GB 4789.2-2022_English: PDF (GB4789.2-2022)
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National food safety standard - Microbiological examination of food: Aerobic plate count
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National food safety standard -- Food microbiological examination -- Aerobic plate count
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GB 4789.2-2010 | English | 70 |
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National food safety standard -- Food microbiological examination: Aerobic plate count
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GB/T 4789.2-2008 | English | 319 |
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Microbiological examination of food hygiene -- Aerobic plate count
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GB/T 4789.2-2003 | English | 199 |
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Microbiological examination of food hygiene -- Detection of aerobic bacterial count
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GB 4789.2-1994 | English | RFQ |
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Microbiological examination of food hygiene. Detection of aerobic bacterial count
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GB 4789.2-1994
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GB 4789.2-1984 | English | RFQ |
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Microbiological examination of food hygiene--Detection of aerobic bacterial count
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GB 4789.2-1984
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Standard ID | GB 4789.2-2022 (GB4789.2-2022) | Description (Translated English) | National food safety standard - Microbiological examination of food: Aerobic plate count | Sector / Industry | National Standard | Classification of Chinese Standard | X09 | Word Count Estimation | 10,191 | Date of Issue | 2022-06-30 | Date of Implementation | 2022-12-30 | Older Standard (superseded by this standard) | GB 4789.2-2016 | Administrative Organization | National Health Commission | Issuing agency(ies) | State Administration for Market Regulation | Standard ID | GB 4789.2-2016 (GB4789.2-2016) | Description (Translated English) | National food safety standard -- Food microbiological examination -- Aerobic plate count | Sector / Industry | National Standard | Classification of Chinese Standard | X09 | Word Count Estimation | 8,837 | Date of Issue | 2016-12-23 | Date of Implementation | 2017-06-23 | Older Standard (superseded by this standard) | GB 4789.2-2010 | Regulation (derived from) | National Health and Family Planning Commission Notice No.17 of 2016 | Standard ID | GB 4789.2-2010 (GB4789.2-2010) | Description (Translated English) | National food safety standard - Food microbiological examination: Aerobic plate count | Sector / Industry | National Standard | Classification of Chinese Standard | C53 | Classification of International Standard | 07.100.30 | Word Count Estimation | 8,866 | Date of Issue | 2010-03-26 | Date of Implementation | 2010-06-01 | Older Standard (superseded by this standard) | GB/T 4789.2-2008 | Regulation (derived from) | Circular of the Ministry of Health (2010)7 | Issuing agency(ies) | Ministry of Health of People's Republic of China | Summary | This Chinese standard specifies the total number of colonies in food (Aerobic plate count) measurement method. This standard applies to the determination of the total number of colonies in foods. |
GB 4789.2-2022
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National food safety standard - Microbiological examination
of food: Aerobic plate count
ISSUED ON: JUNE 30, 2022
IMPLEMENTED ON: DECEMBER 30, 2022
Issued by: National Health Commission of the PRC;
State Administration for Market Regulation.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Terms and definitions ... 4
3 Equipment and materials ... 4
4 Medium and reagents ... 5
5 Examination procedure ... 5
6 Operation steps ... 6
7 Result and report ... 8
Appendix A Medium and reagents ... 10
Appendix B Examples ... 12
National food safety standard - Microbiological examination
of food: Aerobic plate count
1 Scope
This Standard specifies the method for the determination of aerobic plate count in food.
This Standard applies to the determination of aerobic plate count in food.
2 Terms and definitions
2.1
Aerobic plate count
The total number of microbiological colonies formed in per g (mL) of test sample,
which is obtained after the food sample under test is processed and cultured under
certain conditions (such as culture medium, culture temperature, and incubation time,
etc.).
3 Equipment and materials
In addition to the routine sterilization and culture equipment in the microbiology
laboratory, other equipment and materials are as follows:
a) Constant-temperature incubator: 36 ℃±1 ℃, 30 ℃±1 ℃.
b) Refrigerator: 2 ℃~5 ℃.
c) Thermostat: 48 ℃±2 ℃.
d) Balance: Sensitivity is 0.1 g.
e) Homogenizer.
f) Oscillator.
g) Sterile straw: 1 mL (with 0.01 mL scale), 10 mL (with 0.1 mL scale) or
micropipette and tip.
h) Sterile conical flask: Capacity is 250 mL and 500 mL.
