DIN EN ISO 1854-2009 Whey cheese - Determination of fat content - Gravimetric method (Reference method) (ISO 1854 2008) English version of DIN EN ISO 1854 2009-03《乳清干酪 脂肪含量的测定 重量法(.pdf

1、March 2009DEUTSCHE NORM English price group 12No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 67.100.30!$VV“1515197www

2、.din.deDDIN EN ISO 1854Whey cheese Determination of fat content Gravimetric method (Reference method) (ISO 1854:2008)English version of DIN EN ISO 1854:2009-03Molkenkse Bestimmung des Fettgehaltes Gravimetrisches Verfahren (Referenzverfahren) (ISO 1854:2008)Englische Fassung DIN EN ISO 1854:2009-03S

3、upersedesDIN EN ISO 1854:2000-04www.beuth.deDocument comprises 21 pagesDIN EN ISO 1854:2009-03 2 National foreword This standard has been prepared by Technical Committee ISO/TC 34 “Food products” (Secretariat: AFNOR, France), Subcommittee SC 5 “Milk and milk products” (Secretariat: NEN, Netherlands)

4、 in collaboration with Technical Committee CEN/TC 302 “Milk and milk products Methods of sampling and analysis” (Secretariat: NEN, Netherlands). The responsible German body involved in its preparation was the Normenausschuss Lebensmittel und landwirtschaftliche Produkte (Food and Agricultural Produc

5、ts Standards Committee), Technical Committee Milch und Milchprodukte Probenahme- und Untersuchungsverfahren. Based on the results of parallel voting, ISO 1854:2008 has been adopted as a European Standard. For reasons of environmental and worker protection, the German employers liability insurance as

6、sociations and inspectorates forbid the open evaporation of diethyl ether, which this standard allows as an alternative method. One way of reducing risks is to substitute diethyl ether with an equivalent amount of tert-butyl methyl ether (t-BME). This deviation from the specified procedure is to be

7、stated in the test report. The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 707 DIN EN ISO 707 ISO 835 DIN EN ISO 835 ISO 1042 DIN EN ISO 1042 ISO 4788 DIN EN ISO 4788 Amendments This standard differs from DIN EN ISO 1854:2000-04 as foll

8、ows: a) Clause 1 “Scope” has been rendered more precise. b) Clause 2 “Normative references” and clause 7 “Sampling” have been revised. c) The standard has been revised in form and substance and brought in line with the current rules of presentation. d) The bibliography has been updated. Previous edi

9、tions DIN EN ISO 1854: 2000-04 DIN EN ISO 1854:2009-03 3 National Annex NA (informative) Bibliography DIN EN ISO 707, Milk and milk products Guidance on sampling DIN EN ISO 835, Laboratory glassware Graduated pipettes DIN EN ISO 1042, Laboratory glassware One-mark volumetric flasks DIN EN ISO 4788,

10、Laboratory glassware Graduated measuring cylinders DIN EN ISO 1854:2009-03 4 This page is intentionally blank EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 1854October 2008ICS 67.100.30 Supersedes EN ISO 1854:1999 English VersionWhey cheese - Determination of fat content - Gravimetricmethod

11、(Reference method) (ISO 1854:2008)Fromage de srum - Dtermination de la teneur en matiregrasse - Mthode gravimtrique (Mthode de rfrence)(ISO 1854:2008)Molkenkse - Bestimmung des Fettgehaltes -Gravimetrisches Verfahren (Referenzverfahren) (ISO 1854:2008)This European Standard was approved by CEN on 14

12、 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 lists and bibliographical references concerning such nationalstandards may be o

13、btained 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 responsibility of a CEN member into its own language and notified to the CEN Manag

14、ement 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, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway

15、, Poland, Portugal,Romania, 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 b

16、y any means reservedworldwide for CEN national Members.Ref. No. EN ISO 1854:2008: EContents Page Foreword. 3 1 Scope 4 2 Normative reference 4 3 Terms and definitions .4 4 Principle5 5 Reagents.5 6 Apparatus .5 7 Sampling.6 8 Preparation of test sample7 9 Procedure .7 9.1 Test portion 7 9.2 Blank te

