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1、 Reference numbers ISO 5537:2004(E) IDF 26:2004(E) ISO and IDF 2004 INTERNATIONAL STANDARD ISO 5537 IDF 26 First edition 2004-06-01 Dried milk Determination of moisture content (Reference method) Lait sec Dtermination du taux dhumidit (Mthode de rfrence) Copyright International Organization for Stan
2、dardization Provided by IHS under license with ISO Licensee=Aramco HQ/9980755100 Not for Resale, 04/23/2007 03:16:33 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 5537:2004(E) IDF 26:2004(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance wi
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5、zed 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 event that a problem relating to it is found, please inform the ISO Central Secretariat at the address given below. ISO and IDF 2004 All rights re
6、served. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO or IDF at the respective address below. ISO copyright office Intern
7、ational Dairy Federation Case postale 56 CH-1211 Geneva 20 Diamant Building Boulevard Auguste Reyers 80 B-1030 Brussels Tel. + 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
8、 in Switzerland ii ISO and IDF 2004 All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Aramco HQ/9980755100 Not for Resale, 04/23/2007 03:16:33 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 5537
9、:2004(E) IDF 26:2004(E) ISO and IDF 2004 All rights reserved 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 technical c
10、ommittees. 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 with t
11、he 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. Draft Internat
12、ional 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 document may be
13、 the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 5537IDF 26 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products, and the International Dairy Federation (IDF), in collaboration with
14、AOAC International. It is being published jointly by ISO and IDF and separately by AOAC International. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Aramco HQ/9980755100 Not for Resale, 04/23/2007 03:16:33 MDTNo reproduction or networking pe
15、rmitted without license from IHS -,-,- ISO 5537:2004(E) IDF 26:2004(E) iv ISO and IDF 2004 All rights reserved Foreword IDF (the International Dairy Federation) is a worldwide federation of the dairy sector with a National Committee in every member country. Every National Committee has the right to
16、be represented on the IDF Standing Committees carrying out the technical work. IDF collaborates with ISO and AOAC International 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 Committee
17、s are circulated to the National Committees for voting. Publication as an International Standard requires approval by at least 50 % of the National Committees casting a vote. ISO 5537IDF 26 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products, and t
18、he International Dairy Federation (IDF), in collaboration with AOAC International. It is being published jointly by ISO and IDF and separately by AOAC International. All work was carried out by the Joint ISO/IDF/AOAC Action Team Action Team, Water, of the Standing Committee, Main components in milk,
19、 under the aegis of its project leader, Mr G.J. Beutick (NL) and Mr R.J. de Knegt (NL). This first edition of ISO 5537IDF 26 cancels and replaces the first edition of IDF 26A:1993, which has been technically revised. Copyright International Organization for Standardization Provided by IHS under lice
20、nse with ISO Licensee=Aramco HQ/9980755100 Not for Resale, 04/23/2007 03:16:33 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 5537:2004(E) IDF 26:2004(E) ISO and IDF 2004 All rights reserved 1 Dried milk Determination of moisture content (Referen
21、ce method) WARNING The use of ISO 5537 IDF 26 may involve the use of hazardous materials, operations, and equipment. This standard does not purport to address all the safety risks associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and healt
22、h practices and determine the applicability of local regulatory limitations prior to use. 1 Scope This International Standard specifies a method for the determination of the moisture content of all types of dried milk. 2 Terms and definitions For the purposes of this document, the following terms an
23、d definitions apply. 3.1 moisture content mass fraction of substances determined by the procedure specified in this International Standard NOTE The moisture content is expressed as a percentage by mass. 3 Principle A test portion is dried in a drying oven set at 87 C for 5 h while dry air is passed
24、through the test portion. The loss of mass of the test portion (which is related to the content of “non-chemically bound” water) is determined. 4 Apparatus Usual laboratory apparatus and, in particular, the following. 4.1 Analytical balance, capable of weighing to the nearest 1 mg, with a readabilit
25、y of 0,1 mg. 4.2 Drying oven, capable of being maintained at 87 C 1 C throughout the working space, with forced ventilation, thermostatically controlled, with the following equipment (see also Figure A.1). 4.2.1 Metal block, provided with channels of diameter 4,3 mm for holding the columns (4.4) in
26、the drying oven. 4.2.2 Copper tubes, of length 1 500 mm, of internal diameter 2 mm, connected to the metal block in the drying oven. 4.2.3 Constant pressure regulator, provided with restrictors, capable of delivering 33 ml/min of dry air to each column in the drying oven. Copyright International Org
27、anization for Standardization Provided by IHS under license with ISO Licensee=Aramco HQ/9980755100 Not for Resale, 04/23/2007 03:16:33 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 5537:2004(E) IDF 26:2004(E) 2 ISO and IDF 2004 All rights reserved 4.2.4 Tube, made of
28、polycarbonate, of length 350 mm, of diameter 40 mm, filled with silica gel with hygrometric indicator. The silica gel should have been dried at 150 C for more than 12 h before use. Using the dry compressed air (4.11), no colour change of the hygrometric indicator should be noticed. 4.3 Desiccator, c
