ISO INTERNATIONAL STANDARD 26462 IDF 214 First edition 2010-06-15 Milk Determination of lactose content Enzymatic method using difference in pH Lait - Détermination de la teneur en lactose - Methode enzymatique par pH-metrie differentielle Reference numbers ISO 26462:2010(E) IDF214:2010(E) @ ISO and IDF 2010 py IHS under lic itted without license from IHS Not for Resale ISO 26462:2010(E) IDF 214:2010(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 a trademark of Adobe Systems 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 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. COPYRIGHT PROTECTED DOCUMENT @ ISO and IDF 2010 All rights reserved. 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 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 Copyrgh Interatinal Oorganization for Standardization @ISOand IDF2010-All rights reserved vided by IHS under Not for Resale ISO 26462:2010(E) IDF214:2010(E) Contents Page Foreword. iv Foreword 1 Scope 2 Terms and definitions 3 Principle 4 Reagents 5 6 Sampling 7 Preparation of test sample .. 8 Procedure 8.1 General 8.2 Blank determination . 8.3 Calibration. 8.4 Checking the calibration. 8.5 Determination .... 8.6 Checking the stability . 8.7 Cleaning procedure.... 9 Maintenanceoftheelectrodes.. 9.1 Regeneration.. 9.2 Strong regeneration 10 Calculation and expression of results 10.1 Calculation 10.2 Expressionofresults 11 Precision .... 11.1 Interlaboratory test 11.2 Repeatability 11.3 Reproducibility 12 Test report. Annex A (informative) Basic diagram of a differential pH apparatus Annex B (informative) Collaborative trial , Annex C (informative) Comparison between the pH and HPLC methods 10 Bibliography. Copyright International Organization for Standardization*0 - All rights reserved ili cense from IHS Not for Resale