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 may be subject to current national legislation and regulations. Only personnel trained in microbiological techniques should carry out such tests. Appropriate practices for disinfection, sterilization and personal hygiene must 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 e.g. 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 International Standard, which is not intended to be used or referenced as a method to document or claim biodegradability of, for instance, 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 results obtained should include a reference to this International Standard and the conditions used. Results obtained with this International Standard 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.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (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 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.
If required, other species can also be used, in which case the species and the reason for their use shall be included in the test report.
4.2 Reagents, culture media and solutions
Water shall be distilled or deionized and have a conductivity of < 1 µS/cm.
All reagents shall be of analytical grade and/or of a grade appropriate for microbiological purposes.
4.2.1 Nonionic surfactant
Polyoxyethylene sorbitan monooleate shall be used.
4.2.2 Biological materials
The following biological materials are required:
——lecithin;
——D-glucose;
——yeast extract;
——meat extract (see Annex A);
——peptone (see Annex A);
——casein peptone;
——soybean peptone;
——tryptone.
4.2.3 Culture medium
4.2.3.1 General
The culture medium specified below shall be used. The medium may be obtained from commercial suppliers, in which case it shall be prepared for use in accordance with the manufacturer's instructions.
The quantity of the culture medium can be changed provided the same composition is retained.
4.2.3.2 Suspension medium - 1/500 nutrient broth (1/500 NB)
Prepare nutrient broth by dissolving 3.0 g of meat extract, 10.0 g of peptone and 5.0 g of sodium chloride in 1000 ml of distilled or deionized water. Dilute the nutrient broth with distilled or deionized water to a 500-fold volume and adjust the pH to a value between 6.8 and 7.2 with sodium hydroxide or hydrochloric acid. Sterilize by autoclaving (see 6.2). If it is not used immediately after preparation, store it at 5 °C to 10 °C. A 1/500 NB that has been kept for one week or longer after preparation shall not be used.
4.2.3.3 Nutrient agar
Prepare nutrient agar by dissolving 5.0 g of meat extract, 10.0 g of peptone, 5.0 g of sodium chloride and 15.0 g of agar powder in 1000 ml of distilled or deionized water. Heat, with stirring, on a hotplate or in a boiling-water bath until the agar has dissolved. Adjust the pH to a value between 7.0 and 7.2 (at 25 °C) with sodium hydroxide or hydrochloric acid. Sterilize by autoclaving (see 6.2). If it is not used immediately after preparation, store it at 5 °C to 10 °C. Nutrient agar that has been kept for one month or longer after preparation shall not be used.
4.2.3.4 Plate count agar
Prepare plate count agar by dissolving 2.5 g of yeast extract, 5.0 g of tryptone, 1.0 g of glucose and 15.0 g of agar powder in 1000 ml of distilled or deionized water. Heat, with stirring, on a hotplate or in a boiling-water bath until the agar has dissolved. Adjust the pH to a value between 7.0 and 7.2 (at 25 °C) with sodium hydroxide or hydrochloric acid. Sterilize by autoclaving (see 6.2). If it is not used immediately after preparation, store it at 5 °C to 10 °C. Plate count agar that has been kept for one month or longer after preparation shall not be used.
4.2.3.5 Slant culture medium
Warm 6 ml to 10 ml of nutrient agar and pour into a screw-capped test tube. Sterilize by autoclaving (see 6.2). After sterilization, place the test tube at an angle of about 15° to the horizontal and allow the contents to solidify. If it is not used immediately after preparation, store it at 5 °C to 10 °C. Slant culture medium kept for one month or longer after preparation shall not be used.
4.2.3.6 Soybean casein digest broth with lecithin and polyoxyethylene sorbitan monooleate (SCDLP broth)
Prepare SCDLP broth by dissolving 17.0 g of casein peptone, 3.0 g of soybean peptone, 5.0 g of sodium chloride, 2.5 g of disodium hydrogen phosphate, 2.5 g of glucose and 1.0 g of lecithin in 1000 ml of distilled or deionized water. Mix thoroughly and add 7.0 g of nonionic surfactant. Adjust the pH to a value between 6.8 and 7.2 (at 25 °C) with sodium hydroxide or hydrochloric acid. Sterilize by autoclaving (see 6.2). If it is not used immediately after preparation, store it at 5 °C to 10 °C. SCDLP broth kept for one month or longer after preparation shall not be used.
Note: SCDLP is the default neutralizer in the majority of circumstances. Information about selection and evaluation of alternative antibacterial neutralizing agents can be found in EN 1040[9] and ASTM E1054[10].
4.2.3.7 Phosphate buffer solution
Prepare phosphate buffer solution by placing 34.0 g of potassium dihydrogen phosphate in a 1000 ml volumetric flask. Add 500 ml of distilled or deionized water and mix to dissolve. Adjust the pH to a value between 6.8 and 7.2 (at 25 °C) with sodium hydroxide. Add distilled or deionized water to make up to 1000 ml. Sterilize by autoclaving (see 6.2). Phosphate buffer solution kept for one month or longer after preparation shall not be used.
Standard
GB/T 31402-2023 Measurement of antibacterial activity on plastics and other non-porous surfaces (English Version)
Standard No.
