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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN ISO 1854:2000 The E
2、uropean Standard EN ISO 1854:1999 has the status of a British Standard ICS 67.100.30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Whey cheese Determination of fat content Gravimetric method (Reference method) Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 14:53:28 G
3、MT+00:00 2006, Uncontrolled Copy, (c) BSI This British Standard, having been prepared under the direction of the Consumer Products and Services Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 January 2000 BSI 01-2000 ISBN 0 580 35105 X BS EN
4、 ISO 1854:2000 Amendments issued since publication Amd. No.DateComments National foreword This British Standard is the English language version of EN ISO 1854:1999. It is identical with ISO 1854:1999. The UK participation in its preparation was entrusted to Technical Committee AW/5, Chemical analysi
5、s of milk and milk products, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European
6、 developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references Attention is drawn to the fact that CEN and CENELEC Standards normally include an annex which lists normative references to international p
7、ublications with their corresponding European publications. The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled International Standards Correspondence Index, or by using the F
8、ind facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from lega
9、l obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN ISO title page, the EN ISO foreword page, the ISO title page, pages ii and iii, a blank page, pages 1 to 14, an inside back cover and a back cover. The BSI copyright notice displayed in this document
10、 indicates when the document was last issued. Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 14:53:28 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 14:53:28 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 1854:1999 Licensed Copy: sheffiel
11、dun sheffieldun, na, Sun Nov 19 14:53:28 GMT+00:00 2006, Uncontrolled Copy, (c) BSI A Reference number ISO 1854:1999(E) INTERNATIONAL STANDARD ISO 1854 Third edition 1999-10-01 Whey cheese Determination of fat content Gravimetric method (Reference method) Fromage de srum Dtermination de la teneur en
12、 matire grasse Mthode gravimtrique (Mthode de rfrence) EN ISO 1854:1999 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 14:53:28 GMT+00:00 2006, Uncontrolled Copy, (c) BSI )E(9991:4581 OSI ii Contents 1 Scope1 2 Normative reference1 3 Term and definition .1 4 Principle1 5 Reagents.2 6 Apparat
13、us.2 7 Sampling.3 8 Preparation of test sample3 9 Procedure.4 9.1 Test portion.4 9.2 Blank tests.4 9.3 Preparation of fat-collecting vessel4 9.4 Determination5 10 Calculation and expression of results.7 10.1 Calculation.7 10.2 Expression of results .7 11 Precision.7 11.1 Interlaboratory test.7 11.2
14、Repeatability7 11.3 Reproducibility8 12 Test report8 Annex A (informative) Notes on procedures9 Annex B (informative) Alternative procedure using fat-extraction tubes with siphon or wash-bottle fittings 11 Bibliography14 EN ISO 1854:1999 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 14:53:2
15、8 GMT+00:00 2006, Uncontrolled Copy, (c) BSI OSI)E(9991:4581 OSI iii Foreword 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 ISO technic
16、al 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 closely wi
17、th 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 3. Draft International Standards adopted by the technical committees are circulated to the
18、 member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 1854 was prepared by Technical Committee ISO/TC 34, Agricultural food products, Subcommittee SC 5, Milk and milk products, in collabo
19、ration with the International Dairy Federation (IDF) and AOAC International, and will also be published by these organizations. This third edition cancels and replaces the second edition (ISO 1854:1987), which has been technically revised. Annexes A and B of this International Standard are for infor
20、mation only. EN ISO 1854:1999 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 14:53:28 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 1854:1999 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 14:53:28 GMT+00:00 2006, Uncontrolled Copy, (c) BSI INTERNATIONAL STANDARD ISOISO 1854:1999
21、(E) 1 Whey cheese Determination of fat content Gravimetric method (Reference method) WARNING: The use of this International Standard may involve hazardous materials, operations and equipment. This standard does not purport to address all the safety problems associated with its use. It is the respons
22、ibility of the user of this standard to establish safety and health practices and determine the applicability of regulatory limitations prior to use. 1 Scope This International Standard specifies the reference method for the determination of fat content of whey cheese. NOTE If the whey cheese does n
23、ot dissolve completely in the ammonia or if it contains free fatty acids in significant quantities (only in exceptional cases and then noticeable by a distinct smell), the result of the determination will be too low. With such products recourse should be made to a method utilizing the Weibull-Berntr
24、op principle (see ISO 8262-3). 2 Normative reference The following normative document contains provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, this publications do not apply. Howe
25、ver, parties to agreement based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
26、 maintain registers of currently valid International Standards. ISO 3889, Milk and milk products Determination of fat content Mojonnier-type fat extraction flasks. 3 Term and definition For the purposes of this International Standard, the following term and definition apply. 3.1 fat content of whey
