GB 4789.11-2014 (GB4789.11-2014) & related versions
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National Food Safety Standard -- Microbiological Examination of Food Hygiene -- Examination of Streptococcus Hemolyticus
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| GB/T 4789.11-2003 | English | 70 |
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Microbiological examination of food hygiene -- Examination of Streptococcus hemolyticus
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Microbiological examination of food hygiene. Examination of Streptococcus hemolyticus
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Microbiological examination of food hygiene--Examination of streptococcus hemolyticus
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GB 4789.11-2014: PDF in English
GB 4789.11-2014
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard –
Food Microbiological Examination –
Examination of β-type Hemolytic Streptococcus
ISSUED ON. DECEMBER 1, 2014
IMPLEMENTED ON. MAY 1, 2015
Issued by. National Health and Family Planning Commission of the
People's Republic of China
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Terms and Definitions ... 4
3 Equipment and Materials ... 4
4 Culture Media and Reagents ... 5
5 Inspection Procedure ... 5
6 Operation Procedure ... 6
7 Results and Reports ... 7
Appendix A Culture Media and Reagents ... 8
Foreword
This Standard replaces "Microbiological Examination of Food Hygiene - Examination
of Hemolytic Streptococcus" (GB/T 4789.11-2003).
Compared with GB/T 4789.11-2003, this Standard has the following main changes.
- The standard name was modified;
- The "Scope" was modified;
- The "Terms and Definitions" was added;
- The "Equipment and Materials" was modified;
- The "Culture Media and Reagents" was modified;
- The procedure of sample dilution with aseptic normal saline and the bacitracin
sensitivity test were deleted;
- The catalase test was added;
- Appendix A was added.
National Food Safety Standard –
Food Microbiological Examination –
Examination of β-type Hemolytic Streptococcus
1 Scope
This Standard specifies the inspection method for β-type hemolytic streptococcus in
foods.
This Standard is applicable to inspection of β-type hemolytic streptococcus in foods.
2 Terms and Definitions
2.1 β-type hemolysis
Totally transparent hemolytic rings are formed around the bacterial colony, and the
erythrocytes are fully dissolved.
2.2 β-type hemolytic streptococcus
It can produce β-type hemolytic streptococcus pyogenes (or A-group) and
streptococcus agalactiae (or B-group).
3 Equipment and Materials
In addition to the conventional sterilization and cultivation equipment in
microbiological laboratory, other equipment and materials are as follows.
a) Constant temperature incubator. 36°C±1°C;
b) Refrigerator. 2°C~5°C;
c) Anaerobic culture apparatus;
d) Balance. with sensibility of 0.1g;
e) Homogenizer and matched homogenizing bag;
f) Microscope. 10X~100X;
plate is 2 mm~3 mm in diameter, grey-white, semi-transparent, smooth, round, with
protruded surface, neat edge, and β-type hemolysis is formed.
6.3 Identification
6.3.1 Separable pure cultivation
Select five suspicious colonies (if less than five, select all) to inoculate with Columbia
blood agar plate and TSB enrichment broth respectively, then cultivate under
36°C±1°C for 18 h~24 h.
6.3.2 Gram stain microscopy
Select suspicious colony for gram staining microscopic examination. The β-type
hemolytic streptococcus is gram positive, spherical or oval, and generally shaped in
short chain.
6.3.3 Catalase test
Select suspicious colonies to clean glass slide; drop-add appropriate amount of 3%
hydrogen peroxide solution, it is deemed as positive if any bubble is produced
immediately. The catalase of β-type hemolytic streptococcus is negative.
6.3.4 Streptokinase test (optional item)
Suck 0.2 mL of potassium oxalate blood plasma into 0.8 mL of sterilized normal saline
and mix well; then add 0.5 mL of TSB culture solution of suspicious colony after
cultivation under 36°C±1°C for 18 h~24 h and 0.25 mL of 0.25% calcium chloride
solution; oscillate and shake well; place into the water bath of 36°C±1°C for 10 min;
thus the mixture will self-solidify (the solidification degree shall be until that the content
is stagnant when the test tube is upside-down). Cultivate under 36°C±1°C for 24 h
continuously; it is deemed as positive if the solidified body is fully dissolved again;
otherwise, it is negative, the β-type hemolytic streptococcus is positive.