6.1.2 Liquid sample: Use a sterile straw to pipette 25 mL of sample; place it in a sterile
conical flask containing 225 mL of sterile phosphate buffer or sterile normal saline (an
appropriate number of sterile glass beads can be preset in the bottle); and mix
thoroughly. Or put it into a sterile homogeneous bag containing 225 mL of diluent. Use
a slap-type homogenizer to beat for 1 min~2 min, to make a 1:10 sample homogenate.
When the result is required to be the aerobic plate count per g of sample, operate
according to 6.1.1.
6.1.3 Use a 1 mL sterile straw or micropipette to draw 1 mL of the 1:10 sample
homogenate; along the tube wall, slowly inject it into a sterile test tube containing 9 mL
of diluent (be careful not to touch the surface of the diluent with the pipette or the tip).
Oscillate and mix on an oscillator, to make a 1:100 sample homogenate.
6.1.4 According to the operation in 6.1.3, prepare a 10-fold serial dilution of the sample
homogenate. For each incremental dilution, use a new 1 mL sterile straw or tip.
6.1.5 According to the estimation of the contamination status of sample, select 1 to 3
sample homogenates with appropriate dilution (liquid samples can include stock
solution). Pipette 1 mL of the sample homogenate into a sterile petri dish; make two
petri dishes for each degree of dilution. At the same time, respectively pipette 1 mL of
blank diluent; add it to two sterile petri dishes as blank control.
6.1.6 In a timely manner, pour 15 mL~20 mL of plate count agar medium cooled to
46 °C~50 °C (which can be kept in a thermostat at 48 °C±2 °C) into a petri dish; rotate
the petri dish to make it evenly mixed.
6.2 Culture
6.2.1 Place horizontally until the agar solidifies; turn the plate over; incubate at
36 °C±1 °C for 48 h±2 h. Aquatic products are cultured at 30 °C±1 °C for 72 h±3 h. If
the sample may contain colonies that spread and grow on the surface of the agar
medium, it is possible to cover the surface of the solidified agar medium with a thin
layer of plate count agar medium (about 4 mL). After solidification, turn the plate over
and culture.
6.2.2 If the test piece of aerobic plate count is used, it shall be operated in accordance
with the relevant technical regulations provided for the test piece.
6.3 Colony count
6.3.1 It is possible to use the naked eye to observe. If necessary, use a magnifying glass
or a colony counter, to record the dilution ratio and the corresponding number of
colonies. Colony counts are expressed in colony forming unit (CFU).
6.3.2 Select the plate with the colony number between 30 CFU and 300 CFU and no
spreading colony growth, to count the aerobic plate count. For plates with less than 30
CFU, record the specific number of colonies; those with more than 300 CFU can be
recorded as incalculable.
6.3.3 When one of the plates has larger flaky colonies, it is not suitable to use it. The
plate without larger flaky colonies shall be used as the colony count of the degree of
dilution. If the flaky colonies are less than half of the plate, and the colonies in the
remaining half are evenly distributed, it is possible to calculate the number of the half
plate and multiply it by 2, to represent the number of colonies on one plate.
6.3.4 When there is a chain growth with no clear boundary between the colonies on the
plate, count each single chain as a colony.
7 Result and report
7.1 Calculation method of aerobic plate count
7.1.1 If the number of colonies on only one dilution plate is within the appropriate count
range, calculate the average of the number of colonies on the two plates; then multiply
the average by the corresponding dilution factor as the aerobic plate count per g (mL)
of the sample. Example is given in B.1.
7.1.2 If the number of colonies on the plate with two serial dilutions is within the
appropriate count range, calculate according to formula (1). For an example, see B.2.
Where:
N - The number of colonies in the sample;
ΣC - The sum of the colony counts on the plates (containing plates with appropriate
range of colony counts);
n1 - Number of plates at the first dilution (low dilution ratio);
n2 - Number of plates at the second dilution (high dilution ratio);
d - Dilution factor (first dilution).
7.1.3 If the number of colonies on all dilution plates is greater than 300 CFU, the plate
with the highest dilution shall be counted. The other plates can be recorded as
uncountable. The result shall be calculated by multiplying the average number of
colonies by the highest dilution ratio. For an example, see B.3.
7.1.4 If the plate colony count of all dilutions is less than 30 CFU, it shall be calculated
Appendix A
Medium and reagents
A.1 Plate count agar (PCA) medium
A.1.1 Ingredients
Tryptone (main nutrient): 5.0 g
Yeast extract (main nutrient): 2.5 g
Glucose (main nutrient): 1.0 g
Agar: 15.0 g
Distilled water: 1000 mL
A.1.2 Preparation method
Add the above ingredients to distilled water; boil to dissolve; adjust the pH to 7.0±0.2.
