1、BS EN ISO8381:2008ICS 67.100.99; 67.230NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDMilk-based infantfoods Determinationof fat content Gravimetric method(Reference method)(ISO 8381:2008)This British Standardwas published under theauthority of the StandardsPol
2、icy and StrategyCommittee on 31 January2009 BSI 2009ISBN 978 0 580 63534 2Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 8381:2008National forewordThis British Standard is the UK implementation of EN ISO 8381:2008. Itsupersedes BS EN ISO 8381:2000 which is withdrawn.The UK part
3、icipation in its preparation was entrusted to TechnicalCommittee AW/5, Chemical analysis of milk and milk products.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract.
4、Users are responsible for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 8381October 2008ICS 67.230 Supersedes EN ISO 8381:2000 English VersionMilk-based infant foods - Determination of fat
5、 content -Gravimetric method (Reference method) (ISO 8381:2008)Aliments base de lait pour enfants en bas ge -Dtermination de la teneur en matire grasse - Mthodegravimtrique (Mthode de rfrence) (ISO 8381:2008)Suglingsnahrung auf Milchbasis - Bestimmung desFettgehaltes - Gravimetrisches Verfahren(Refe
6、renzverfahren) (ISO 8381:2008)This European Standard was approved by CEN on 14 October 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date l
7、ists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the resp
8、onsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Icel
9、and, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stas
10、sart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 8381:2008: EBS EN ISO 8381:2008EN ISO 8381:2008 (E) 3 Foreword This document (EN ISO 8381:2008) has been prepared by Technical Committee ISO/TC 34 “Agr
11、icultural food products“ in collaboration with Technical Committee CEN/TC 302 “Milk and milk products - Methods of sampling and analysis” the secretariat of which is held by NEN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by
12、 endorsement, at the latest by April 2009, and conflicting national standards shall be withdrawn at the latest by April 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for ide
13、ntifying any or all such patent rights. This document supersedes EN ISO 8381:2000. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Den
14、mark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 8381:2008 has been approv
15、ed by CEN as a EN ISO 8381:2008 without any modification. BS EN ISO 8381:2008ISO 8381:2008(E) IDF 123:2008(E) ISO and IDF 2008 All rights reserved iiiContents Page Foreword iv Foreword. v 1 Scope 1 2 Normative references 1 3 Terms and definitions .1 4 Principle2 5 Reagents.2 6 Apparatus .2 7 Samplin
16、g.3 8 Preparation of test sample4 8.1 Liquid products4 8.2 Viscous or pasty products4 8.3 Dried products .4 9 Procedure .4 9.1 Test portion 4 9.2 Blank tests5 9.3 Preparation of fat-collecting vessel.5 9.4 Determination.5 10 Calculation and expression of results.8 10.1 Calculation8 10.2 Expression o
17、f results 8 11 Precision.8 11.1 Interlaboratory test 8 11.2 Repeatability.8 11.3 Reproducibility.9 12 Test report 9 Annex A (informative) Notes on procedures 10 Annex B (informative) Alternative procedure using fat-extraction tubes with siphon or wash-bottle fittings .12 Bibliography 15 BS EN ISO 83
18、81:2008ISO 8381:2008(E) IDF 123:2008(E) iv ISO and IDF 2008 All rights reservedForeword 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 I
19、SO 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
20、closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards.
21、Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this d
22、ocument may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 8381IDF 123 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 b
23、eing published jointly by ISO and IDF. This third edition of ISO 8381IDF 123 cancels and replaces the second edition (ISO 8381:2000), of which it constitutes a minor revision. BS EN ISO 8381:2008ISO 8381:2008(E) IDF 123:2008(E) ISO and IDF 2008 All rights reserved vForeword IDF (the International Da
24、iry Federation) is a non-profit organization representing the dairy sector worldwide. IDF membership comprises National Committees in every member country as well as regional dairy associations having signed a formal agreement on cooperation with IDF. All members of IDF have the right to be represen
25、ted at the IDF Standing Committees carrying out the technical work. IDF collaborates with ISO in the development of standard methods of analysis and sampling for milk and milk products. Draft International Standards adopted by the Action Teams and Standing Committees are circulated to the National C
26、ommittees for voting. Publication as an International Standard requires approval by at least 50 % of the IDF National Committees casting a vote. 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
27、 identifying any or all such patent rights. ISO 8381IDF 123 was prepared by the International Dairy Federation (IDF) and Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products. It is being published jointly by IDF and ISO. All work was carried out by the Joint ISO-ID
28、F Action Team Fat of the Standing Committee on Main components in milk under the aegis of its project leader, Mr G.J. Beutick (NL). This edition of ISO 8381IDF 123 cancels and replaces IDF 123:1988, of which it constitutes a minor revision. BS EN ISO 8381:2008BS EN ISO 8381:2008INTERNATIONAL STANDAR
29、D ISO 8381:2008(E)IDF 123:2008(E) ISO and IDF 2008 All rights reserved 1Milk-based infant foods Determination of fat content Gravimetric method (Reference method) WARNING The use of this International Standard may involve hazardous materials, operations and equipment. This International Standard doe
