GB/T 31402-2023Measurement of antibacterial activity on plastics and other non-porous surfaces (English PDF)

Foreword

This Document was drafted as per the rules specified in GB/T 1.1-2020 Directives for

Standardization – Part 1.Rules for the Structure and Drafting of Standardizing Documents.

This Document replaced GB/T 31402-2015 Plastics - Measurement of Antibacterial Activity on

Plastics Surfaces. Compared with GB/T 31402-2015, the major technical changes of this

Document are as follows besides structural adjustments and editorial modifications.

a) Change the "Scope" to expand the scope of application from plastics to plastics and other

non-porous materials; and add descriptions of materials and products not covered by this

Document (see Clause 1 of this Edition; Clause 1 of the 2015 Edition);

b) Change the requirements for the use of "test bacteria" (see 4.1 of this Edition; 4.1 of the

2015 Edition);

c) Change the requirements for cleaning the specimen in "Preparation of specimens" (see

1 Scope

This Document specifies a method of evaluating the antibacterial activity of antibacterial-

treated plastics, and other non-porous, surfaces of products (including intermediate products).

This Document is not intended to be used to evaluate the effects and propagation of bacteria on

non-porous surfaces without antibacterial treatments. If evaluation is required, see Method B

in GB/T 19275-2003[1].

2 Normative References

The provisions in following documents become the essential provisions of this Document

through reference in this Document. For the dated documents, only the versions with the dates

indicated are applicable to this Document; for the undated documents, only the latest version

(including all the amendments) is applicable to this Document.

ISO 7218 Microbiology of food and animal feeding stuffs – General requirements and

guidance for microbiological examinations

3 Terms and Definitions

For the purposes of this document, the following terms and definitions apply.

Ability of an antibacterial agent to inhibit the growth of bacteria on the surface of materials

treated with an antibacterial agent, as determined by the value of the antibacterial activity.

4 Materials

Prepare physiological saline by placing 8.5 g of sodium chloride in 1 000 ml of distilled or

deionized water and mixing to dissolve. Dilute the phosphate buffer solution prepared in 4.2.3.7

with the physiological saline to an 800-fold volume. Sterilize the phosphate-buffered

physiological saline solution by autoclaving (see 6.2). If this solution is not used immediately

after preparation, store it at 5 °C to 10 °C. Phosphate-buffered physiological saline kept for one

month or longer after preparation shall not be used.

5 Apparatus

Unless otherwise specified, use the following apparatus and materials.

6 Sterilization of Apparatus and Storage of Stock Cultures

Stock cultures shall be stored at 5 °C to 10 °C on an appropriate medium and transferred

monthly. After five transfers or if more than one month has passed between transfers, the stock

culture shall be discarded and replaced with a fresh culture obtained from the institute or culture

collection concerned.

7 Procedure

Testing shall be performed on at least three specimens from each treated test material. At least

six specimens of the untreated material are required. Half of the untreated test specimens are

used to measure viable cells immediately after inoculation and half are used to measure viable

cells after incubation for 24 h.

Using a sterile inoculating loop, transfer one loop of the test bacteria, pre-incubated as specified

in 7.1, into a small amount of 1/500 NB prepared in accordance with 4.2.3.2.Ensure that the

test bacteria are evenly dispersed, and estimate the number of bacteria using direct microscopic

observation and a counting chamber or another appropriate method (e.g.

8 Expression of Results

For each test specimen, determine the number of viable bacteria recovered in accordance with

Equation (1).

The value of the antibacterial activity can be used to characterize the effectiveness of an

antibacterial agent.

9 Repeatability and Reproducibility

Repeatability and reproducibility are discussed quantitatively in Annex B.

10 Test Report

The test report shall include the following information.

Annex A

(Normative)

Quality of Biological Materials

The quality of the components used in the inoculum preparations might differ depending on the

source, and this might cause significant variability in results. Therefore, the composition of the

components used needs to be specified.

Annex B

(Informative)

Repeatability and Reproducibility

The content of this annex is based on the results of extensive research conducted to investigate

the repeatability and reproducibility of the results from this method.

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