6.3.5 Other inspections
Identify the suspicious colony with biochemical identification kit or biochemical
identification card.
7 Results and Reports
Upon the above test results, report the detected or un-detected hemolytic
streptococcus in every 25 g (mL) of samples.
Nalidixic acid sodium solution 10.0 mL
A.1.3.2 Preparation
Mix the compositions listed in A.1.3.1 well under aseptic condition, pack separately for
standby.
A.2 Columbia CNA blood agar
A.2.1 Compositions
Casein Tryptone 12.0 g
Digestion solution of animal tissue protein 5.0 g
Yeast extract 3.0 g
Beef extract 3.0 g
Corn starch 1.0 g
Sodium chloride 5.0 g
Agar 13.5 g
Polymyxin 0.01 g
Nalidixic acid 0.01 g
Distilled water 1000.0 mL
A.2.2 Preparation
Dissolve the compositions listed in A.2.1 into the distilled water, heat to dissolve,
calibrate the pH value to 7.3±0.2 and sterilize at 121°C for 12 min; after cooling to
around 50°C, add 50 mL of aseptic defibrinated sheep blood, shake well and pour to
the plate.
A.3 Columbia blood agar
A.3.1 Basal medium
A.3.1.1 Compositions
Animal tissue zymolyte 23.0 g
Starch 1.0 g
Sodium chloride 5.0 g
A.4.2 Gram's iodine solution
A.4.2.1 Compositions
Iodine 1.0 g
Kalium iodide 2.0 g
Distilled water 300.0mL
A.4.2.2 Preparation
Firstly mix the iodine with potassium iodide, add a little distilled water into the mixture
and shake sufficiently, wait till the mixture is dissolved completely, and add distilled
water to 300mL.
A.4.3 Safranin solution
A.4.3.1 Compositions
Safranin 0.25 g
95% ethanol 10.0mL
Distilled water 90.0mL
A.4.3.2 Preparation
Dissolve safranin into the ethanol, and dilute with distilled water.
A.4.4 Staining procedure
Fix the smear over the flame of alcohol lamp, drop-add crystal violet staining solution
for staining for 1 min, then wash with water; drop-add gram's iodine solution and wash
with water after 1 min; drop-add 95% ethanol for decoloring for 15 s~30 s until the
staining solution is washed off (don't decolor excessively), then wash with water;
drop-add counterstain for 1 min, wash with water and dry for microscopic examination.
A.5 Tryptone soybean broth (TSB)
A.5.1 Compositions
Tryptone 17.0 g
Soybean peptone 3.0 g
Sodium chloride 5.0 g
Potassium dihydrogen phosphate (anhydrous) 2.5 g
water, mix well and pack separately for standby.
......
| Standard ID | GB 4789.11-2014 (GB4789.11-2014) | | Description (Translated English) | National Food Safety Standard - Microbiological Examination of Food Hygiene - Examination of Streptococcus Hemolyticus | | Sector / Industry | National Standard | | Classification of Chinese Standard | C53 | | Classification of International Standard | 07.100.30 | | Word Count Estimation | 11,190 | | Date of Issue | 2014/12/1 | | Date of Implementation | 2015/5/1 | | Older Standard (superseded by this standard) | GB/T 4789.11-2003 | | Administrative Organization | National Health and Family Planning | | Regulation (derived from) | National Health and Family Planning Committee Announcement 2014 No. 19 | | Issuing agency(ies) | National Health and Family Planning Commission of the People's Republic of China | | Summary | This Standard specifies the food in the ��-hemolytic streptococcus (Streptococcus) test method. This Standard applies to foods ��-hemolytic streptococcus test. |
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