BS ISO 488-2008 Milk - Determination of fat content - Gerber butyrometers《牛奶 脂肪含量的测定 格伯(Gerber)乳脂计》.pdf

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1、BS ISO 488:2008ICS 67.100.10; 67.260NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDMilk Determinationof fat content GerberbutyrometersThis British Standardwas published underthe authority of theStandards Policy andStrategy Committee on 30September 2008 BSI 2008

2、ISBN 978 0 580 63451 2Amendments/corrigenda issued since publicationDate CommentsBS ISO 488:2008National forewordThis British Standard is the UK implementation of ISO 488:2008. Itsupersedes BS 696-1:1989 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee A

3、W/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. Users are responsible for its correct application.Compliance with

4、a British Standard cannot confer immunityfrom legal obligations.BS ISO 488:2008Reference numbersISO 488:2008(E)IDF 105:2008(E)ISO and IDF 2008INTERNATIONAL STANDARD ISO488IDF105Second edition2008-09-01Milk Determination of fat content Gerber butyrometers Lait Dtermination de la teneur en matire gras

5、se Butyromtres Gerber BS ISO 488:2008ISO 488:2008(E) IDF 105:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and install

6、ed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobes licensing policy. Neither the ISO Central Secretariat nor the IDF accepts any liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of

7、 the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies and IDF national committees. In the unlikely

8、event that a problem relating to it is found, please inform the ISO Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO and IDF 2008 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, el

9、ectronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO or IDF at the respective address below. ISO copyright office International Dairy Federation Case postale 56 CH-1211 Geneva 20 Diamant Building Boulevard Auguste Reyers 80 B-1030 Brussels Tel.

10、+ 41 22 749 01 11 Tel. + 32 2 733 98 88 Fax + 41 22 749 09 47 Fax + 32 2 733 04 13 E-mail copyrightiso.org E-mail infofil-idf.org Web www.iso.org Web www.fil-idf.org Published in Switzerland ii ISO and IDF 2008 All rights reservedBS ISO 488:2008ISO 488:2008(E) IDF 105:2008(E) ISO and IDF 2008 All ri

11、ghts reserved iiiContents Page Foreword iv Foreword. v 1 Scope 1 2 Normative references 1 3 Types of butyrometer 1 4 Construction.2 4.1 Material .2 4.2 Shape and dimensions2 4.3 Neck 2 4.4 Large bulb (see also Clause 6).2 4.5 Graduated tube 2 4.6 Small bulb (see also Clause 6) .3 5 Scale and graduat

12、ions 3 5.1 Length of scale.3 5.2 Position of scale 3 5.3 Basis of scale (see also Clause 6) .3 5.4 Graduation lines.3 5.5 Graduation scheme .4 5.6 Graduation numbers and percentage symbol 4 5.7 Scale error tolerances (see also Clause 6) .4 6 Reference temperature4 7 Inscriptions.4 Annex A (informati

13、ve) Recommended stoppers 8 Annex B (informative) Recommended method for the determination of scale errors of butyrometers10 Bibliography 14 BS ISO 488:2008ISO 488:2008(E) IDF 105:2008(E) iv ISO and IDF 2008 All rights reservedForeword ISO (the International Organization for Standardization) is a wor

14、ldwide federation of national 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

15、 that committee. International 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

16、in accordance with the rules given 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 Standar

17、d 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 document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 488IDF 105 was prepared

18、 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. This second edition cancels and replaces the first edition (ISO 488:1983), of which it constitutes a minor revision

19、. BS ISO 488:2008ISO 488:2008(E) IDF 105:2008(E) ISO and IDF 2008 All rights reserved vForeword IDF (the International Dairy Federation) is a non-profit organization representing the dairy sector worldwide. IDF membership comprises National Committees in every member country as well as regional dair

20、y associations having signed a formal agreement on cooperation with IDF. All members of IDF have the right to be represented on 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 pro

21、ducts. 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 least 50 % of the IDF National Committees casting a vote. Attention is drawn to the possibil

22、ity 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 488IDF 105 was prepared by the International Dairy Federation (IDF) and Technical Committee ISO/TC 34, Food products, Subcommittee