Dispense into suitable containers; sterilize by autoclaving at 121 °C for 15 min.
A.2 Sterile phosphate buffer
A.2.1 Ingredients
Potassium dihydrogen phosphate (KH2PO4): 34.0 g
Distilled water: 500 mL
A.2.2 Preparation method
Stock solution: Weigh 34.0 g of potassium dihydrogen phosphate and dissolve it in 500
mL of distilled water; use about 175 mL of 1 mol/L sodium hydroxide solution to adjust
the pH to 7.2; use distilled water to dilute to 1000 mL; store in the refrigerator.
Diluent: Take 1.25 mL of the stock solution; use distilled water to dilute to 1000 mL;
divide it into suitable containers; sterilize it by autoclaving at 121 °C for 15 min.
A.3 Sterile normal saline
A.3.1 Ingredients
Sodium chloride: 8.5 g
......
GB 4789.2-2016
GB
NATIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
Food safety national standard
Microbiological examination of
food hygiene-detection of aerobic bacterial count
ISSUED ON. DECEMBER 23, 2016
IMPLEMENTED ON. JUNE 23, 2017
Issued by. National Health and Family Planning Commission of People’s
Republic of China;
State Food and Drug Administration.
Table of contents
Foreword ... 3
1 Scope ... 4
2 Terms and definitions ... 4
3 Equipment and materials ... 4
4 Culture medium and reagents ... 5
5 Test procedures ... 5
6 Operating procedures ... 6
7 Results and reports ... 8
Appendix A Culture medium and reagents ... 11
Foreword
This standard replaces GB 4789.2-2010 “Food safety national standard -
Microbiological examination of food hygiene-detection of aerobic bacterial
count”.
Food safety national standard
Microbiological examination of
food hygiene-detection of aerobic bacterial count
1 Scope
This standard specifies the method of determination of the aerobic plate count
in food.
This standard applies to the determination of the aerobic plate count in food.
2 Terms and definitions
Aerobic plate count
It refers to the total number of microbial colonies formed per gram (mL) of the
sample after treatment and cultivation under certain conditions (such as culture
medium, culture temperature and incubation time).
3 Equipment and materials
In addition to conventional microbiological laboratory sterilization and culture
equipment, other equipment and materials are as follows.
3.1 Constant temperature incubator. 36 °C ± 1 °C, 3 0 °C ± 1 °C.
3.2 Refrigerator. 2 °C ~ 5 °C.
3.3 Constant temperature water bath. 4 6 °C ± 1 °C.
3.4 Balance. the sensitivity is 0.1 g.
3.5 Homogenizer.
3.6 Oscillator.
3.7 Sterile pipettes. 1mL (with 0.1 mL scale), 10 mL (with 0.1 mL scale) OR
micro pipettes and tips.
6.3.1 It may conduct observation through naked eyes; if necessary, USE a
magnifying glass or colony counter; RECORD the dilution and the
corresponding colony count. The colony count is expressed by the colony-
forming units (CFU).
6.3.2 SELECT the aerobic plate count for which the colony count is 30 CFU ~
300 CFU without the growth of dispersed colonies. RECORD the actual colony
count of the plate lower than 30 CFU; and RECORD those more than 300 CFU
as “too much to be counted”. The colony count of each dilution shall adopt the
average value of the two plates.
6.3.3 If one plate has larger platelet growth of colonies, it shall not be used;
BUT it shall use the plate without platelet growth of colonies as the colony count
of this dilution; if the platelet colony does not reach to half of the plate area AND
the colony distribution in another half is uniform, it may calculate the value of
the half plate AND multiple by 2 to represent the colony count of a whole plate.
6.3.4 When there is streaky growth between colonies with no apparent
boundaries on the plate, MAKE each single strand as a colony for counting.
7 Results and reports
7.1 Calculation methods of aerobic plate count
7.1.1 If there is only one plate on which the colony number is within the
appropriate counting range, CALCULATE the average value of the two aerobic
plate count, then MULTIPLE the average value by the corresponding dilution
factor, to obtain the aerobic plate count per gram (mL) of sample.
7.1.2 If there are two plate colony number of serial dilution fall into the
appropriate count range, it shall use the equation (1) to conduct calculation.
Where.
N - Number of colony in the sample;
ΣC - Sum of plate colony number (including the plate with appropriate range
of colony number);
n1 - First dilution (low dilution factor) plate number;
Sodium chloride. 8.5 g
Distilled water. 1000 mL
A.3.2 Preparation methods
WEIGH 8.5 g of sodium chloride and DISSOLVE it in 1000 mL of distilled water;
MAKE it subjected to 121 °C autoclaving for 15 min.
