ISO INTERNATIONAL STANDARD 5548 IDF 106 Second edition 2004-12-01 Caseins and caseinates Determination of lactose content Photometric method Caséines et caseinates Détermination de la teneur en lactose - Methode photométrique Reference numbers ISO 5548:2004(E) Iso IDF 106:2004(E) @ISO and IDF 2004 ISO 5548:2004(E) IDF 106:2004(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. Neither the ISo Central Secretariat nor the IDF accepts any liability in this area. Adobe is atrademarkofAdobeSystems Incorporated. Details of 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 commitees. In the unlikely event that a problem relating to it is found, please inform the ISO Central Secretariat at the address given below. ISOandIDF2004 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, 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. + 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 [email protected] E-mail [email protected] Web www.iso.org Web www.fil-idf.org Published in Switzerland @ISO and IDF2004-All rights reserved ISO5548:2004(E) IDF106:2004(E) Contents Foreword. 1 Scope. 2 Normative references 3 Terms and definitions 4 Principle 5 Reagents 6 Apparatus 7 Sampling 8 8.1 Preparation of test sample.. 8.2 Preparation of a blank solution 8.3 Test portion ...... 8.4 Test solution.. 8.5 Determination. 8.6 Preparation of calibration graph 9 Calculation and expression of results . 9.1 9.2 Expressionof results 10 Precision 10.1 Repeatability 10.2 Reproducibility 11 Testreport Bibliography n24-All rights reserved ii ISO 5548:2004(E) IDF 106:2004(E) Foreword IsO(theInternationalOrganizationforStandardization)isaworldwidefederationofnationalstandards IsO technical committees. Each member body interested in a subject for which a technical committee has International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/lEC Directives, Part 2 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 the subject of patent rights. IsO shall not be held responsible for identifying any or all such patent rights. ISO 5548liDF 106 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, It is being published jointly by ISO and IDF and separately by AOAC International. This edition of ISO 5548liDF 106 cancels and replaces ISO 5548:1980, of which it constitutes a minor revision.Onlyeditorialchangeshavebeenmade. @ ISO and IDF 2004 - All rights reserved ISO 5548:2004(E) IDF 106:2004(E) Foreword IDF (the International Dairy Federation) is a worldwide federation of the dairy sector with a National Committeeineverymembercountry.EveryNationalCommitteehastherighttoberepresentedontheIDF 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