GB/T 21551.2-2024 English PDF (GB/T21551.2-2024)

GB/T 21551.2-2024: Antimicrobial and cleaning function of household and similar electrical appliances - Part 2: Particular requirements for material
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GB/T 21551.2-2024
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 97.030
CCS Y 60
Replacing GB 21551.2-2010
Antimicrobial and Cleaning Function of Household and
Similar Electrical Appliances - Part 2.Particular
Requirements for Material
ISSUED ON. DECEMBER 31, 2024
IMPLEMENTED ON. JANUARY 1, 2027
Issued by. State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword... 3
Introduction... 6
1 Scope... 8
2 Normative References... 8
3 Terms and Definitions... 9
4 Technical Requirements... 9
5 Test Methods... 10
6 Inspection Rules... 11
7 Marking and Usage Annotations... 13
Appendix A (normative) Test Method for the Antimicrobial Performance of Materials
... 14
Appendix B (normative) Test Method for the Antimicrobial Performance of
Components and Parts... 24
Appendix C (normative) Test Method for the Preventing Mildew Performance of
Materials... 27
Appendix D (normative) Test Method for the Preventing Mildew Performance of
Components and Parts... 33
Appendix E (normative) Test Method for the Antiallergenic Performance... 36
Appendix F (normative) Test Method for the Antiviral Performance... 40
Appendix G (informative) Catalogue of Antimicrobial, Preventing Mildew,
Antiallergenic, Antiviral Materials and Components and Parts of Household and
Similar Electrical Appliances... 46
Bibliography... 48
Antimicrobial and Cleaning Function of Household and
Similar Electrical Appliances - Part 2.Particular
Requirements for Material
1 Scope
This document specifies the technical requirements for the antimicrobial, preventing mildew,
antiallergenic and antiviral performance of materials and components and parts used by
household and similar electrical appliances (hereinafter referred to as “household appliances”),
and describes the corresponding test methods.
This document is applicable to the effectiveness evaluation of the antimicrobial, preventing
mildew, antiallergenic and antiviral performance of household appliances that use antimicrobial,
preventing mildew, antiallergenic and antiviral materials and related components and parts.
2 Normative References
The contents of the following documents constitute indispensable clauses of this document
through the normative references in the text. In terms of references with a specified date, only
versions with a specified date are applicable to this document. In terms of references without a
specified date, the latest version (including all the modifications) is applicable to this document.
GB/T 2829 Sampling Procedures and Tables for Periodic Inspection by Attributes (apply to
inspection of process stability)
GB/T 4288-2018 Household and Similar Electrical Washing Machine
GB 4789.2 National Food Safety Standard - Microbiological Examination of Food. Aerobic
Plate Count
GB/T 4789.15 National Food Safety Standard - Food Microbiological Examination.
Enumeration of Molds and Yeasts
GB/T 6682 Water for Analytical Laboratory Use - Specification and Test Methods
GB/T 8170 Rules of Rounding off for Numerical Values and Expression and Judgement of
Limiting Values
GB/T 17219 Standard for Safety Evaluation of Equipment and Protective Materials in Drinking
Water System
GB 19489 Laboratories - General Requirements for Biosafety
5.3.2 The antimicrobial performance of the components and parts shall be tested in accordance
with the method specified in Appendix B.
5.4 Preventing Mildew
5.4.1 The preventing mildew performance of the materials shall be tested in accordance with
the method specified in Appendix C.
5.4.2 The preventing mildew performance of the components and parts shall be tested in
accordance with the method specified in Appendix D.
5.5 Antiallergen
The antiallergenic performance shall be tested in accordance with the method specified in
Appendix E.
5.6 Antivirus
The antiviral performance shall be tested in accordance with the method specified in Appendix
F.
5.7 Attenuation Test
5.7.1 Water treatment
The materials and components and parts in contact with water shall be immersed in distilled
water at a temperature of (50  1) C or (80  1) C for 16 h. Non-absorbent test samples shall
be placed at room temperature for 2 h. Absorbent test samples shall be placed at room
temperature for 24 h, then, be pre-treated in accordance with the requirements of 5.1.2, and
tested in accordance with the corresponding appendix.
For the materials used at lower temperatures (< 40 C), the attenuation test uses 50 C treatment.
For the materials used at higher temperatures ( 40 C), the attenuation test uses 80 C treatment.
