GB 4789.14-2014 PDF English
US$115.00 · In stock · Download in 9 secondsGB 4789.14-2014: National food safety standard - Food Contact Materials and Articles - Food Microbiological Examination - Bacillus Cereus Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedureStatus: Valid GB 4789.14: Evolution and historical versions
| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivery | Name of Chinese Standard | Status |
| GB 4789.14-2014 | English | 115 |
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National food safety standard - Food Contact Materials and Articles - Food Microbiological Examination - Bacillus Cereus
| Valid |
| GB/T 4789.14-2003 | English | 239 |
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Microbiological examination of food hygiene -- Examination of Bacillus cereus
| Obsolete |
| GB 4789.14-1994 | English | RFQ |
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Microbiological examination of food hygiene. Examination of Bacillus cereus
| Obsolete |
| GB 4789.14-1984 | English | RFQ |
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3 days
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Microbiological examination of food hygiene--Examination of bacillus cereus
| Obsolete |
Excerpted PDFs (Download full copy in 9 seconds upon purchase)PDF Preview: GB 4789.14-2014
GB 4789.14-2014: National food safety standard - Food Contact Materials and Articles - Food Microbiological Examination - Bacillus Cereus
---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GB4789.14-2014
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard –
Food Microbiological Examination - Bacillus Cereus
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 Equipment and materials... 4
3 Culture media and reagents... 4
4 Plate count method of bacillus cereus (first method)... 5
5 MPN count method of bacillus cereus (second method)... 12
Annex A Culture media and reagents... 15
Annex B Retrieval table of bacillus cereus most probable numbers... 23
Foreword
This Standard replaces GB/T 4789.14-2003, Microbiological examination of food
hygiene - Examination of bacillus cereus.
Compared with GB/T 4789.14-2003, the major changes of this Standard are as follows.
-- it changes the Chinese name of the standard;
-- it adds the second method, the MPN counting method of bacillus cereus;
-- it changes the culture conditions for selective isolation medium (MYP), from
culturing for 12 h ~ 20 h at 37°C to culturing for 24 h ~ 48 h at 30°C ± 1°C;
-- it adds the lysozyme examination;
-- it changes the operating procedures;
-- it adds Annex A and Annex B.
National Food Safety Standard –
Food Microbiological Examination - Bacillus Cereus
1 Scope
This Standard specifies the examination method of bacillus cereus in food.
The first method of this Standard applies to the count of bacillus cereus in food which
has a high content of bacillus cereus; and the second method applies to the count of
bacillus cereus in food which has a low content of bacillus cereus.
2 Equipment and materials
In addition to conventional sterilization and culture equipment for microbiology
laboratories, the other equipment and materials are as follows.
a) refrigerators. 2°C ~ 5°C;
b) thermostatic incubators. 30°C ± 1°C, 36°C ± 1°C;
c) homogenizers;
d) electronic balances. sensitivity 0.1 g;
e) sterile conical flasks. 100 mL, 500 mL;
f) sterile pipettes. 1 mL (having 0.01 mL scale), 10 mL (having 0.1 mL scale) or
micropipettes and tips;
g) sterile plates. diameter 90 mm;
h) sterile examination tubes. 18 mm ×180 mm;
i) microscopes. 10× ~ 100× (oil immersion lens);
j) L spreader.
3 Culture media and reagents
3.1 Phosphate buffer solution (PBS). see A.1 of Annex A.
3.2 Mannitol yolk polymyxin (MYP) agar. see A.2 of Annex A.
3.3 Trypticase soy polymyxin broth. see A.3 of Annex A.
3.4 Nutrient agar medium. see A.4 of Annex A.
3.11 Motility medium. see A.11 of Annex A.
3.12 Sugar fermentation tube. see A.12 of Annex A.
3.13 V-P medium. see A.13 of Annex A.
4 Plate count method of bacillus cereus (first method)
4.1 Examination procedures
The examination procedures of the plate count method of bacillus cereus are as shown
in Figure 1.
