PDF GB/T 20944.2-2007 English
Search result: GB/T 20944.2-2007
| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivered in | Name of Chinese Standard | Status |
| GB/T 20944.2-2007 | English | 105 |
Add to Cart
|
0-9 seconds. Auto-delivery.
|
Textiles - Evaluation for antibacterial activity - Part 2: Absorption method
| Valid |
PDF Preview: GB/T 20944.2-2007
GB/T 20944.2-2007: PDF in English (GBT 20944.2-2007) GB/T 20944.2-2007
GB
NATIONAL STANDARD OF THE
PEOPLE'S REPUBLIC OF CHINA
ICS 59.080.30
W 04
Textiles - Evaluation for antibacterial activity - Part 2:
Absorption method
ISSUED ON: JUNE 14, 2007
IMPLEMENTED ON: JANUARY 01, 2008
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of PRC;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 4
4 Safety precautions ... 5
5 Principles ... 5
6 Devices ... 5
7 Culture medium and reagents ... 6
8 Test bacteria ... 8
9 Cultivation and preparation of test bacterial liquid ... 9
10 Preparation of specimen ... 10
11 Test procedure... 11
12 Calculation and evaluation of results ... 12
13 Test report ... 13
Textiles - Evaluation for antibacterial activity - Part 2:
Absorption method
1 Scope
This part of GB/T 20944 specifies the quantitative test and evaluation method,
for the determination of the antibacterial activity of textiles, by the absorption
method.
This part applies to various textile products, such as down, fibers, yarns, fabrics
and their products.
This part does not involve the evaluation of the safety of antibacterial products.
2 Normative references
The provisions in following documents become the provisions of this part
through reference in this part of GB/T 20944. For the dated references, the
subsequent amendments (excluding corrections) or revisions do not apply to
this part; however, parties who reach an agreement based on this part 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 12490-1990 Textiles - Testing method for color fastness to domestic
and commercial laundering
3 Terms and definitions
The following terms and definitions apply to this part of GB/T 20944.
3.1
Antibacterial activity
The performance of product to inhibit the reproduction of bacteria.
3.2
Control fabric
A 100% cotton fabric, which does not subject to any treatment, is used to
6.10 Two-stage biological safety cabinet.
6.11 Test tubes, flasks and other commonly used laboratory utensils.
7 Culture medium and reagents
The reagents used in the test shall be analytically pure or suitable for
microbiological tests. The test water shall be pure water of analytical pure,
which is used to prepare the microbial culture medium. It can be prepared by
distillation, ion exchange, or filtration with reverse osmosis equipment. It shall
be non-toxic and non-bacteriostatic.
Note: It is recommended to use the existing commercial dehydrated raw materials to
prepare the culture medium. It shall strictly follow the instructions of the relevant
product manufacturer.
7.1 Soy protein broth (TSB)
Tryptone: 15 g
Soy protein: 5 g
Sodium chloride: 5 g
Water: (finally reaching to the volume of) 1000 mL
After sterilization, the pH value is 7.2 ± 0.2.
7.2 Soybean peptone agar medium (TSA)
Tryptone: 15 g
Soy protein: 5 g
Sodium chloride: 5 g
Agar powder: 15 g
Water: (finally reaching to the volume of) 1000 mL
After sterilization, the pH value is 7.2 ± 0.2.
7.3 Nutrient bouillon (NB)
Beef extract: 3 g
Peptone: 5 g
8 Test bacteria
8.1 Strains
The following Gram-positive and one of the Gram-negative strains shall be used.
- Staphylococcus aureus (ATCC 6538): Gram-positive;
- Klebsiella pneumoniae (ATCC 4352): Gram-negative;
- Escherichia coli (8099 or ATCC 11229): Gram-negative.
Note 1: It may use the test bacteria, that are equivalent to the above-mentioned strains,
AND are provided by the culture collection agencies that have joined the World
Federation of Culture Collections (WFCC).
Note 2: Other test strains can be used as needed. The medium composition, culture
temperature, culture method can be adjusted as needed.
8.2 Activation of freeze-dried bacteria
The freeze-dried bacteria are thawed and dispersed in 5 mL of TSB (7.1) into a
suspension state. It is cultured at 37 °C ± 2 °C for 18 h ~ 24 h.