5.7.2 Air treatment
For the materials and components and parts in contact with air, after being dried in an oven at
(50  1) C or (80  1) C for 16 h, the test samples shall be placed at room temperature for 2
h, then, pre-treated in accordance with the requirements of 5.1.2, and tested in accordance with
the corresponding appendix.
For the materials used at lower temperatures (< 40 C), the attenuation test uses 50 C treatment.
For the materials used at higher temperatures ( 40 C), the attenuation test uses 80 C treatment.
6 Inspection Rules
6.1 Type inspection shall be carried out in one of the following situations.
Appendix A
(normative)
Test Method for the Antimicrobial Performance of Materials
A.1 Test Principle
The bacterial solution is quantitatively inoculated on the samples to be tested and the control
samples, and through film application or other applicable methods, the bacteria are evenly
contacted with the samples. After a certain period of culture, determine the number of residual
live bacteria in the two groups of samples, and calculate the antimicrobial rate and antimicrobial
logarithmic value of the samples.
A.2 Test Environment and Operation Requirements
The test shall adopt aseptic operation techniques. The laboratory environment, test operation
and other parts involving biosafety shall comply with the requirements of GB 19489.
A.3 Bacterial Species, Culture Medium, Instruments and Equipment
A.3.1 Bacterial species
The preferred species for testing.
---Staphylococcus aureus subsp. aureus (CGMCC 1.2910, which is equivalent to ATCC
6538P);
---Escherichia coli (CGMCC 1.2463, which is equivalent to ATCC 8739).
Based on the use requirements of household appliances, other bacterial species or strains may
also be selected as test bacteria, but all bacterial species or strains shall be provided by the
relevant national bacterial species preservation and management institutions, and the names and
classification codes of the test bacterial species shall be indicated in the report.
Laboratories shall use test microorganisms in accordance with relevant national safety
regulations. If other test pathogens are selected, the laboratories shall have a biosafety
protection level that is compatible with the hazards and shall not involve the first and second
categories of pathogenic microorganisms in the Catalogue of Pathogenic Microorganisms
Transmissible to Humans.
The various culture medium components used to culture bacterial species shall comply with the
requirements of the bacterial species preservation and management institutions.
A.3.2 Culture media
A.3.2.1 Preparation of nutrient broth (NB) medium
---Biochemical incubator. with a temperature control accuracy of  1 C;
---Oscillating incubator (150 r/min, 200 r/min). with a temperature control accuracy of 
1 C;
---Constant temperature and humidity incubator. with a temperature control accuracy of 
1 C, and a relative humidity of  90%;
---Electric drying oven. room temperature ~ 200 C;
---High pressure steam sterilizer. 121 C, 20 min or 115 C, 30 min;
---Conical flask or wide-mouth bottle. 250 mL;
---Pipette. with an accuracy of 0.01 mL;
---Inoculation loop, alcohol lamp, vortex mixer and other commonly used equipment in
microbiology laboratories.
A.4 Preservation and Activation of Bacterial Species
A.4.1 Preservation of bacterial species
Inoculate the standard bacterial strain on a NA slant, at (37  1) C, culture for 24 h, and then,
preserve it at 5 C ~ 10 C (shall not exceed 1 month) as slant-preserved species.
A.4.2 Activation of bacterial species
Transfer the slant-preserved species to a NA plate, and (37  1) C, culture for (24  1) h,
transferring once a day. During the test, fresh bacterial cultures of the 3rd ~ 5th generations
transferred within 24 hours shall be used.
A.5 Test Methods
A.5.1 Film application method
A.5.1.1 Overview
This method is used to test the antimicrobial performance of non-absorbent materials that can
be made into a certain area.
A.5.1.2 Test material requirements
A.5.1.2.1 Test samples
The sample to be tested can be made of antimicrobial components or homogeneous materials
using the same process, with a size of (50  2) mm  (50  2) mm, or the area to be tested must
be no less than 1,600 mm2.
NOTE. SCDLP is a commonly used neutralizing agent.
A.5.1.3.2 Preparation of inoculation culture solution
The inoculation culture solution is prepared with physiological saline solution containing NB.