4.2 Operating procedures
4.2.1 Sample treatment
Frozen samples shall be unfrozen not exceeding 15 min below 45°C and not exceeding
18 h at 2°C ~ 5°C. If they can’t be examined promptly, they shall be stored at - 10°C ~
-20°C. Non-frozen, perishable samples shall be examined as soon as possible; and if
they can’t be examined promptly, they shall be stored in a refrigerator at 2°C ~ 5°C
and examined within 24 h.
4.2.3 Sample dilution
Absorb 1 mL of the 1.10 sample homogeneous solution of 4.2.2 to add to a dilution
tube containing 9 mL of PBS or normal saline; fully mix up to make 1.100 sample
homogeneous solution. In accordance with the estimation of sample contamination
degree, operate as above and make into ten-fold incremental serial dilution sample
homogeneous solution in succession. After each dilution, replace one 1 mL sterile
pipette or tip.
4.2.5 Isolation and culture
4.2.5.1 Isolation
Under normal conditions, allow plates to stand for 10 min after applying. If sample
solution is difficult to absorb, it can be placed in an incubator to culture for 1 h at 30°C
± 1°C; turn over plates after sample homogeneous solution is evenly absorbed; place
them upside down in the incubator; culture for 24 h ± 2 h at 30°C ± 1°C. If the colonies
are not typical, continue culturing for 24 h ± 2 h before observing. On MYP agar plates,
typical colonies are of a faint pink colour (indicating unfermented mannitol) and there
are white to pale orchid pink precipitation ring (indicating the production of lecithinase).
4.3 Confirmatory appraisal
4.3.1 Dyeing microscopic examination
Pick single colonies of pure culture for Gram’s microscopic examination. Bacillus
cereus is Gram positive bacillus of size (1 μm ~ 1.3 μm) ×(3 μm ~ 5 μm); the spore is
oval which is located at the centre or one end of thallus, not expanding on thallus; both
ends of thallus are flat, normally arranged in the shape of short chains or long chains.
4.3.2 Biochemical identification
4.3.2.4 Root growth test
Item Bacillus cereus Bacillus thuringiensis Bacillus mycoides Bacillus anthracis Bacillus megaterium
4.3.2.6 Protein toxin crystal test
4.4 Calculation of results
4.4.1 Count and confirmation of typical colonies
4.4.1.1 Select plates having typical bacillus cereus colonies and plates of a total
colony count between 20 CFU ~ 200 CFU on three plates of the same dilution degree;
count typical colonies. In case of the phenomena of a) ~ f), calculate in accordance
with Equation (1) of 4.4.2.1.In case of the phenomenon of g), calculate in accordance
with Equation (2) of 4.4.2.2.
5 MPN count method of bacillus cereus (second method)
5.1 Examination procedures
The examination procedures of the MPN count method of bacillus cereus is shown in
Figure 2.
5.2 Operating procedures
5.2.1 Sample treatment
As in 4.2.1.
5.2.2 Sample preparation
As in 4.2.2.
5.2.3 Sample dilution
As in 4.2.3.
5.2.5 Culture
Use an inoculating loop to transfer 1 loop from each tube; inoculate on MYP agar plates
by streaking; culture for 24 h ± 2 h at 30°C ± 1°C. If colonies are not typical, continue
to culture for 24 h ± 2 h before observation.
5.2.6 Confirmatory appraisal
Select 5 typical colonies from each plate (select all if less than 5); inoculate them on
nutrient agar plates for pure culture by streaking; culture for 24 h ± 2 h at 30°C ± 1°C;
carry out confirmatory test. See 4.3.
Annex A
Culture media and reagents
A.1 Phosphate buffer solution (PBS)
A.1.1 Composition
Potassium dihydrogen phosphate 34.0 g
Distilled water 500.0 mL
A.3 Trypticase soy polymyxin broth
A.4 Nutrient agar
A.6 Motility medium
A.7 Nitrate broth
A.7.1 Ingredients
Peptone 5.0 g
Potassium nitrate 0.2 g
Distilled water 1,000.0 mL
A.8 Casein agar
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
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