GB 4789.18-2010 English PDF

GB 4789.18-2010: National food safety standard -- Food microbiological examination: Milk and milk products
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GB 4789.18-2010
GB
National Standard
of the People’s Republic of China
National food safety standard
Food microbiological examination.
Milk and milk products
ISSUED ON. MARCH 26, 2010
IMPLEMENTED ON. JUNE 01, 2010
Issued by. Ministry of Health of the People’s Republic of China
Table of Contents
Forward ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Apparatus and materials ... 4 
4 Sampling program ... 5 
5 Treatment of test samples ... 6 
6 Test methods ... 8 
Forward 
This standard replaces GB/T 4789.18-2003 “Microbiological examination in food
hygiene-examination of milk and milk products“.
Compared with GB/T 4789.18-2003, the main changes of this standard are as
follows.
- Modify the Chinese and English names of t his standard.
- Modify the “Scope” and “Normative references”;
- Modify the sampling scheme and treatment method of various kinds of milk
products.
The previous versions replaced by t his standard are.
- GB 4789.18-1984, GB/T 4789.18-1994, GB/T 4789.18-2003.
National food safety standard
Food microbiological examination.
Milk and milk products
1 Scope 
This standard applies to microbiological examination of milk and milk products.
2 Normative references 
The following referenced documents are indispensable for the application of this
standard. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any
amendments) applies.
3 Apparatus and materials 
3.1 Sampling apparatus
Sampling apparatus shall use stainless steel or other appropriate materials. The
surface shall be smooth, without gap, with corner-rounded. The sampling
apparatus shall be cleaned and sterilized. Maintain dried prior to use. Sampling
apparatuses include stirring apparatus, sampling spoon, cutting wire, knife (lancet
or spatula), sampling drill, etc.
3.2 Sampling container
Sampling containers’ materials (such as glass, stainless steel, plastic, etc.) and its
structure shall guarantee the samples at its initial state. The container and cover
shall be cleaned, sterilized and dried. The capacity of the container shall have
adequate volume, so as to allow the sample to be sufficiently mixed before the test.
Sampling container includes sampling bag, sampling tube, and sampling bottle,
etc.
3.3 Other materials
Other materials include thermometers, aluminum foil, parafilm, marker pens,
sampling record forms, etc.
3.4 Materials for examination in lab
3.4.1 Materials for general examination shall be according to GB 4789.1.
3.4.2 Examination of microbial indicator bacteria shall be according to GB4789.1,
GB4789.3 and GB 4789.15 respectively.
3.4.3 Examination of pathogens shall be according to GB 4789.4, GB 4789.10, GB
4789.30, GB 4789.37, and GB 4789.40 respectively.
contains high level starch, it may use α-amylase to reduce the solution’s viscosity;
or double up the diluent so as to reduce the solution’s viscosity.
5.3.3 Casein and caseinate
Weigh 25 g of the test sample with aseptic technique. According to different
products, respectively add 225 mL of diluent such as sterilized physiological saline
or enrichment broth. When performing gradient dilution to the viscous sample
solution, it shall rinse the pipette aseptically for several times to transfer the
samples adhered to the inner wall of pipette to the solution as much as possible.
5.3.3.1 For casein that is produced by acidation process. Use dipotassium
hydrogen phosphate buffer and add defoamer to dissolve the sample at
pH8.4±0.2.
5.3.3.2 For casein that is produced by enzymatic curd’s process. Use dipotassium
hydrogen phosphate buffer and add defoamer to dissolve the sample under
condition of pH7.5±0.2. Stand for 15 min at room temperature. If necessary,
homogenize for 2 min in sterile homogenate bag. Then stand for another 5 min
before testing.
5.3.3.3 For caseinate. Use dipotassium hydrogen phosphate buffer to dissolve the
sample under condition of pH7.5±0.2.
6 Test methods 
6.1 Aerobic plate count. Test according to GB 4789.2.
6.2 Coliform. Count according to the direct counting method in GB 4789.3.
6.3 Salmonella. Test according to GB 4789.4.
6.4 Staphylococcus aureus. Test according to GB 4789.10.
6.5 Molds and yeasts. Count according to GB 4789.15.
6.6 Listeria monocytogenes bacteria. Test according to GB 4789.30.
6.7 Bifidobacterium. Test according to GB/T 4789.34.
6.8 Lactobacillus. Test according to GB/T 4789.35.
6.9 Enterobacter sakazakii. Test according to GB 4789.40.
GB 4789.18-2010
GB
National Standard
of the People’s Republic of China
National food safety standard
Food microbiological examination.
