GB/T 22595-2008 English PDF (GBT22595-2008)

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GB/T 22595-2008: Test method for efficacy of antimicrobials -- Aerobic bacteria
GB/T 22595-2008
ICS 19.020; 71.100.40
G 76
GB
National Standard
of the People’s Republic of China
Test method for efficacy of antimicrobials -
Aerobic bacteria
ISSUED ON. DECEMBER 23, 2008
IMPLEMENTED ON. SEPTEMBER 1, 2009
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration Committee.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Summary of methods ... 4
4 Reagents and materials ... 5
5 Instruments and equipment ... 5
6 Preparation before test ... 6
7 Test methods ... 8
Appendix A ... 11
Appendix B ... 12
Foreword
Appendix A and Appendix B of this Standard are normative.
This Standard was proposed by China Petroleum and Chemical Industry
Federation.
This Standard shall be administrated by Water Treatment Sub-committee of
National Standardization Technical Committee (SAC/TC 63/SC 5).
Responsible drafting organizations of this Standard. Shanghai Future
Enterprises Limited, and CNOOC Tianjin Chemical Research and Design
Institute.
Main drafters of this Standard. Liu Xin, Zhang Quan, Shao Hongqian, and Zhu
Chuanjun.
Test method for efficacy of antimicrobials –
Aerobic bacteria
1 Scope
This Standard specifies the test method for the sterilization efficacy of aerobic
bacteria by using antimicrobial in cooling water system.
This Standard applies to the test for the sterilization efficacy of oxidizing and
non-oxidizing antimicrobial to the aerobic bacteria.
2 Normative references
The provisions in following documents become the provisions of this Standard
through reference in this Standard. For dated references, the subsequent
amendments (excluding corrections) or revisions do not apply to this Standard,
however, parties who reach an agreement based on this Standard are
encouraged to study if the latest versions of these documents are applicable.
For undated references, the latest edition of the referenced document applies.
GB/T 603 Chemical reagent - Preparations of reagent solutions for use in
test methods (GB/T 603-2002, ISO 6353-11982, NEQ)
GB/T 6682 Water for analytical laboratory use - Specification and test
methods (GB/T 6682-2008, ISO 3696. 1987, MOD)
GB/T 14643.1 Industrial circulating cooling water - Examination of bacteria
formed deposits - Standard of plate count
3 Summary of methods
In the sample that contains a certain amount of aerobic bacteria. ADD
antimicrobials quantitatively. SIMULATE antimicrobial’s use conditions (water
quality, pH value, etc.). DETERMINE the amount of aerobic bacteria survived
in the prescribed time period and COMPARE it with the amount of aerobic
bacteria at the beginning of test. CALCULATE the killing rate of this
cooling water, the selection range of concentration of the antimicrobial to be
added shall be in accordance with the characteristics and use conditions of the
antimicrobial. CHOOSE several concentration grades in a certain range to
conduct test.
7.1.3 To make dosing operation more convenient, the original fluid of
antimicrobial to be tested shall be diluted with water before the test. The
degree of dilution shall be based on - after the diluted solution of antimicrobial
is added to the sample, it just reaches the concentration needed in test (the
ratio of the volume of diluted antimicrobial and the volume of sample to be
added shall not exceed 1.100). The diluted solution of antimicrobial shall be
used immediately after it is diluted.
7.2 Test procedure
7.1.1 General test
7.1.1.1 This test is used to choose the appropriate type and appropriate dosing
concentration of antimicrobial.
7.2.1.2 TAKE 200 mL of sample prepared in 6.7 of which the content of aerobic
bacteria is 105 cfu/mL~107 cfu/mL. ADD it to the erlenmeyer flasks (the specific
amount of flask is determined by the total amount and concentration of test
antimicrobial in same batch). STUFF with cotton.
7.1.1.3 DETERMINE the amount of aerobic bacteria survived in the water
samples according to GB/T 14643.1. That is the initial amount of bacteria of
the test of same batch.
7.1.1.4 NUMBER the erlenmeyer flasks. ADD the antimicrobial dilution in 7.1.3
to each flask correspondingly. SHAKE them well.
7.2.1.5 PLACE the entire erlenmeyer flask in a thermostatic biochemical
incubator at (29 ± 1) ºC to culture.
7.2.1.6 DETERMINE the total amount of aerobic bacteria in the erlenmeyer
flask at the 4th hour, 8th hour, 12th hour, 16th hour, 20th hour, 24th hour (the
specific test time is determined according to the characteristics and use
of antimicrobial to conduct test.
B.2.2 Preparation of antimicrobial solutions with different concentrations
DELUTE the original fluid of antimicrobial with the water for test. The degree of
dilution shall be based on - to make the diluted liquor of antimicrobial just
reaching the concentration needed by the test, after adding quantitative culture
medium.
B.2.3 NUMBER the petri dishes. INDICATE the name and concentration of the
selected antimicrobials.
B.2.4 USE sterile pipette to transfer 1 mL of diluted liquor of antimicrobial in
B.2.2. ADD it to the culture dish with corresponding number. And quantitatively
INJECT 10mL~15mL of sterile culture medium that is cooled to about (45 ± 1)
ºC into culture dish immediately. SHAKE them well. COOL it for spare use.
B.2.5 USE micro-injector to take 10 μL of sample of 6.7. PLACE it at the center
of bacteria-bearing culture medium plate (prepared in B.2.4). COVER it with
lid.
B.2.6 PLACE B.2.5 at the appropriate temperature for a certain period of time
(determined according to different test conditions). According to the growth
condition of the sample on the plate containing antimicrobial, DETERMINE the
minimum inhibitory concentration of antimicrobial to the sample, so as to judge
the size of sterilization efficacy of antimicrobial.
Note. The minimum inhibitory concentration method is a quantitative method, it can better
reflect the size of the sterilization efficacy of antimicrobial, and it is convenient to compare the
sterilization efficacy of different antimicrobials. However, the determination data from different
sources are often different, some differences are great, this kind of difference is so difficult to
avoid that even in the tests of different batches in same laboratory.