27、cheese mass fraction of substances determined by the procedure specified in this International Standard. NOTE The fat content is expressed as a mass fraction, in percent formerly given as % (m/m). 4 Principle An ammoniacal ethanolic solution of a test portion is extracted with diethyl ether and ligh
28、t petroleum. The solvents are removed by distillation or evaporation. The mass of the substances extracted is determined. NOTE This is usually known as the Rse-Gottlieb principle. EN ISO 1854:1999 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 14:53:28 GMT+00:00 2006, Uncontrolled Copy, (c)
29、BSI )E(9991:4581 OSI OSI 2 5 Reagents Use only reagents of recognized analytical grade, unless otherwise specified, and distilled or demineralized water or water of equivalent purity. The reagents shall leave no appreciable residue when the determination is carried out by the method specified (see 9
30、.2.2). 5.1 Ammonia solution, containing a mass fraction of NH3 of 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 9.4.3). 5.2 Ethanol (C2H5OH), or ethanol denatured by methanol, c
31、ontaining a volume fraction of ethanol of at least 94 %. (See A.5.) 5.3 Congo red solution Dissolve 1 g of Congo red in water in a 100 ml one-mark volumetric flask (6.14). Dilute to the mark with water. NOTE The use of this solution, which allows the interface between the solvent and aqueous layers
32、to be seen more clearly, is optional (see 9.4.4). Other aqueous colour solutions may be used provided that they do not affect the result of the determination. 5.4 Diethyl ether (C2H5OC2H5), free from peroxides (see A.3), containing no more than 2 mg/kg of antioxidants, and complying with the require
33、ments for the blank test (see 9.2.2, A.1 and A.4). NOTE The use of diethyl ether could lead to hazardous situations. Due to expected changes in safety regulations studies are ongoing to replace diethyl ether by another reagent provided that it does not affect the end result of the determination. 5.5
34、 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, A.1 and A.4). NOTE The use of pentane is recommended because of its higher purity and constant qualit
35、y. 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 comply with legislation relating to the hazards in using
36、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. 6.2 Centrifuge, capable of holding the fat-extraction flasks or tubes (6.6) and capable of spinning at a rotational frequency of
37、 500 min1 to 600 min1 to produce a radial acceleration of 80 g to 90 g at the outer end of the flasks or tubes. NOTE The use of the centrifuge is optional but recommended (see 9.4.7). 6.3 Distillation or evaporation apparatus, for distilling the solvents and ethanol from the boiling or conical flask
38、s, 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 throughout its working space. EN ISO 1854:1999 Licensed Copy: sheffieldun
39、sheffieldun, na, Sun Nov 19 14:53:28 GMT+00:00 2006, Uncontrolled Copy, (c) BSI OSI)E(9991:4581 OSI 3 The oven shall be fitted with a suitable thermometer. 6.5 Water bath, capable of boiling water. 6.6 Mojonnier-type fat extraction flasks, as specified in ISO 3889. NOTE It is also possible to use fa
40、t-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 bark corks or stoppers of other material e.g. silicone rubber or polytetrafluoroethylene (PTFE) u
41、naffected by the reagents used. Bark corks 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 the water so that they are saturated when used. 6.7 Rack, for holding the fat-extraction flasks (or tub
42、es) (6.6). 6.8 Wash bottle, suitable for use with the mixed solvent (5.6). A plastics wash bottle shall not be used. 6.9 Fat-collecting vessels, such as boiling flasks (flat-bottomed), of capacities 125 ml to 250 ml, conical flasks, of capacity 250 ml, or metal dishes. If metal dishes are used, they
43、 shall be of stainless steel, flat-bottomed with a diameter of 80 mm to 100 mm and a height of approximately 50 mm. 6.10 Boiling aids, fat-free, of non-porous porcelain or silicon carbide (optional when metal dishes are used). 6.11 Measuring cylinders, of capacities 5 ml and 25 ml. 6.12 Pipettes, gr
44、aduated, of capacity 10 ml. 6.13 Tongs, made of metal, for holding flasks, beakers or dishes. 6.14 Appropriate grinding device. 6.15 Volumetric flasks, one-mark, of capacity 100 ml. 7 Sampling Sampling is not part of the method specified in this International Standard. A recommended sampling method
45、is given in ISO 707. It is important that the laboratory receive a sample which is truly representative and has not been damaged or changed during transport or storage. 8 Preparation of test sample Prepare the test sample using an appropriate device (6.14). Quickly mix the ground or grated mass and,
46、 if possible, grind it a second time. Again mix thoroughly. Clean the device after preparing each test sample. If the test sample cannot be ground or grated, mix it thoroughly by intensive kneading, for example with a pestle in a mortar. The danger of moisture loss during grinding or grating of the
47、sample should be avoided as far as practically possible. EN ISO 1854:1999 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 19 14:53:28 GMT+00:00 2006, Uncontrolled Copy, (c) BSI )E(9991:4581 OSI OSI 4 Keep the prepared test sample in an airtight sample container until the time of analysis, which
48、should be carried out on the same day. If delay is unavoidable, take every precaution to ensure proper storage of the test sample. When refrigerated, ensure that any condensation of moisture on the inside surface of the container is thoroughly and uniformly reincorporated into the test sample. 9 Pro
49、cedure NOTE 1 If it is required to check whether the repeatability limit (11.2) is met, carry out two single determinations in accordance with 9.1 to 9.4 NOTE 2 An alternative procedure using fat-extraction tubes with siphon or wash-bottle fittings (see note in 6.6) is given in annex B. 9.1 Test portion Mix the test sample (clause 8) by gently stirring or rotating and inverting the sample container several times. Immediately weigh to the nearest 1 mg, about 3 g of the prepared test sample, directly or by