29、ontaining freshly dried silica gel with hygrometric indicator. 4.4 Columns, made of hard polypropylene (Phenomenex 121310211)1), of length 90 mm, of internal diameter 20 mm, provided with two polyethene filters (Phenomenex 12121023)1), narrowed towards one end to fit onto the block (4.2.1). 4.5 Synt
30、hetic stoppers, made of soft polyethylene (Emergo 20273 B198 and 20371 U1)1). 4.6 Container, suitable for holding the columns (4.4). 4.7 Container, suitable for holding the synthetic stoppers (4.5). 4.8 Rod, made of polyvinyl chloride (PVC), of length 120 mm, of diameter 18 mm, suitable for placing
31、the polyethylene filters in the column (4.4). 4.9 Tweezers, suitable for removing the polyethylene filters from the column (4.4). 4.10 Soap-film meter, suitable for measuring a flow of 33 ml/min. 4.11 Dry compressed air, minimum pressure of 200 kPa, moisture content of u 0,01 mgH2O per litre at atmo
32、spheric pressure, free of any organic material. Use metal tubes only to connect the source of compressed air to the equipment in the drying oven (4.2). 4.12 Container, made of glass, provided with an airtight lid. NOTE The apparatus mentioned in 4.2 and those in 4.4 to 4.8 are available commercially
33、 (e.g. Elbanton and Funke Gerber)2). 5 Sampling It is important that the laboratory receive a sample which is truly representative and has not been damaged or changed during transport or storage. Sampling is not part of the method specified in this International Standard. A recommended sampling meth
34、od is given in ISO 707. 6 Preparation of test sample Transfer the whole test sample to a dry, hermetically closed container (4.12) of capacity approximately twice the volume of the sample. Mix intensively by rotating and shaking the container. Use a statistical sampling plan if there is evidence of
35、sample inhomogeneity even after the intensive mixing mentioned above. 1) Phenomenex and Emergo are examples of suitable products available commercially. 2) Elbanton and Funke Gerber are the trade names of products supplied by Elbanton b.v., Uitingstraat 18, 5331 EJ, Kerkdriel (NL) and Funke-Dr.N.Ger
36、ber Labortechnik GmbH, Ringstrasse 42, 12105, Berlin, respectively. The information in footnotes 1) and 2) is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO or IDF of the product named. Equivalent products may be used if they can be sh
37、own to lead to the same results. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Aramco HQ/9980755100 Not for Resale, 04/23/2007 03:16:33 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 5537:2004(E) IDF 26:2004(E)
38、 ISO and IDF 2004 All rights reserved 3 7 Procedure 7.1 Preparation of column 7.1.1 Set the constant pressure regulator at approximately 100 kPa. Measure, using the soap-film meter (4.10), the airflow of each channel. Calculate the average flow per channel. Adjust the pressure, if necessary, to obta
39、in an average airflow of 33 ml/min per channel. 7.1.2 Remove both synthetic stoppers from the column (4.4). Place the stoppers in the container (4.7) and store at room temperature. 7.1.3 Place the column, provided with filters placed in position as shown in Figure A.1, in the metal block (4.2.1) in
40、the oven (4.2) set at 87 C for at least 1 h. Use slight pressure when placing the column in position to create an airtight connection. 7.1.4 Take the column out of the oven and close it with the synthetic stoppers (see 7.1.2). Place the closed column in the container (4.6) with the other prepared co
41、lumns. Place the container and the columns in the desiccator (4.3). Close the desiccator and allow the whole to cool for 60 min 5 min. 7.2 Preparation of test portion 7.2.1 After cooling (see 7.1.4), take one closed column at a time out of the container while leaving the container in the desiccator.
42、 Close the desiccator immediately after taking out a column. Weigh the closed column to the nearest 1 mg, recording the mass to four decimal places. 7.2.2 Remove the synthetic stoppers from the pre-weighed column (see 7.2.1). Using tweezers (4.9), also remove the upper filter from the column. Keep t
43、he stoppers and the filter in a dry place in the weighing room. 7.2.3 Add 5,0 g 0,3 g of prepared test sample (Clause 6) to the column. Using the rod (4.8), place the upper filter back in position in the column. Remove any dried milk above the filter with a clean tissue. Close the column with both s
44、ynthetic stoppers (see 7.2.2). 7.2.4 Immediately weigh the closed column to the nearest 1 mg, recording the mass to four decimal places. Open the desiccator, place the closed column back into the container and close it again. 7.2.5 When the analysis involves more than one test sample, prepare all te
45、st portions by repeating the procedure from 7.2.1 to 7.2.4 for each separate test portion. Handle only one column at a time. 7.3 Determination 7.3.1 Open the desiccator. Take one closed column with the prepared test portion (see 7.2.4) at a time out of the container. Remove both synthetic stoppers f
46、rom each column. Place the stoppers in the container (4.7) and store at room temperature. 7.3.2 Place each column and its contents in the metal block (4.2.1) which is placed in the drying oven (4.2). As soon as ready, close the oven. Dry the columns and their contents in the oven (4.2) set at 87 C f
47、or 5 h. 7.3.3 After drying, remove each column from the metal block. Replace both synthetic stoppers. Open the desiccator and place the dried columns and their contents back into the container (4.6). Immediately close the desiccator after placing the last column into the container. Allow the whole t
48、o cool for 60 min 5 min. 7.3.4 After cooling (see 7.3.3), open the desiccator and, in case of more than one test sample, take one closed column at a time out of the container leaving the container in the desiccator. Close the desiccator immediately after taking out a column. Weigh the closed column to the nearest 1 mg, recording the mass to four decimal places. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Aramco HQ/9980755100 Not for Resale, 04/23/2007 03:16:33 MDTNo reproduction or networki