GB/T 31402-2023
Status
valid
Language
English
File Format
PDF
Word Count
8500 words
Price(USD)
255.0
Implemented on
2024-6-1
Delivery
via email in 1~3 business day
Detail of GB/T 31402-2023
Standard No.
GB/T 31402-2023
English Name
Measurement of antibacterial activity on plastics and other non-porous surfaces
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 may be subject to current national legislation and regulations. Only personnel trained in microbiological techniques should carry out such tests. Appropriate practices for disinfection, sterilization and personal hygiene must 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 e.g. 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 International Standard, which is not intended to be used or referenced as a method to document or claim biodegradability of, for instance, 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 results obtained should include a reference to this International Standard and the conditions used. Results obtained with this International Standard 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.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (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 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.
If required, other species can also be used, in which case the species and the reason for their use shall be included in the test report.
4.2 Reagents, culture media and solutions
Water shall be distilled or deionized and have a conductivity of < 1 µS/cm.
All reagents shall be of analytical grade and/or of a grade appropriate for microbiological purposes.
4.2.1 Nonionic surfactant
Polyoxyethylene sorbitan monooleate shall be used.
4.2.2 Biological materials
The following biological materials are required:
——lecithin;
——D-glucose;
——yeast extract;
——meat extract (see Annex A);
——peptone (see Annex A);
——casein peptone;
——soybean peptone;
——tryptone.
4.2.3 Culture medium
4.2.3.1 General
The culture medium specified below shall be used. The medium may be obtained from commercial suppliers, in which case it shall be prepared for use in accordance with the manufacturer's instructions.
The quantity of the culture medium can be changed provided the same composition is retained.
4.2.3.2 Suspension medium - 1/500 nutrient broth (1/500 NB)
Prepare nutrient broth by dissolving 3.0 g of meat extract, 10.0 g of peptone and 5.0 g of sodium chloride in 1000 ml of distilled or deionized water. Dilute the nutrient broth with distilled or deionized water to a 500-fold volume and adjust the pH to a value between 6.8 and 7.2 with sodium hydroxide or hydrochloric acid. Sterilize by autoclaving (see 6.2). If it is not used immediately after preparation, store it at 5 °C to 10 °C. A 1/500 NB that has been kept for one week or longer after preparation shall not be used.
4.2.3.3 Nutrient agar
Prepare nutrient agar by dissolving 5.0 g of meat extract, 10.0 g of peptone, 5.0 g of sodium chloride and 15.0 g of agar powder in 1000 ml of distilled or deionized water. Heat, with stirring, on a hotplate or in a boiling-water bath until the agar has dissolved. Adjust the pH to a value between 7.0 and 7.2 (at 25 °C) with sodium hydroxide or hydrochloric acid. Sterilize by autoclaving (see 6.2). If it is not used immediately after preparation, store it at 5 °C to 10 °C. Nutrient agar that has been kept for one month or longer after preparation shall not be used.
4.2.3.4 Plate count agar
Prepare plate count agar by dissolving 2.5 g of yeast extract, 5.0 g of tryptone, 1.0 g of glucose and 15.0 g of agar powder in 1000 ml of distilled or deionized water. Heat, with stirring, on a hotplate or in a boiling-water bath until the agar has dissolved. Adjust the pH to a value between 7.0 and 7.2 (at 25 °C) with sodium hydroxide or hydrochloric acid. Sterilize by autoclaving (see 6.2). If it is not used immediately after preparation, store it at 5 °C to 10 °C. Plate count agar that has been kept for one month or longer after preparation shall not be used.
4.2.3.5 Slant culture medium
Warm 6 ml to 10 ml of nutrient agar and pour into a screw-capped test tube. Sterilize by autoclaving (see 6.2). After sterilization, place the test tube at an angle of about 15° to the horizontal and allow the contents to solidify. If it is not used immediately after preparation, store it at 5 °C to 10 °C. Slant culture medium kept for one month or longer after preparation shall not be used.
4.2.3.6 Soybean casein digest broth with lecithin and polyoxyethylene sorbitan monooleate (SCDLP broth)
Prepare SCDLP broth by dissolving 17.0 g of casein peptone, 3.0 g of soybean peptone, 5.0 g of sodium chloride, 2.5 g of disodium hydrogen phosphate, 2.5 g of glucose and 1.0 g of lecithin in 1000 ml of distilled or deionized water. Mix thoroughly and add 7.0 g of nonionic surfactant. Adjust the pH to a value between 6.8 and 7.2 (at 25 °C) with sodium hydroxide or hydrochloric acid. Sterilize by autoclaving (see 6.2). If it is not used immediately after preparation, store it at 5 °C to 10 °C. SCDLP broth kept for one month or longer after preparation shall not be used.
Note: SCDLP is the default neutralizer in the majority of circumstances. Information about selection and evaluation of alternative antibacterial neutralizing agents can be found in EN 1040[9] and ASTM E1054[10].
4.2.3.7 Phosphate buffer solution
Prepare phosphate buffer solution by placing 34.0 g of potassium dihydrogen phosphate in a 1000 ml volumetric flask. Add 500 ml of distilled or deionized water and mix to dissolve. Adjust the pH to a value between 6.8 and 7.2 (at 25 °C) with sodium hydroxide. Add distilled or deionized water to make up to 1000 ml. Sterilize by autoclaving (see 6.2). Phosphate buffer solution kept for one month or longer after preparation shall not be used.
