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GB 4789.35-2016 (GB4789.35-2016)

GB 4789.35-2016_English: PDF (GB4789.35-2016)
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GB 4789.35-2016English85 Add to Cart 0--9 seconds. Auto-delivery National food safety standard -- Microbiological examination of food -- Examination of lactic acid bacteria Valid GB 4789.35-2016

BASIC DATA
Standard ID GB 4789.35-2016 (GB4789.35-2016)
Description (Translated English) National food safety standard -- Microbiological examination of food -- Examination of lactic acid bacteria
Sector / Industry National Standard
Classification of Chinese Standard X09
Word Count Estimation 10,162
Date of Issue 2016-12-23
Date of Implementation 2017-06-23
Older Standard (superseded by this standard) GB 4789.35-2010; SN/T 1941.1-2007
Regulation (derived from) National Health and Family Planning Commission Notice No.17 of 2016

Standards related to: GB 4789.35-2016

GB 4789.35-2016
GB
NATIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
National food safety standard – Microbiological
examination of food – Examination of lactic acid bacteria
ISSUED ON. DECEMBER 23, 2016
IMPLEMENTED ON. JUNE 23, 2017
Issued by. National Health and Family Planning Commission of the PRC;
State Food and Drug Administration.
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Table of contents
Foreword ... 3 
1 Scope ... 4 
2 Terms and definitions ... 4 
3 Equipment and materials ... 4 
4 Medium and reagents ... 4 
5 Testing procedures ... 5 
6 Operating procedures ... 6 
7 Results and reports ... 10 
8 Identification of lactic acid bacteria (optional) ... 10 
Appendix A Medium and reagents ... 12 
Foreword
This standard replaces GB 4789.35-2010 “National food safety standard –
Microbiological examination of food – Examination of lactic acid bacteria” AND
SN/T 1941.1-2007 “Detection of lactic acid bacteria in food for import and
export – Part 1. isolation and enumeration method”.
As compared with GB 4789.35-2010, the main changes of this standard are as
follows.
- ADD the selection and result description of the enumeration and culture
conditions for total number of lactic acid bacteria;
- MODIFY the modified MRS medium components;
- MODIFY the plate count inoculation method and inoculation amount.
National food safety standard – Microbiological
examination of food – Examination of lactic acid bacteria
1 Scope
This standard specifies the testing method of the lactic acid bacteria in the food
containing lactic acid bacteria.
This standard is applicable to the testing of lactic acid bacteria in foods
containing active lactic acid bacteria.
2 Terms and definitions
2.1
Lactic acid bacteria
It is a general term of the bacteria for which the fermentable sugars mainly
produce large amounts of lactic acid. The lactic acid bacteria in this
standard are mainly Lactobacillus, Bifidobacterium and Streptococcus.
3 Equipment and materials
In addition to routine sterilization and culture equipment for microbiological
laboratories, other equipment and materials are as follows.
3.1 Constant temperature incubator. 36 °C ± 1 °C.
3.2 Refrigerator. 2 °C ~ 5 °C.
3.3 Homogenizer and sterile homogeneous bag, homogeneous cup or
sterilized mortar.
3.4 Balance. sensitivity of 0.01 g.
3.5 Sterile test tube. 18 mm × 180 mm, 15 mm × 100 mm.
3.6 Sterile pipettes. 1 mL (with 0.01 mL scale), 10 mL (with 0.1 mL scale) OR
micro pipette and suction head.
3.7 Sterile conical flask. 500 mL, 250 mL.
4 Medium and reagents
4.1 Normal saline. SEE A.1.
In accordance with the estimation of the content of the Bifidobacterium
contained in the sample under test, SELECT 2 ~ 3 continuous appropriate
dilutions. For each dilution, ABSORB 1 mL of sample homogenate into a sterile
plate; PREPARE two places for each dilution. After transferring the diluent into
the plate, POUR 15 mL of Li-Mupirocin and Cysteine Hydrochloride modified
