1、BS EN ISO7208:2008ICS 67.100.10NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDSkimmed milk, wheyand buttermilk Determination of fatcontent Gravimetricmethod (Referencemethod)(ISO 7208:2008)Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 18/05/2009 08:08,
2、 Uncontrolled Copy, (c) BSIThis British Standard was published under theauthority of the StandardsPolicy and StrategyCommittee on 31 January2009 BSI 2009ISBN 978 0 580 63538 0Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 7208:2008National forewordThis British Standard is the U
3、K implementation of EN ISO 7208:2008. Itsupersedes BS EN ISO 7208:2000 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee AW/5, Chemical analysis of milk and milk products.A list of organizations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 i
4、ts secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 18/05/2009 08:
5、08, Uncontrolled Copy, (c) BSIEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 7208October 2008ICS 67.100.10 Supersedes EN ISO 7208:1999 English VersionSkimmed milk, whey and buttermilk - Determination of fatcontent - Gravimetric method (Reference method)(ISO7208:2008)Lait crm, srum et babeurre
6、 - Dtermination de lateneur en matire grasse - Mthode gravimtrique(Mthode de rfrence) (ISO 7208:2008)Magermilch, Molke und Buttermilch - Bestimmung desFettgehaltes - Gravimetrisches Verfahren(Referenzverfahren) (ISO 7208:2008)This European Standard was approved by CEN on 14 October 2008.CEN members
7、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 lists and bibliographical references concerning such nationalstandards may be obtained on application to
8、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 responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same
9、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, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania
10、, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldw
11、ide for CEN national Members.Ref. No. EN ISO 7208:2008: ELicensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 18/05/2009 08:08, Uncontrolled Copy, (c) BSIBS EN ISO 7208:2008EN ISO 7208:2008 (E) 3 Foreword This document (EN ISO 7208:2008) has been prepared by Technical Committee ISO/TC 34 “Agricult
12、ural 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 endo
13、rsement, 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 identify
14、ing any or all such patent rights. This document supersedes EN ISO 7208:1999. 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, Denmark,
15、 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 7208:2008 has been approved by
16、 CEN as an EN ISO 7208:2008 without any modification. Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 18/05/2009 08:08, Uncontrolled Copy, (c) BSIBS EN ISO 7208:2008ISO 7208:2008(E) IDF 22:2008(E) ISO and IDF 2008 All rights reserved iiiContents Page Foreword iv Foreword. v 1 Scope 1 2 Normat
17、ive references 1 3 Terms and definitions .1 4 Principle2 5 Reagents.2 6 Apparatus .2 7 Sampling.3 8 Preparation of test sample4 9 Procedure .4 9.1 Test portion 4 9.2 Blank tests4 9.3 Preparation of fat-collecting vessel.5 9.4 Determination.5 10 Calculation and expression of results.7 10.1 Calculatio
18、n7 10.2 Expression of results 7 11 Precision.8 11.1 Interlaboratory test 8 11.2 Repeatability.8 11.3 Reproducibility.8 12 Test report 8 Annex A (informative) Notes on procedures 9 Annex B (informative) Alternative procedure using fat-extraction tubes with siphon or wash-bottle fittings .11 Bibliogra
19、phy 14 Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 18/05/2009 08:08, Uncontrolled Copy, (c) BSIBS EN ISO 7208:2008ISO 7208:2008(E) IDF 22:2008(E) iv ISO and IDF 2008 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national
20、standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO 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
21、 organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules g
22、iven in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. 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 leas
23、t 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 7208IDF 22 was prepared by Technical Committee ISO/TC
24、 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. This third edition of ISO 7208IDF 22 cancels and replaces the second edition (ISO 7208:1999), of which it constitutes a minor revision. Licensed
25、Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 18/05/2009 08:08, Uncontrolled Copy, (c) BSIBS EN ISO 7208:2008ISO 7208:2008(E) IDF 22:2008(E) ISO and IDF 2008 All rights reserved vForeword IDF (the International Dairy Federation) is a non-profit organization representing the dairy sector worldwide. I
26、DF 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 represented at the IDF Standing Committees carrying out the technical work. IDF collaborates wi