Use an inoculating loop to take the bacterial suspension AND inoculate it on a
TSA (7.2) plate by the line-marking method. It is cultured at 37 °C ± 2 °C for 18
h ~ 24 h.
Take a typical colony from the petri dish AND inoculate it in a TSA (7.2) slant
test tube. Culture it at 37 °C ± 2 °C for 18 h ~ 24 h.
Store the slant test tube in the refrigerator (5 °C ~ 10 °C), as a preservation
bacteria. The storage period does not exceed one month. It is passed once a
month. The number of passages does not exceed 10 generations.
8.3 Identification
The following information shall be marked for each test bacteria:
a) The name of the culture preservation organization, that supplies the
freeze-dried bacteria;
b) The name and number of the freeze-dried bacteria;
c) Lot number of freeze-dried bacteria;
d) Activation date of freeze-dried bacteria;
10 Preparation of specimen
10.1 Sample washing
If evaluating the antibacterial and washing resistance performance, take 3 small
samples from each large sample (each size is 10 cm x 10 cm; cut into 2 pieces).
Wash it, according to the test condition A1M in GB/T 12490-1990. Use the ECE
standard detergent. The end of washing is regarded as 5 washings (the specific
operating conditions and steps equivalent to 5 washings: Use 150 mL of
solution and 10 steel balls, at 40 °C, to wash it for 45 mm; after washing, take
out the specimen; clean it twice in 100 mL of water, at 40 °C, 1 min each time).
After reaching the specified number of washings, use water to thoroughly clean
the sample. Dry it naturally.
10.2 Specimen mass
Select a representative specimen from each sample. Cut it to an appropriate
size. Weigh 0.40 g ± 0.05 g as a specimen. Take 3 specimens for the test of
antibacterial activity, AND 6 control fabrics, respectively.
Note: 3 control fabrics are used to determine the number of bacteria, immediately after
inoculation. The remaining 3 control fabrics and 3 samples for test of antibacterial
activity are used to determine the number of bacteria after bacterial inoculation and
culture.
10.3 Placement of specimen
Place each specimen in a small glass bottle.
a) For fabric specimens that are easy to curl, press a glass rod on it, OR fix
both sides by a thread.
b) The yarn specimen should be tied into a bundle at both ends; a glass rod
shall be pressed on it.
c) For carpets or similar structure samples, cut the raised part of the sample
as a specimen; press a glass rod on it.
d) Press a glass rod on the fluffy specimen of down, fiber, flakes.
10.4 Sterilization of specimen
Choose the sterilization method according to the fiber and treatment type of the
specimen. Generally, autoclave sterilization is used. Use appropriate material
to cover the vials, which contain the specimen, and caps; put them in an
autoclave for sterilization (121 °C,103 kPa, 15 min). Take out the vials and caps
Cover the cap. Place it at room temperature. Prepare 2 plates for one diluent.
After the medium has solidified, turn the plate upside down. Culture at 37 °C ±
2 °C for 24 h~48 h.
After culturing, count the number of colonies (CFU) on the plate, which has 30
~ 300 colonies. If the number of colonies, at the smallest dilution factor, is < 30,
then the actual number is recorded; if no colony grows, the number of colonies
is recorded as "< 1".
Record the number of colonies eluted immediately after inoculation of the 3
control fabrics, as well as the number of colonies in the eluate of the 3
antibacterial activity samples and 3 control fabrics after culturing.
12 Calculation and evaluation of results
12.1 Calculation of the number of bacteria
According to the number of colonies obtained from the two plates, calculate the
number of bacteria according to formula (1):
Where:
M - The number of bacteria in each specimen;
Z - The average value of the number of colonies (CFU) in two plates;
R - The dilution factor;
20 - The amount of eluent consumed, in milliliters (mL).
12.2 Judgment of the validity of test
Calculate the bacterial growth value F, according to formula (2). When F is
greater than or equal to 1.5, the test is judged to be valid; otherwise, the test is
invalid, AND the test is repeated.
Where:
F - The bacterial growth value of the control fabric;
C - The average value of the number of bacteria, which is measured after 3
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
|