30、s not purport to address all the safety problems associated with its use. It is the responsibility of the user of this International Standard to establish safety and health practices and determine the applicability of regulatory limitations prior to use. 1 Scope This International Standard specifies
31、 the reference method for the determination of the fat content of milk-based infant foods. The method is applicable to liquid, concentrated and dried milk-based infant foods with no, or not more than a mass fraction of 5 % (dry matter) of such added matter as starch, dextrin, vegetables, fruit, and
32、meat. NOTE 1 Malto-dextrins without higher molecular mass dextrins, which are often present in infant foods, do not disturb the Rse-Gottlieb extraction even when present in high concentrations. The method is not applicable to products which do not dissolve completely in ammonia owing to the presence
33、 of starch or dextrin at mass fractions of more than a few percent, or to the presence of hard lumps. The method is also not applicable to products which contain free fatty acids in significant quantities. The results obtained for these products are too low. NOTE 2 For such products, a method utiliz
34、ing the Weibull-Berntrop principle is suitable (see ISO 8262-1IDF 124-13). 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referen
35、ced document (including any amendments) applies. ISO 835, Laboratory glassware Graduated pipettes ISO 1042, Laboratory glassware One-mark volumetric flasks ISO 3889IDF 219, Milk and milk products Specification of Mojonnier-type fat extraction flasks ISO 4788, Laboratory glassware Graduated measuring
36、 cylinders 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 fat content of milk mass fraction of substances determined by the procedure specified in this International Standard NOTE The fat content is expressed as a percentage mass fraction. B
37、S EN ISO 8381:2008ISO 8381:2008(E) IDF 123:2008(E) 2 ISO and IDF 2008 All rights reserved4 Principle An ammoniacal ethanolic solution of a test portion is extracted with diethyl ether and light petroleum. The solvents are removed by distillation or evaporation. The mass of the substances extracted i
38、s determined. NOTE This is usually known as the Rse-Gottlieb principle. 5 Reagents Use only reagents of recognized analytical grade, unless otherwise specified, and only distilled or demineralized water or water of equivalent purity. The reagents shall leave no appreciable residue when the determina
39、tion is carried out by the method specified (see 9.2.2). 5.1 Ammonia solution, containing a mass fraction of NH3of approximately 25 % (20= 910 g/l). NOTE If ammonia solution of this concentration is not available, a more concentrated solution of known concentration may be used (see 9.4.2). 5.2 Ethan
40、ol (C2H5OH), or ethanol denatured by methanol, containing a volume fraction of ethanol of at least 94 %. (See Clause A.5.) 5.3 Congo red solution Dissolve 1 g of Congo red (C32H22N6Na2O6S2) in water in a 100 ml one-mark volumetric flask (6.14). Make up to the mark with water. NOTE The use of this so
41、lution, which allows the interface between the solvent and aqueous layers to be seen more clearly, is optional (see 9.4.4). Other aqueous indicator solutions can be used provided that they do not affect the result of the determination. 5.4 Diethyl ether (C2H5OC2H5), free from peroxides (see Clause A
42、.3), containing no more than 2 mg/kg of antioxidants, and complying with the requirements for the blank test (see 9.2.2, Clauses A.1 and A.4). WARNING The use of diethyl ether can lead to hazardous situations. Observe current safety precautions for handling, use, and disposal. 5.5 Light petroleum, w
43、ith any boiling range between 30 C and 60 C or, as equivalent, pentane (CH3CH23CH3) with a boiling point of 36 C and complying with the requirements for the blank test (see 9.2.2, Clauses A.1 and A.4). The use of pentane is recommended because of its higher purity and consistent quality. 5.6 Mixed s
44、olvent Shortly before use, mix equal volumes of diethyl ether (5.4) and light petroleum (5.5). 6 Apparatus WARNING Since the determination involves the use of volatile flammable solvents, all electrical apparatus employed shall comply with legislation relating to the hazards in using such solvents.
45、Usual laboratory equipment and, in particular, the following. 6.1 Analytical balance, capable of weighing to the nearest 1 mg, with a readability of 0,1 mg. BS EN ISO 8381:2008ISO 8381:2008(E) IDF 123:2008(E) ISO and IDF 2008 All rights reserved 36.2 Centrifuge, capable of holding the fat-extraction
46、 flasks or tubes (6.6) and capable of spinning at a rotational frequency of 500 min1to 600 min1to produce a radial acceleration of 80g to 90g at the outer end of the flasks or tubes. The use of the centrifuge is optional but recommended (see 9.4.7). 6.3 Distillation or evaporation apparatus, for dis
47、tilling the solvents and ethanol from the boiling or conical flasks, or evaporating from beakers and dishes (see 9.4.14) at a temperature not exceeding 100 C. 6.4 Drying oven, electrically heated, with ventilation port(s) fully open, capable of being maintained at a temperature of 102 C 2 C througho
48、ut its working space. The oven shall be fitted with a suitable thermometer. 6.5 Water baths, capable of being maintained at temperatures of between 30 C and 40 C, 40 C and 60 C, and 60 C and 70 C. 6.6 Mojonnier-type fat-extraction flasks, as specified in ISO 3889IDF 219. NOTE It is also possible to
49、use fat-extraction tubes, with siphon or wash-bottle fittings, but then the procedure is different. The alternative procedure is given in Annex B. The fat-extraction flasks shall be provided with good quality cork bungs or stoppers of other material (e.g. silicone rubber or polytetrafluoroethylene) unaffected by the reagents used. Cork bungs shall be extracted with the diethyl ether (5.4), kept in water at a temperature of 60 C or more for at least 15 min, and shall then be allowed to cool in th
