ISO INTERNATIONAL STANDARD 21703 First edition 2019-01 Surface active agents Microbiology - Microbiological test methods for liquid hand dishwashing Agents de surface - Microbiologie - Méthodes d'essai microbiologique pour les détergents liquides de lavage de vaisselle alamain Reference number IS0 21703:2019(E) osi @ IS0 2019 IS0 21703:2019(E) COPYRIGHTPROTECTEDDOCUMENT @ IS0 2019 All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 CP 401 : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone: +41 22 749 01 11 Fax: +41 22 749 09 47 Email: copyright@iso.org Website: www.iso.org Published in Switzerland ii @ IS0 2019 - All rights reserved IS0 21703:2019(E) Contents Page Foreword ..V 1 Scope .1 2 Normative references ..1 3 Terms and definitions 4 Principle ..2 5 Diluents and culture media .2 5.1 General .2 5.2 Neutralizing diluent and diluents .2 5.2.1 General. .2 5.2.2 Neutralizing diluent: Fluid casein digest soy lecithin polysorbate 20 medium (SCDLP 20 broth) 3 5.2.3 Diluent for the bacterial suspension (Tryptone sodium chloride solution) 3 5.3 Culture medium for counting. .3 5.3.1 General ..3 5.3.2 Soybean-casein digest agar medium (SCDA) or tryptic soy agar (TSA) .3 5.3.3 Other medium for counting 4 5.4 Culture medium for detection. .4 5.4.1 General. .4 5.4.2 Enrichment broth: Eugon LT 100 broth .5 5.5 Culture media for isolation and identification .5 5.5.1 MacConkey agar medium .5 5.5.2 Levine eosin-methylene blue agar medium (EMB agar medium) 6 5.5.3 Cetrimide agar medium .6 5.5.4 Pseudomonas agar medium for detection of pyocyanin (Pseudomonas agar P)....7 6 Apparatus and glassware 7 7 Strains of microorganisms ..7 8 Handling of the product and laboratory samples ..8 9 Procedure. ..8 9.1 Generalrecommendation ..8 9.2 Preparation of the initial suspension .8 9.3 Enumeration methods. .8 9.3.1 Dilutions for enumeration ..8 9.3.2 Plate-count methods ..8 10 Method for detection and identification .11 10.1 Enrichment .11 10.2 Isolation ..11 10.3 Detection of aerobic mesophilic bacteria. 11 10.4 Detection and Identification of Escherichia coli .11 10.4.1 General. 11 10.4.2 Gram's stain 11 10.4.3 Culture on Levine eosin-methylene blue agar medium (EMB agar medium) 11 10.4.4 Expression of results. 12 10.5 Detection and identification of Pseudomonas aeruginosa 12 10.5.1 General .12 10.5.2 Gram's stain ..12 10.5.3 Oxidasetest ..12 10.5.4 Culture on Pseudomonas agar medium for detection of pyocyanin ..12 10.5.5 Expressionofresults .12 11 Neutralization of the antimicrobial properties of the product ..13 11.1 General ..13 @ IS0 2019 - All rights reserved iii