Milk and milk products
ISSUED ON. MARCH 26, 2010
IMPLEMENTED ON. JUNE 01, 2010
Issued by. Ministry of Health of the People’s Republic of China
Table of Contents
Forward ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Apparatus and materials ... 4 
4 Sampling program ... 5 
5 Treatment of test samples ... 6 
6 Test methods ... 8 
Forward 
This standard replaces GB/T 4789.18-2003 “Microbiological examination in food
hygiene-examination of milk and milk products“.
Compared with GB/T 4789.18-2003, the main changes of this standard are as
follows.
- Modify the Chinese and English names of t his standard.
- Modify the “Scope” and “Normative references”;
- Modify the sampling scheme and treatment method of various kinds of milk
products.
The previous versions replaced by t his standard are.
- GB 4789.18-1984, GB/T 4789.18-1994, GB/T 4789.18-2003.
National food safety standard
Food microbiological examination.
Milk and milk products
1 Scope 
This standard applies to microbiological examination of milk and milk products.
2 Normative references 
The following referenced documents are indispensable for the application of this
standard. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any
amendments) applies.
3 Apparatus and materials 
3.1 Sampling apparatus
Sampling apparatus shall use stainless steel or other appropriate materials. The
surface shall be smooth, without gap, with corner-rounded. The sampling
apparatus shall be cleaned and sterilized. Maintain dried prior to use. Sampling
apparatuses include stirring apparatus, sampling spoon, cutting wire, knife (lancet
or spatula), sampling drill, etc.
3.2 Sampling container
Sampling containers’ materials (such as glass, stainless steel, plastic, etc.) and its
structure shall guarantee the samples at its initial state. The container and cover
shall be cleaned, sterilized and dried. The capacity of the container shall have
adequate volume, so as to allow the sample to be sufficiently mixed before the test.
Sampling container includes sampling bag, sampling tube, and sampling bottle,
etc.
3.3 Other materials
Other materials include thermometers, aluminum foil, parafilm, marker pens,
sampling record forms, etc.
3.4 Materials for examination in lab
3.4.1 Materials for general examination shall be according to GB 4789.1.
3.4.2 Examination of microbial indicator bacteria shall be according to GB4789.1,
GB4789.3 and GB 4789.15 respectively.
3.4.3 Examination of pathogens shall be according to GB 4789.4, GB 4789.10, GB
4789.30, GB 4789.37, and GB 4789.40 respectively.
contains high level starch, it may use α-amylase to reduce the solution’s viscosity;
or double up the diluent so as to reduce the solution’s viscosity.
5.3.3 Casein and caseinate
Weigh 25 g of the test sample with aseptic technique. According to different
products, respectively add 225 mL of diluent such as sterilized physiological saline
or enrichment broth. When performing gradient dilution to the viscous sample
solution, it shall rinse the pipette aseptically for several times to transfer the
samples adhered to the inner wall of pipette to the solution as much as possible.
5.3.3.1 For casein that is produced by acidation process. Use dipotassium
hydrogen phosphate buffer and add defoamer to dissolve the sample at
pH8.4±0.2.
5.3.3.2 For casein that is produced by enzymatic curd’s process. Use dipotassium
hydrogen phosphate buffer and add defoamer to dissolve the sample under
condition of pH7.5±0.2. Stand for 15 min at room temperature. If necessary,
homogenize for 2 min in sterile homogenate bag. Then stand for another 5 min
before testing.
5.3.3.3 For caseinate. Use dipotassium hydrogen phosphate buffer to dissolve the
sample under condition of pH7.5±0.2.
6 Test methods 
6.1 Aerobic plate count. Test according to GB 4789.2.
6.2 Coliform. Count according to the direct counting method in GB 4789.3.
6.3 Salmonella. Test according to GB 4789.4.
6.4 Staphylococcus aureus. Test according to GB 4789.10.
6.5 Molds and yeasts. Count according to GB 4789.15.
6.6 Listeria monocytogenes bacteria. Test according to GB 4789.30.
6.7 Bifidobacterium. Test according to GB/T 4789.34.
6.8 Lactobacillus. Test according to GB/T 4789.35.
6.9 Enterobacter sakazakii. Test according to GB 4789.40.