......
GB 4789.2-2010
NATIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard
Food Microbiological Examination.
Aerobic Plate Count
ISSUED ON. MARCH 26, 2010
IMPLEMENTED ON. JUNE, 1, 2010
Issued by. Ministry of Health of the People’s Republic of China
GB
Tips - GB 4789 Series (Not part of this Standard)
Standard ID Standard Name Issued Date
Enforced
Date New Version (Click to check)?
GB 4789.1-2010 National food safety standard Food microbiological examination. General guidelines 2010-03-26 2010-06-01
GB 4789.2-2010 National food safety standard Food microbiological examination. Aerobic plate count 2010-03-26 2010-06-01
GB 4789.3-2010 National food safety standard Food microbiological examination. Enumeration of coliforms 2010-03-26 2010-06-01
GB 4789.4-2010 National food safety standard Food microbiological examination. Salmonella 2010-03-26 2010-06-01
GB 4789.5-2012 National Food Safety Standard Microbiological Examination of Food Hygiene - Examination of Shigella 2012-05-17 2012-07-17
GB/T 4789.6-
Microbiological examination of food hygiene Examination of
diarrheogenic Escherichia coli 2003-08-11 2004-01-01
GB/T 4789.7-
Microbiological examination of food hygiene. Examination of
Vibrio parahaemolyticus 2008-05-16 2008-11-01
GB/T 4789.8-
Microbiological examination of food hygiene. Examination of
Yersinia enterocolitica 2008-11-21 2009-03-01
GB/T 4789.9-
Microbiological examination of food hygiene. Examination of
Campylobacter jejuni 2008-11-21 2009-03-01
GB 4789.10-2010 National food safety standard Food microbiological examination. Staphylococcus aureus 2008-11-21 2009-03-01
GB/T 4789.11-
Microbiological examination of food hygiene Examination of
streptococcus hemolyticus 2003-08-11 2004-01-01
GB/T 4789.12-
Microbiological examination of food hygiene Examination of
Clostridium botulinum and botulinus toxin 2003-08-11 2004-01-01
GB 4789.13-2012 National Food Safety Standard Microbiological Examination of Food Hygiene - Examination of Clostridium Perfringens 2012-05-17 2012-07-17
GB/T 4789.14-
Microbiological examination of food hygiene Examination of
Bacillus cereus 2003-08-11 2004-01-01
GB 4789.15-2010 National food safety standard Food microbiological examination. Enumeration of moulds and yeasts 2010-03-26 2010-06-01
GB/T 4789.16-
Microbiological examination of food hygiene Identification of
common mycotoxin producing fungi 2003-08-11 2004-01-01
GB/T 4789.17-
Microbiological examination of food hygiene Examination of
meat and meat products 2003-08-11 2004-01-01
GB 4789.18-2010 National food safety standard Food microbiological examination. Milk and milk products 2010-03-26 2010-06-01
GB/T 4789.19-
Microbiological examination of food hygiene Examination of
egg and egg products 2003-08-11 2004-01-01
GB/T 4789.20-
Microbiological examination of food hygiene Examination of
aquatic product foods 2003-08-11 2004-01-01
GB/T 4789.21-
Microbiological examination of food hygiene Examination of
frozen drinks and cold drinks 2003-08-11 2004-01-01
GB/T 4789.22-
Microbiological examination of food hygiene Examination of
flavourings 2003-08-11 2004-01-01
GB/T 4789.23-
Microbiological examination of food hygiene Examination of
cold dish and bean products 2003-08-11 2004-01-01
GB/T 4789.24-
Microbiological examination of food hygiene Examination of
candy, cake and preserved fruits 2003-08-11 2004-01-01
GB/T 4789.25-
Microbiological examination of food hygiene Examination of
wines 2003-08-11 2004-01-01
GB/T 4789.26-
Microbiological examination of food hygiene Examination of
commercial sterilization of canned food 2003-08-11 2004-01-01
GB/T 4789.27-
Microbiological examination of food hygiene. Examination of
residue of antibiotics in fresh milk 2008-11-21 2009-03-01
GB/T 4789.28-
Microbiological examination of food hygiene Staining
methods, culture mediums and reagents 2003-08-11 2004-01-01
GB/T 4789.29-
Microbiological examination of food hygiene Examination of
pseudomonas cocovenenans subsp. farinofermentans 2003-08-11 2004-01-01
GB 4789.30-2010 National food safety standard Food microbiological examination. Listeria monocytogenes 2010-03-26 2010-06-01
GB/T 4789.31-
Microbiological examination of food hygiene Examination of
salmonellae, shigellae, and diarrhoea causative Escherichia
