IEC TS 63331:2024

IEC TS 63331 ®
Edition 1.0 2024-09
TECHNICAL
SPECIFICATION
colour
inside
Electric dishwashers for household use – Methods for measuring the
microbiological efficacy of the dishwashing process

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IEC TS 63331 ®
Edition 1.0 2024-09
TECHNICAL
SPECIFICATION
colour
inside
Electric dishwashers for household use – Methods for measuring the

microbiological efficacy of the dishwashing process

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 97.040.40  ISBN 978-2-8322-9738-4

– 2 – IEC TS 63331:2024 © IEC 2024
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms, definitions, symbols and abbreviated terms . 7
3.1 Terms and definitions . 7
3.2 Symbols and abbreviated terms . 10
4 List of measurements . 10
5 Test conditions, materials and reagents . 10
5.1 General information . 10
5.2 General purpose and procedure . 11
5.3 Test conditions . 11
5.3.1 General requirements . 11
5.3.2 Ambient conditions . 11
5.3.3 Water conditions . 11
5.4 Test equipment and material . 12
5.4.1 Load . 12
5.4.2 Test machine . 12
5.4.3 Ballast soil . 12
5.4.4 Detergent . 13
5.4.5 Rinse aid . 13
5.4.6 Salt . 13
5.4.7 General microbiological laboratory equipment . 14
5.4.8 Specific microbiological equipment . 15
5.4.9 Measuring equipment for assessing temperature profile . 18
5.4.10 Measuring equipment for assessing water consumption . 19
6 Tests . 19
6.1 Test programme . 19
6.2 Load . 19
6.2.1 Composition of the test load . 19
6.3 Test machine . 22
6.3.1 Conditioning of new test machines . 22
6.3.2 Cleaning of test machines . 22
6.4 Preparation of bio indicators . 22
6.4.1 Preculture and preparation of bacteria suspension . 22
6.4.2 Preparation of the embedding matrix . 22
6.4.3 Cleaning and conditioning of stainless steel strips/bio indicators . 23
6.4.4 Contamination of stainless steel strips . 23
6.5 Determination of microbial load . 23
6.5.1 Determination of the initial cell count . 23
6.5.2 Determination of the remaining count . 24
6.6 Loading and operating . 24
6.6.1 Loading . 24
6.6.2 Operating . 24
7 Evaluation . 25
7.1 General requirements . 25
7.2 Determination of microbial reduction − Calculation of the reduction factor . 25

7.3 Results . 25
7.3.1 Expression of results . 25
7.3.2 Evaluation of results . 25
8 Test report . 25
8.1 Documentation . 25
8.2 Data in the test report . 26
Annex A (informative) Prediction of microbial inactivation . 27
A.1 General information and purpose . 27
A.1.1 General information . 27
A.1.2 Purpose . 27
A.1.3 Background . 27
A.2 Calculation of MIE unit . 28
A.2.1 Requirements . 28
A.2.2 Calculation . 29
A.2.3 Results . 29
Annex B (informative) Test report . 30
Annex C (informative) Addresses of suppliers . 31
Bibliography . 32

Figure 1 – Stainless steel strip / Bio indicator . 17
Figure 2 – Holders for bio indicators . 18
Figure 3 – Exemplary loading scheme of rack containing bio indicators (13 place
settings) . 21

Table 1 – Recipe for production of ballast soil . 12
Table 2 – Composition of tryptic soy agar . 15
Table 3 – Composition of tryptic soy broth . 15
Table 4 – Composition of sodium chloride solution . 16
Table 5 – Composition of neutralisation solution . 16
Table 6 – Specifications for data sensor . 18
Table 7 – Specifications for measuring equipment for water consumption . 19
Table 8 – Quantity of bio indicators according to rated dishwasher capacity . 20
Table B.1 – Results of tests with bio indicators . 30

– 4 – IEC TS 63331:2024 © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRIC DISHWASHERS FOR HOUSEHOLD USE –
METHODS FOR MEASURING THE MICROBIOLOGICAL
EFFICACY OF THE DISHWASHING PROCESS

FOREWORD
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