ISO INTERNATIONAL STANDARD 9231 IDF 139 First edition 2008-07-15 Milk and milk products Determination of the benzoic and sorbic acid contents Lait et produits laitiers - Détermination de la teneur en acide benzoique et en acide sorbique Reference numbers ISO 9231:2008(E) [SO IDF 139:2008(E) @ ISO and IDF 2008 ISO 9231:2008(E) IDF 139:2008(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 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 event that a problem relating to it is found, please inform the ISO Central Secretariat at the address given below. COPYRIGHTPROTECTED 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 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 ii @ ISO and IDF 2008 - All rights reserved ISO 9231:2008(E) IDF139:2008(E) Contents Page Foreword. IV Foreword. 1 Scope 2 Normative references 3 Terms and definitions 4 Principle. 5 Reagents 6 Apparatus 7 Sampling 8 Preparation of test sample.. 8.1 Yogurt and other fermented milks . 8.2 Other milk products.. 9 Procedure. 9.1 Precipitation of fats and proteins and clarification... 9.2 High-performance liquid chromatography (HPLC) 10 Calculation and expression of results.. 10.1 Calculation... 10.2 Expression of results 11 11.1 Interlaboratorytesting.... 11.2 Repeatability... 11.3 Reproducibility... 12 Test report Annex A (informative) Interlaboratory trials ... Bibliography ... @ISO and IDF 2008 -All rights reserved ii