17、sts7 9.3 Preparation of fat-collecting vessel.8 9.4 Determination.8 10 Calculation and expression of results.10 10.1 Calculation10 10.2 Expression of results 11 11 Precision.11 11.1 Interlaboratory test 11 11.2 Repeatability.11 11.3 Reproducibility.11 12 Test report 11 Annex A (informative) Notes on

18、 procedures 12 Annex B (informative) Alternative procedure using fat-extraction tubes with siphon or wash-bottle fittings .14 Bibliography 17 2EN ISO 1854:2008 (E) DIN EN ISO 1854:2009-03 EN ISO 1854:2008 (E) Foreword This document (EN ISO 1854:2008) has been prepared by Technical Committee ISO/TC 3

19、4 “Agricultural 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

20、 or by 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 f

21、or identifying any or all such patent rights. This document supersedes EN ISO 1854:2008. 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 Republi

22、c, Denmark, 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 1854:2008 has been

23、approved by CEN as a EN ISO 1854:2008 without any modification. 3DIN EN ISO 1854:2009-03 WARNING The use of this 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.

24、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 the reference method for the determination of fat content of whey cheese.

25、 The method is not applicable to products which do not dissolve completely in ammonia solution or which contain free fatty acids in significant quantities. NOTE If the whey cheese does not dissolve completely in the ammonia or if it contains free fatty acids in significant quantities (only in except

26、ional cases and then noticeable by a distinct smell), the result of the determination will be too low. With such products, a method using the Weibull-Berntrop principle is suitable (see ISO 8262-3|IDF 124-33). 2 Normative reference The following referenced documents are indispensable for the applica

27、tion 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 835, Laboratory glassware Graduated pipettes ISO 1042, Laboratory glassware One-mark volumetric flasks ISO 3889ID

28、F 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 this document, the following terms and definitions apply. 3.1 fat content of whey cheese mass fraction of subst

29、ances determined by the procedure specified in this International Standard NOTE The fat content is expressed as a percentage mass fraction. 4EN ISO 1854:2008 (E) DIN EN ISO 1854:2009-03 4 Principle An ammoniacal ethanolic solution of a test portion is extracted with diethyl ether and light petroleum

30、. 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. 5 Reagents Use only reagents of recognized analytical grade, unless otherwise specified, and only distilled or demineralized water

31、or water of equivalent purity. 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

32、available, a more concentrated solution of known concentration may be used (see 9.4.3). 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

33、 100 ml one-mark volumetric 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 9.4.4). Other aqueous indicator solutions can be used provided that they do not affect

34、the result of the determination. 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 situa

35、tions. Observe current safety 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). T

36、he use of pentane is recommended 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

37、apparatus employed shall 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. 5EN ISO 1854:2008 (E) DIN EN ISO 1854:2009-03

38、6.2 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 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

39、). 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 9.4.14) at a temperature not exceeding 100 C. 6.4 Drying oven, electrically heated, with ventilation port(s) fully open, capable of be

40、ing 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 maintaining water at boiling point. 6.6 Mojonnier-type fat-extraction flasks, as specified in ISO 3889IDF 219. NOTE It is also possible to use f

41、at-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) unaff

42、ected 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 the water so that they are saturated when used. 6.7 Rack, for holding the fat-extraction flasks (or tubes)

43、(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 sha

44、ll 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, complying with the re

45、quirements of ISO 4788, class A, or any other apparatus suitable for the product concerned. 6.12 Pipettes, graduated, of capacity 10 ml, complying with the requirements of ISO 835, class A. 6.13 Tongs, made of metal, for holding flasks, beakers or dishes. 6.14 Appropriate grinding device. 6.15 Volum

46、etric flasks, one-mark, of capacity 100 ml, complying with the requirements of ISO 1042, class A. 7 Sampling A representative sample should have been sent to the laboratory. It should not have been damaged or changed during transport or storage. 6EN ISO 1854:2008 (E) DIN EN ISO 1854:2009-03 Sampling

47、 is not part of the method specified in this International Standard. A recommended sampling method is given in ISO 707IDF 501. 8 Preparation of test sample Prepare the test sample using an appropriate device (6.14). Quickly mix the ground or grated mass and, if possible, grind it a second time. Agai

48、n 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 sample should be avoided as far as practic

49、ally possible. Keep the prepared test sample in an airtight sample container until the time of analysis, which 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 Procedure NOTE 1 If it is required to check whether the repeatability limit (11.2) is met, carry out two sin