informative) Interlaboratory study on skimmed milk (specific method when high
accuracy is required, see 9.1) .24
Annex H (informative) Interlaboratory study on other dairy products .25
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IDF 249:2022(E)
Bibliography .27
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IDF 249:2022(E)
Foreword
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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). It is being published jointly by ISO
and IDF.
Any feedback or questions on this document should be directed to the user’s national standards body. A
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IDF 249:2022(E)
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 drawn to the possibility that some of the elements of this document may be the subject of
patent rights. 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 www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
This document was prepared by the IDF Standing Committee on Analytical Methods for Composition and
ISO Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products. It is
being published jointly by ISO and IDF.
The work was carried out by the ISO/IDF Action Team on C32 of the Standing Committee on Analytical
Methods for Composition under the aegis of its project leader, Mr P. Trossat (FR).
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