MRS agar culture medium which are cooled to 48 °C into each plate; ROTATE
the plate to mix it uniformly. CULTURE it in the 36 °C ± 1 °C anaerobic
environment for 72 h ± 2 h; after culture, COUNT the number of colonies on the
plate. The duration from sample dilution to the plate pouring shall be finished
within 15 min.
6.2.3.3 Count of Streptococcus
In accordance with the estimation of the viable cell number of Streptococcus,
SELECT 2 ~ 3 continuous appropriate dilutions; for each dilution, ABSORB 1
mL of sample homogenate into a sterile plate; PREPARE two plates for each
dilution. After transferring the diluent into the plate, POUR about 15 mL of MC
culture medium which is cooled to 48 °C into the plate; ROTATE the plate to
mix it uniformly. CULTURE it in the 36 °C ± 1 °C aerobic environment for 72 h ±
2 h; after culture, COUNT the number. The colonies of the Streptococcus on
the MC agar plate are characterized by. colony size is medium to small, the
colony is red with neat and smooth edge, the diameter is 2 mm ± 1 mm, AND
the colony back is pink. The duration from sample dilution to the plate pouring
shall be finished within 15 min.
6.2.3.4 Count of Lactobacillus
In accordance with the estimation of the viable cell number of the sample
under test, SELECT 2 ~ 3 continuous appropriate dilutions; for each dilution,
ABSORB 1 mL of sample homogenate into a sterile plate; PREPARE two
plates for each dilution. After transferring the diluent into the plate, POUR
about 15 mL of MC agar culture medium which is cooled to 48 °C into the plate;
ROTATE the plate to mix it uniformly. CULTURE it in the 36 °C ± 1 °C
anaerobic environment for 72 h ± 2 h. The duration from sample dilution to the
plate pouring shall be finished within 15 min.
6.3 Count of colony
Note. it may make observation using naked eyes, AND if necessary USE a
magnifying glass or colony counter; RECORD the dilution factor and the
corresponding number of colonies. The colony count is expressed in
colony-forming units (CFU).
6.3.1 SELECT the plate wherein the number of colonies is between 30 CFU ~
300 CFU AND there is no colony spreading growth to count the total number of
colonies. RECORD the actual number of colonies for the plate having less than
30 CFU, and the plate having more than 300 CFU can be recorded as
countless. The number of colonies per dilution shall use the average of two
plates.
Appendix A
Medium and reagents
A.1 Physiological saline
A.1.1 Ingredients
NaCl. 8.5 g
A.1.2 Methodology
ADD the above ingredient into 1000 mL distilled water; HEAT to dissolve it;
SEPARATE it and MAKE it be autoclaved at 121 ° C for 15 min ~ 20 min.
A.2 MRS medium
A.2.1 Ingredients
Peptone. 10.0 g
Beef powder. 5.0 g
Yeast powder. 4.0 g
Glucose. 20.0 g
Tween 80. 1.0 mL
K2HPO4 • 7H2O. 2.0 g
Sodium acetate • 3H2O. 5.0 g
Triodium citrate. 2.0 g
MgSO4 • 7H2O. 0.2 g
MnSO4 • 4H2O. 0.05 g
Agar powder. 15.0 g
A.2.2 Methodology
ADD the above ingredient into 1000 mL distilled water; HEAT to dissolve it;
ADJUST the pH to 6.2 ± 0.2; SEPARATE it and MAKE it be autoclaved at 121 °
C for 15 min ~ 20 min.
A.3 Li-Mupirocin and Cysteine Hydrochloride modified MRS medium
Peptone. 5.0 g
Yeast extract. 5.0 g
Tween 80. 0.5 mL
Agar. 1.5 g
1.6% bromocresol purple alcohol solution. 1.4 mL
Distilled water. 1000 mL
A.5.2 Methodology
ADD the required carbohydrate by 0.5%; CONTAIN it into small test tubes;
MAKE it be autoclaved at 121 ° C for 15 min ~ 20 min.
A.6 Aescinate medium
A.6.1 Ingredients
Peptone. 5.0 g
Dipotassium phosphate. 1.0 g
Aescinate. 3.0 g
Citric acid. 0.5 g
1.6% bromocresol purple alcohol solution. 1.4 mL
Distilled water. 100 mL
A.6.2 Methodology
ADD the above ingredients into distilled water; HEAT to dissolve it; MAKE it be
autoclaved at 121 ° C for 15 min ~ 20 min.
A.7 Gram stain
A.7.1 Crystal violet dyeing solution
A.7.1.1 Ingredients
Crystal violet. 1.0 g
95% ethanol. 20 mL
1% ammonium oxalate aqueous solution. 80 mL
A.7.1.2 Methodology
...