ISO INTERNATIONAL STANDARD 11290-1 Secondedition 2017-05 Microbiology of the food chain Horizontal method for the detection and enumeration of Listeria monocytogenes and of Listeria spp. - Part 1: Detection method Microbiologie de la chaine alimentaire - Méthode horizontale pour la recherche et le dénombrement de Listeria monocytogenes et de Listeria spp. Partie 1: Méthode de recherche Reference number IS0 11290-1:2017(E) International Organization for Standardization @ IS0 2017 ZHEJIANG INST OF STANDARDIZATION C1 5956617 ted without license from IHS IS0 11290-1:2017(E) COPYRIGHTPROTECTEDDOCUMENT IS0 2017, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 [email protected] www.iso.org icensee-ZHEJIANG INST OF STANDARDIZoISQ s31.7 - All rights reserved Not for Resale, 2017/8/21 01:41:39 networking permited without license from IHS IS0 11290-1:2017(E) Contents Page Foreword ..V Introduction. ..vi 1 Scope. 2 Normative references 3 Terms and definitions 4 Principle ..2 4.1 General ..2 4.2 Primary enrichment in a selective liquid enrichment medium with reduced concentration of selective agents (half-Fraser broth). ..2 4.3 Secondary enrichment with a selective liquid enrichment medium with full concentration of selective agents (Fraser broth), ..3 4.4 Plating out and identification .3 4.5 Confirmation ..3 5 Culture media and reagents .3 6 Equipment and consumables 7 Sampling. ..4 8 Preparation of test sample ..4 9 Procedure. .4 9.1 Test portion and initial suspension .4 9.2 Primary enrichment. 4 9.3 Secondary enrichment. .5 9.4 Plating out and identification. 5 9.4.1 General .5 9.4.2 Agar Listeria according to Ottaviani and Agosti 5 9.4.3 Secondselectivemedium .6 9.5 Confirmation of Listeria monocytogenes or Listeria spp. .6 9.5.1 Selection of colonies for confirmation. .6 9.5.2 Confirmation of L. monocytogenes... .6 9.5.3 Confirmation of Listeria spp. .10 9.6 Interpretation of morphological and physiological properties and of the biochemical reactions ..11 9.7 Additional characterization of isolated strains (optional) .11 10 Expression of results .11 11 Performance characteristics of the method. ..11 11.1 Method validation studies. ..11 11.2 Sensitivity .11 11.3 Specificity 11 11.4 Level of detection (LOD5o) .11 12 Test report ..12 13 Quality assurance ..12 Annex A (normative) Diagram of procedure ..13 Annex B (normative) Composition and preparation of culture media and reagents ..14 Annex C (informative) Distinction of Listeria spp. from other genera ..27 Annex D (informative) Reactions for the identification of Listeria species ..28 Annex E (informative) Listeria selective agars ..30 iii icensee=ZHEJIANG INST OF STANDARDIZATION C1 5956617 ed without license from IHS