27、th 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 Committees for voting. Publication as an International Standard requires approval by at
28、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 identifying any or all such patent rights. ISO 7208IDF 22 was prepared by the Internat
29、ional 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-IDF Action Team Fat of the Standing Committee on Main components in milk under the aegis o
30、f its project leader, Mr G.J. Beutick (NL). This edition of ISO 7208IDF 22 cancels and replaces IDF 22:1987, of which it constitutes a minor revision. Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 18/05/2009 08:08, Uncontrolled Copy, (c) BSIBS EN ISO 7208:2008Licensed Copy: Wang Bin, ISO/EX
31、CHANGE CHINA STANDARDS, 18/05/2009 08:08, Uncontrolled Copy, (c) BSIBS EN ISO 7208:2008INTERNATIONAL STANDARD ISO 7208:2008(E)IDF 22:2008(E) ISO and IDF 2008 All rights reserved 1Skimmed milk, whey and buttermilk Determination of fat content Gravimetric method (Reference method) WARNING The use of t
32、his International Standard may involve hazardous materials, operations and equipment. This International Standard does 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
33、and determine the applicability of regulatory limitations prior to use. 1 Scope This International Standard specifies the reference method for the determination of the fat content of liquid skimmed milk, whey and buttermilk. It is a particularly accurate gravimetric method especially for the purpose
34、 of establishing the operating efficiency of cream separators. This International Standard also specifies the reference method for establishing correction tables for procedures with skimmed milk butyrometers. NOTE When a high accuracy of determination is not required, the method specified in ISO 121
35、1IDF 12is suitable. 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 referenced document (including any amendments) applies. ISO 83
36、5, 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 cylinders 3 Terms and definitions For the purposes of
37、this document, the following terms and definitions apply. 3.1 fat content of skimmed milk, whey and buttermilk mass fraction of substances determined by the procedure specified in this International Standard NOTE The fat content is expressed as a percentage mass fraction. Licensed Copy: Wang Bin, IS
38、O/EXCHANGE CHINA STANDARDS, 18/05/2009 08:08, Uncontrolled Copy, (c) BSIBS EN ISO 7208:2008ISO 7208:2008(E) IDF 22:2008(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 remove
39、d by distillation or evaporation. The mass of the substances extracted is 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 pu
40、rity. The reagents shall leave no appreciable residue when the determination 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 concent
41、rated solution of known concentration may be used (see 9.4.2). 5.2 Ethanol (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 volumetr
42、ic flask (6.14). Make up to the mark with water. NOTE The use of this solution, which allows the interface between the solvent and aqueous layers to be seen more clearly, is optional (see 9.4.3). Other aqueous indicator solutions can be used provided that they do not affect the result of the determi
43、nation. 5.4 Diethyl ether (C2H5OC2H5), free from peroxides (see Clause A.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 sa
44、fety precautions for handling, use, and disposal. 5.5 Light petroleum, with 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 reco
45、mmended because of its higher purity and consistent quality. 5.6 Mixed solvent. 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
46、 comply with legislation relating to the hazards in using such solvents. 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. Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 18/05/2009 08:0
47、8, Uncontrolled Copy, (c) BSIBS EN ISO 7208:2008ISO 7208:2008(E) IDF 22:2008(E) ISO and IDF 2008 All rights reserved 36.2 Centrifuge, capable of holding the fat-extraction flasks or tubes (6.6) and capable of spinning at a rotational frequency of 500 min1to 600 min1to produce a radial acceleration o
48、f 80g to 90g at the outer end of the flasks or tubes. The use of the centrifuge is optional but recommended (see 9.4.6). 6.3 Distillation or evaporation apparatus, for distilling the solvents and ethanol from the boiling or conical flasks, or evaporating from beakers and dishes (see 9.4.13) at a tem
49、perature 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 throughout its working space. The oven shall be fitted with a suitable thermometer. 6.5 Water bath, capable of being maintained at a temperature of between 35 C and 40 C. 6.6 Mojonnier-type fat-extraction flasks, as specified in ISO 3889IDF 219. NOTE It is also possible to use fat-extraction tubes, with siphon or wash-bottle fittings, but th