For the inoculation culture solution for Escherichia coli, add 0.2% (volume fraction) NB to the
physiological saline solution; for the inoculation culture solution for Staphylococcus aureus
subsp. aureus, add 1.0% (volume fraction) NB to the physiological saline solution. To facilitate
bacterial dispersion, a small amount of surfactant Tween-80 may be added. Use 0.1 mol/L
NaOH solution or 0.1 mol/L HCl solution to adjust the pH after sterilization to 7.0 ~ 7.2.Divide
the contents into portions, and at 121 C, sterilize them in a pressure steam sterilizer for 20 min.
A.5.1.3.3 Preparation of bacterial suspension
Use an inoculation loop to scrape 1 ~ 2 loops of fresh bacteria from the fresh culture on the
plate where the bacterial species have been activated, add them to the culture solution, and
successively perform 10-fold gradient dilutions. Select the diluent with a bacterial solution
concentration of 5.0  105 CFU/mL ~ 1.0  106 CFU/mL as the test bacterial solution, and count
in accordance with the method in GB 4789.2.
A.5.1.4 Test steps
The antimicrobial performance test by the film application method is carried out in accordance
with the following steps.
a) Place the pre-treated test samples and control samples in sterilized culture dishes;
b) Respectively take 0.2 mL of the test bacterial suspension and dropwise add it on the
test samples and the control samples. Perform 3 parallel tests on each group of
samples;
c) Use sterile tweezers to pick up the sterile covering film and respectively use it to cover
the test samples and control samples, flatten it to avoid generating bubbles, so that the
bacterial solution is evenly in contact with the samples, put on the cover, and at (37 
1) C and a relative humidity of not less than 90%, culture for 24 hours;
NOTE. the contact culture time can be adjusted in accordance with the specific situation, but the
maximum time shall not exceed 24 hours.
d) Take out the samples after 24 h of culture, respectively add 20 mL of eluent,
repeatedly wash the test samples, control samples and covering film. After thoroughly
shaking, dilute the eluent in gradients and inoculate into NA, at (37  1) C, culture
for 24 h ~ 48 h, and count the viable bacteria. In accordance with GB 4789.2,
determine the number of viable bacteria in the eluent.
A.5.2 Absorption method
A.5.2.1 Overview
A.5.2.3.2 Preparation of bacterial suspension
Use an inoculation loop to inoculate the activated bacterial species into NB, and at (37  1) C,
culture for (24  2) h. After the culture is completed, shake the liquid culture, let it stand for 15
min ~ 20 min, and use 0.85% (mass fraction) ice-cold saline at 0 C ~ 4 C to dilute it to 5.0 
105 CFU/mL ~ 1.0  106 CFU/mL to prepare a bacterial suspension for the test. If the specimen
has poor water absorption, 0.05% (volume fraction) non-ionic surfactant Tween-80 may be
added to the bacterial suspension.
A.5.2.4 Test steps
The antimicrobial performance test by the absorption method is carried out in accordance with
the following steps.
a) Respectively place the sterilized test samples and control samples in 250 mL sterile
conical flasks or wide-mouth bottles, and perform 3 parallel tests for each group of
samples;
b) Respectively use a pipette to pipette (1.0  0.1) mL of the prepared bacterial
suspension and dropwise add it onto the test samples and control samples, ensuring
that the bacterial solution is evenly distributed and does not touch the bottle wall.
Tighten the stopper / cap to prevent evaporation;
c) Place the conical flasks or wide-mouth bottles containing the test samples and control
samples at (37  1) C to culture for 24 h;
NOTE. the contact time can be adjusted in accordance with the specific situation, but the maximum
time shall not exceed 24 hours.
d) After stationary culture, respectively add 100 mL of sterile PBS to the bottles
containing the test samples and control samples, let them stand for 5 min; place them
on an oscillator, and at a speed of 200 r/min, thoroughly oscillate them for 1 min.
Perform gradient dilutions and pour onto a NA plate. In accordance with GB 4789.2,
determine the number of viable bacteria in the eluent.
A.5.3 Oscillation method
A.5.3.1 Overview
This method is used to test the antimicrobial performance of absorbent or non-absorbent
materials with irregular shapes.
A.5.3.2 Test material requirements
A.5.3.2.1 Test samples
Directly cut from the sample to be tested after antimicrobial treatment, and the size is (10  1)
mm  (10  1) mm. If it is inconvenient to prepare samples of this volume for antimicrobial
Appendix B
(normative)
Test Method for the Antimicrobial Performance of Components and Parts
B.1 Test Principle
By quantitatively inoculating bacteria at design...