IEC PAS 62958:2015

IEC PAS 62958 ®
Edition 1.0 2015-03
PUBLICLY AVAILABLE
SPECIFICATION
PRE-STANDARD
Clothes washing machines for household use – Method for measuring the
microbial contamination reduction
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IEC PAS 62958 ®
Edition 1.0 2015-03
PUBLICLY AVAILABLE
SPECIFICATION
PRE-STANDARD
Clothes washing machines for household use – Method for measuring the

microbial contamination reduction

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 97.060 ISBN 978-2-8322-2478-6

– 2 – IEC PAS 62958:2015 © IEC 2015
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions and symbols. 9
3.1 Terms and definitions . 9
3.2 Symbols . 9
4 Requirements . 10
5 Test conditions, materials, equipment and instrumentation . 10
5.1 Test conditions . 10
5.2 Materials and reagents . 10
5.2.1 Microorganisms for test purposes . 10
5.2.2 Culture media and solutions . 10
5.2.3 Detergent . 13
5.3 Equipment . 14
5.3.1 General . 14
5.3.2 Incubator . 14
5.3.3 Autoclave . 14
5.3.4 Microorganism carrier . 14
5.3.5 Pipettes . 14
5.3.6 Electromechanical agitator. 14
5.3.7 Centrifuge, centrifuge tubes . 14
5.3.8 Base load . 14
5.3.9 Measuring equipment for assessing temperature profile . 15
5.3.10 Measuring equipment for water consumption . 15
6 Tests . 15
6.1 Test method principles . 15
6.2 Preparation of test washing machine . 15
6.3 Preparation of test microorganisms and bio monitors . 15
6.3.1 Cultures . 15
6.3.2 Bio monitors . 17
6.4 Main test . 18
6.4.1 General . 18
6.4.2 Evidence of test microorganisms . 18
6.5 Validation . 18
6.5.1 Enumeration of microorganisms before exposition N (bio monitor
reference) . 18
6.5.2 Negative control (cross contamination) . 18
6.5.3 Determination of water quality . 19
6.5.4 Determination of water quantity in the main wash . 19
7 Evaluation . 19
7.1 Log reduction . 19
7.2 Cross contamination . 19
8 Test report . 19
Annex A (informative) Microorganism reduction in household washing machines with
risk class 1 test microorganisms for internal development purpose . 21

A.1 Scope . 21
A.2 General recommendation . 21
A.3 Material and reagents . 21
A.3.1 Microorganisms on bio monitors . 21
A.3.2 Water for culture media and solutions . 21
A.3.3 Culture media and solutions . 21
A.3.4 Detergent . 23
A.4 Equipment . 23
A.4.1 Incubator . 23
A.4.2 Autoclave . 23
A.4.3 Microorganism carrier . 23
A.4.4 Pipettes . 23
A.4.5 Electromechanical agitator. 23
A.4.6 Centrifuge . 23
A.4.7 Base load . 23
A.4.8 Measuring equipment for assessing temperature profile . 23
A.4.9 Measuring equipment for water consumption . 23
A.5 Tests . 23
A.5.1 Test method principles . 23
A.5.2 Preparation of washing machine . 24
A.5.3 Preparation of test organisms and bio monitors . 24
A.5.4 Main test . 25
A.5.5 Validation . 26
A.6 Evaluation . 26
A.6.1 Plate counts per bio monitor . 26
A.6.2 Log reductions . 27
A.6.3 Cross contamination . 27
A.7 Test report . 27
Annex B (informative) Sources of materials and supplies . 28
B.1 Disclaimer . 28
B.2 Microorganism carriers . 28
B.3 Electromechanical agitator . 28
B.4 Ready-to-use bio monitors . 28
B.5 Nonionic surfactant and emulsifier . 28
Bibliography . 29

Figure A.1 – Scheme for preparing a dilution series . 25

Table 1 – Composition of Tryptone Soy Agar (TSA) . 11
Table 2 – Composition of Sabouraud Dextrose Agar with Chloramphenicol . 11
Table 3 – Composition of Cetrimide Agar . 11
Table 4 – Composition of Baird-Parker Agar . 12
Table 5 – Composition of Malt Extract Agar (MEA) . 12
Table 6 – Composition of Tryptone Soy Broth (TSB) . 12
Table 7 – Composition of diluting agent . 13
Table 8 – Composition of recommended neutralisation solution . 13
Table 9 – Specifications for temperature logger . 15

– 4 – IEC PAS 62958:2015 © IEC 2015
Table A.1 – Composition of Sabouraud Dextrose Agar . 22
Table A.2 – Composition of Columbia CNA Agar .
...