Measurement of antibacterial activity on plastics and other non-porous surfaces
WARNING - Handling and manipulation of microorganisms which are potentially hazardous requires a high degree of technical competence and shall be subject to current national legislation and regulations. Only personnel trained in microbiological techniques shall carry out such tests. Appropriate practices for disinfection, sterilization and personal hygiene shall be strictly observed.
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).
It 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 GB/T 19275-2003[1], Method B.
Secondary effects of antibacterial treatments, such as the prevention of biodeterioration and odour, are not covered by this document, which is not intended to be used to evaluate the biodegradability of plastics materials. In the case of plastics, biodegradation is covered in ISO 14851[3], ISO 14852[4] and ISO 14855[5] and related standards.
Building materials are excluded, except where they are used in the same manner as treated articles.
Antibacterial-treated textile products are excluded, even if the surfaces are coated or laminated (such products are covered by ISO 20743[7]).
Photocatalytic materials and products are excluded (such materials and products are covered by ISO 27447[8]).
The test results obtained should include a reference to this document and the experimental conditions used. Results obtained with this document indicate antibacterial activity under the specified experimental conditions used, and do not reflect activity under other circumstances where a variety of factors, such as temperature, humidity, different bacterial species, nutrient conditions, etc., have to be considered. A minimum diffusion of the antibacterial agents/chemicals into the test inoculum is necessary with this procedure.
It is recommended that workers consult ISO 7218 in microbiological examination.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
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.
3.1
antibacterial
term describing a state where growth of bacteria on the surfaces of products is suppressed or describing the effect of an antibacterial agent which suppresses the growth of bacteria on the surfaces of products
3.2
antibacterial agent
agent that inhibits the growth of bacteria on the surfaces of products, used either as a surface treatment or as a compounded ingredient
3.3
antibacterial activity
difference in the logarithm of the viable cell counts found on an antibacterial-treated product and an untreated product after inoculation with and incubation of bacteria
3.4
antibacterial effectiveness
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
4.1 Bacteria to be used for the tests
Both of the following species of bacteria shall be used:
a) Staphylococcus aureus;
b) Escherichia coli.
The bacterial strains to be used are shown in Table 1. If bacterial strains obtained from culture collections other than those shown in Table 1 are used, they shall be obtained from a member agency of the World Federation for Culture Collections (WFCC) and shall be the same strains as those shown in Table 1. Prepare stock cultures of these species in accordance with the supplier's directions.
Table 1 Bacterial strains to be used
Contents
Foreword i
Introduction ii
1 Scope
2 Normative references
3 Terms and definitions
4 Materials
4.1 Bacteria to be used for the tests
4.2 Reagents, culture media and solutions
5 Apparatus
6 Sterilization of apparatus and storage of stock cultures
6.1 Dry-heat sterilization
6.2 Autoclaving
6.3 Preparation of glassware
6.4 Maintenance of stock cultures
7 Procedure
7.1 Pre-culture of bacteria
7.2 Preparation of test specimens
7.3 Preparation of test inoculum
7.4 Inoculation of test specimens
7.5 Incubation of the inoculated test specimens
7.6 Recovery of bacteria from test specimens
7.7 Determining the viable bacteria count by the pour plate culture method
8 Test results
8.1 Determination of the number of viable bacteria
8.2 Conditions for a valid test
8.3 Calculation of antibacterial activity
8.4 Antibacterial effect
9 Repeatability and reproducibility
10 Test report
Annex A (Normative) Quality requirements for biological materials
Annex B (Informative) Repeatability and reproducibility
Annex NA (Informative) Calculation of antibacterial rate
Bibliography