23、SC 5, Milk and milk products. It is being published jointly by IDF and ISO. All work was carried out by the former Joint ISO/IDF/AOAC Group of Experts E40-E301 which is now part of the Joint ISO-IDF Action Team on Fat of the Standing Committee on Main components in milk. ISO 488IDF 105:2008 cancels

24、and replaces IDF 105:1981, of which it constitutes a minor revision. BS ISO 488:2008BS ISO 488:2008INTERNATIONAL STANDARD ISO 488:2008(E)IDF 105:2008(E) ISO and IDF 2008 All rights reserved 1Milk Determination of fat content Gerber butyrometers 1 Scope This International Standard specifies the chara

25、cteristics of seven types of butyrometer for use in the determination of the fat content of whole milk, partly skimmed milk and skimmed milk by the Gerber method specified in ISO 2446. Recommended stoppers for the butyrometers are described in Annex A and a recommended method of determining the scal

26、e errors of the butyrometers is described in Annex B. 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 (includi

27、ng any amendments) applies. ISO 2446, Milk Determination of fat content (Routine method) 3 Types of butyrometer Seven types of butyrometer are specified, as follows: a) a butyrometer with a scale range of 0 % to 0,5 % fat, the smallest scale division of which is 0,02 %; this is a “double-quantity” b

28、utyrometer suitable for skimmed milk; b) a butyrometer with a scale range of 0 % to 4 % fat, the smallest scale division of which is 0,05 %; this is a “precision” butyrometer suitable for whole milk of standardized fat content and partly skimmed milk; c) butyrometers with scale ranges of 0 % to 5 %,

29、 0 % to 6 %, 0 % to 7 % and 0 % to 8 % fat, respectively, the smallest scale divisions of which are 0,1 %; these are “general-purpose” butyrometers suitable for whole milk; d) a butyrometer with a scale range of 0 % to 10 % fat, the smallest scale division of which is 0,2 %; this is suitable for who

30、le milk of high fat content, for example sheeps milk. NOTE 1 The 0 % to 0,5 % and 0 % to 4 % butyrometers are also suitable for whey and buttermilk, but this usage is not yet described in ISO 2446. NOTE 2 For the meaning of “% fat” in relation to scale range, see ISO 2446. BS ISO 488:2008ISO 488:200

31、8(E) IDF 105:2008(E) 2 ISO and IDF 2008 All rights reserved4 Construction 4.1 Material The butyrometers shall be made of clear glass which is as free as possible from visible defects. The stress in the glass shall be reduced by annealing to minimize the possibility of fracture by thermal or mechanic

32、al shock. The glass shall be resistant to the reagents used in the Gerber method (see ISO 2446). 4.2 Shape and dimensions The shape and dimensions of the butyrometers shall be as shown in Figures 1, 2, 3 and 4; the 0 % to 5 %, 0 % to 7 % and 0 % to 8 % butyrometers shall have the same shape and dime

33、nsions as the 0 % to 6 % butyrometer shown in Figure 3. The internal surface of the butyrometers shall be smooth and free from any defects so that, in use, none of the fat is prevented from entering the graduated tube. The outer surface of the butyrometers shall be symmetrical about the axis and cha

34、nges in cross-section shall be smooth, particularly the transition from the large bulb to the graduated tube. The minimum wall thickness at any point shall be 0,9 mm in order to ensure that the butyrometers are sufficiently robust for the usage to which they are normally subjected. 4.3 Neck Two type

35、s of neck are permitted: a) Plain-neck, strengthened at the outer end by an outside rim not exceeding 2,5 mm in thickness (see Figures 1 and 3); b) Corrugated neck, with the corrugations at right angles to the axis of the butyrometer and not in the form of a spiral producing a screw thread (see Figu

36、res 2 and 4). The number of corrugations is not specified. The internal diameter of a corrugated neck shall be measured at the crests of the corrugations. 4.4 Large bulb (see also Clause 6) The capacity of the large bulb, measured between the end of the neck and the 0 % graduation line (i.e. between