coli by means of the diagnostic typing phage set for
enterobacteriaceae
GB/T 4789.32-
Microbiological examination for food hygiene rapid detection
of coliform bacteria 2002-06-13 2002-10-01
GB/T 4789.33-
Microbiological examination of food hygiene Examination of
cereal, fruit and vegetable 2003-08-11 2004-01-01
GB 4789.34-2012 National Food Safety Standard Microbiological Examination of Food Hygiene - Examination of Bifidobacterium 2012-05-17 2012-07-17
GB 4789.35-2010 National food safety standard Food microbiological examination. Lactic acid bacteria 2010-03-26 2010-06-01
GB/T 4789.36-
Microbiological examination of food hygiene. Examination of
Escherichia coli O157. H7/NM 2008-05-16 2008-11-01
GB/T 4789.37-
Microbiological examination of food hygiene. Examination of
Staphylococcus aureus 2008-11-21 2009-03-01
GB 4789.38-2012 National Food Safety Standard Microbiological Examination of Food Hygiene - Enumeration of Escherichia Coli 2012-05-17 2012-07-17
GB/T 4789.39-
Microbiological examination of food hygiene. Enumeration of
faecal coliforms 2008-11-21 2009-03-01
GB 4789.40-2010 National food safety standard Food microbiological examination. Enterobacter sakazakii 2010-03-26 2010-06-01
Table of Contents
Foreword ...7
1 Scope ...8
2 Terms and definitions ...8
3 Devices and materials ...8
4 Culture medium and reagents ...8
5 Examination procedure ...9
6 Operational procedure ...9
7 Result and reporting ... 11
Annex A ...14
Foreword
This Standard replaces GB/T 4789.2-2008 Microbiological Examination of Food Hygiene -
Aerobic Plate Count.
The main changes in this Standard over GB/T 4789.2-2008 are as follows.
- Modify the standard name of both English and Chinese;
- Modify the explanation of the calculation formula for aerobic plate count;
- Modify the culture medium and reagents;
- Delete the “second method - aerobic plate count PetrifilmTM test strip method”.
Annex A of this Standard is normative.
The historical editions replaced by this Standard are as follows.
- GB 4789.2-1984, GB 4789.2-1994, GB/T 4789.2-2003, and GB/T 4789.2-2008.
National food safety standard Food microbiological
examination. Aerobic plate count
1 Scope
This Standard specifies determination methods of aerobic plate count.
This Standard is applicable to the determination of aerobic plate count.
2 Terms and definitions
2.1 Aerobic plate count
It refers to the total number of microbes colonies formed in per g (mL) of testing
sample obtained from the food which is processed, and cultured (such as culture
medium, culture temperature and incubation time) under certain conditions.
3 Devices and materials
Except the conventional sterilization and culture devices of microbiological
laboratory, other devices and materials are as follows.
3.1 Thermostat incubator. 36 ºC ± 1 ºC, 30 ºC ± 1 ºC.
3.2 Refrigerator. 2 ºC.
3.3 Thermostat water bath. 46 ºC± 1 ºC.
3.4 Balance. sensitivity 0.1g.
3.5 Homogenizer.
3.6 Oscillator.
3.7 Sterile pipettes. 1 mL (accurate to 0.01 mL), 10 mL (accurate to 0.1 mL) or micro-
pipettes with sucking head.
3.8 Sterile conical flasks. 250 mL and 500 mL.
3.9 Sterile petri dish. 90 mm in diameter.
3.10 pH meter or pH cuvette tube or precision pH test paper.
3.11 Magnifier or/and colony counter.
4 Culture medium and reagents
medium (about 4 mL), after the solidification, reverse the petri dish and make
culture under the equal conditions specified in 6.2.1.
6 . 3 Colony count
Perform visual observation, use magnifier or colony counter (if necessary), and
record the dilution fold and the count of corresponding colonies. The colony count
is represented as colony-forming units (CFU).
6.3.1 Select the aerobic plates with the colony count ranging from 30 CFU to 300 CFU
and without diffused growth of colonies to calculate the total colony count. For the
plates lower than 30 CFU, record the exact colony number, and the plates with
more than 300 CFU can be recorded as “countless”. The colony count of each
dilution shall be the average of two plate counts.
6 . 3 . 2 If one of the plates has colonies growing in a comparatively large patch, it should
not be used and the other plate free of this problem shall be used for the colony
count of the corr...
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