37、 levels A and B in Figures 1, 2, 3 and 4), shall be in accordance with Table 1 for the different types of butyrometer. Table 1 Capacity of large bulb according to type of butyrometer Scale range % fat Capacity of large bulb ml 0 to 0,5 43,5 0,5 0 to 4 21,7 0,3 0 to 5, 6, 7 or 8 21,5 0,4 0 to 10 21,0

38、 0,4 4.5 Graduated tube The graduated tube shall be of the flat-bore type shown in cross-section in Figures 1, 2, 3 and 4. BS ISO 488:2008ISO 488:2008(E) IDF 105:2008(E) ISO and IDF 2008 All rights reserved 34.6 Small bulb (see also Clause 6) The capacity of the small bulb, measured between the top

39、graduation line and the inside of the end of the bulb (i.e. between levels C and D in Figures 1, 2, 3 and 4), shall be at least 1,5 ml for all the butyrometers. The small bulb shall be slightly tapered as shown in Figures 1, 2, 3 and 4, and the inside of the bulb shall be so shaped that liquid can f

40、low freely between the bulb and the graduated tube. A small patch of matt surface, on which a temporary identification mark can be written, shall be provided on the small bulb. 5 Scale and graduations 5.1 Length of scale The length of the scale between the extreme graduation lines (i.e. between leve

41、ls B and C in Figures 1, 2, 3 and 4) shall be as follows: a) 0 % to 0,5 % butyrometer: not less than 17,5 mm; b) all other butyrometers: not less than 65 mm. It is recommended that scale lengths are as large as possible, consistent with the other constructional requirements, for ease of reading the

42、scales. 5.2 Position of scale The position of the scale on the flat-bore tube shall be such that the scale is approximately central with respect to the length of the tube and that the tube is internally uniform in cross-section for at least 3 mm beyond each end of the scale. 5.3 Basis of scale (see

43、also Clause 6) The basis of the scale shall be as follows: a) for the 0 % to 0,5 % butyrometer, the capacity of the flat-bore tube between the 0 % and 0,5 % graduation lines shall be 0,125 ml; b) for all other butyrometers, the capacity of the flat-bore tube between any two graduation lines covering

44、 a range of 1 % shall be 0,125 ml. 5.4 Graduation lines The graduation lines shall be fine, clean and permanent, and of a uniform thickness which is not less than 0,1 mm and not more than 0,2 mm. The lines shall lie in planes perpendicular to the longitudinal axis of the flat-bore tube, with no evid

45、ent irregularity in their spacing. The mid-points of the lines shall be coincident with the longitudinal axis. Short graduation lines shall be at least 2 mm in length for the 0 % to 0,5 % and 0 % to 4 % butyrometers, and at least 3 mm in length for all other butyrometers. Graduation lines of interme

46、diate length shall project equally to the left and right for a distance of at least 1 mm beyond the short graduation lines. Full-length graduation lines shall extend completely across the flat portion of the front of the flat-bore tube. BS ISO 488:2008ISO 488:2008(E) IDF 105:2008(E) 4 ISO and IDF 20

47、08 All rights reserved5.5 Graduation scheme The graduation scheme shall be as follows: a) for the 0 % to 0,5 % butyrometer: the graduation lines shall indicate 0,02 % intervals, those indicating 0,1 % intervals being full length and numbered and the remainder being short (see Figure 1); b) for the 0

48、 % to 4 % butyrometer: the graduation lines shall indicate 0,05 % intervals, those indicating 1 % intervals being full length and numbered, those indicating 0,5 % intervals being full length, those indicating 0,1 % intervals being of intermediate length and the remainder being short (see Figure 2);

49、c) for the 0 % to 5 %, 0 % to 6 %, 0 % to 7 % and 0 % to 8 % butyrometers: the graduation lines shall indicate 0,1 % intervals, those indicating 1 % intervals being full length and numbered, those indicating 0,5 % intervals being of intermediate length and the remainder being short (see Figure 3); d) for the 0 % to 10 % butyrometer: the graduation lines shall indicate 0,2 % intervals, those indicating 1 % intervals being full length and numbered and the remainder being short (see Figure 4). 5.6 Graduation numbers