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GB/T 18204.3-2000 English PDF (GBT18204.3-2000)

GB/T 18204.3-2000 English PDF (GBT18204.3-2000)

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GB/T 18204.3-2000: Methods of microbiological examination for tea set in public places. Determination of coliform bacteria

This standard specifies the method for determination of coliform bacteria in tea sets in public places. This standard applies to the determination of coliform bacteria in public tea sets in public places.
GB/T 18204.3-2000
GB
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 13.020
C 51
Methods of microbiological examination for tea set in
public places - Determination of Coliform bacteria
ISSUED ON: SEPTEMBER 30, 2000
IMPLEMENTED ON: JANUARY 01, 2001
Issued by: State Bureau of Quality Technical Supervision
Abolished (Replaced by GB/T 18204.4-2013)
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Definition ... 4
3 Instruments ... 4
4 Medium and reagents ... 5
5 Testing procedures ... 7
6 Operation steps ... 8
7 Report of results ... 9
Methods of microbiological examination for tea set in
public places - Determination of Coliform bacteria
1 Scope
This standard specifies the method for determination of coliform bacteria in tea sets in public places.
This standard applies to the determination of coliform bacteria in public tea sets in public places.
2 Definition
This standard uses the following definition.
Coliform bacteria
Refers to a group of Gram-negative non-bacillus bacteria, that can ferment lactose, produce acid, produce gas, aerobic and facultative anaerobic, when cultured at 37 ??C for 24 hours.
The bacteria are mainly derived from human and animal feces, so it is used as an indicator of fecal pollution, to evaluate the sanitary quality of the test object. 3 Instruments
3.1 High-pressure steam sterilizer.
3.2 Dry heat sterilization box.
3.3 Incubator: 36 ??C ?? 1 ??C.
3.4 Water tank.
3.5 Electric stove.
3.6 Balance.
3.7 Sterilized plate: 9 cm in diameter.
3.8 Sterilized graduated straws: 1 mL, 10 mL.
3.9 Sterilized cotton swabs.
3.10 Sterilized scissors.
3.11 pH meter or precision pH test paper.
4 Medium and reagents
4.1 Lactose bile salt fermentation broth
4.1.1 Ingredients:
Peptone: 20 g
Porcine bile salt (or beef and sheep bile salt): 5 g
Lactose: 10 g
0.04% bromocresol purple aqueous solution: 25 mL
Distilled water: 1000 mL
4.1.2 Preparation method: Dissolve peptone, bile salt, lactose in distilled water. Adjust the pH to 7.4. Add bromocresol purple solution. Mix well. Dispense into test tubes, which are equipped with inverted tubes, 10 mL per tube. Autoclave at 115 ??C for 15 min.
Note: The double-material lactose bile salt fermentation tube has doubled other ingredients. except distilled water.
4.2 Eosin methylene blue agar
4.2.1 Ingredients:
Egg white: 10 g
Lactose: 10 g
Dipotassium hydrogen phosphate: 2 g
Agar: 17g
2% eosin aqueous solution: 20 mL
0.65% methylene blue solution: 10 mL
Distilled water: 1000 mL
4.2.2 Preparation method: Dissolve peptone, phosphate, agar in distilled water. 4.4.4 Safranine counterstaining solution:
Safranine: 0.25 g
95% ethanol: 10 mL
Distilled water: 90 mL
Dissolve safranine in ethanol. Then use distilled water to dilute it.
4.5 Staining method
4.5.1 Fix the smear on the flame. Add crystal violet staining solution dropwise. Stain for 1 min. Use water to wash it.
4.5.2 Add gram iodine solution dropwise. Let it act for 1 min. Use water to wash it.
4.5.3 Add 95% ethanol dropwise to decolorize, for about 30 s. Use water to wash it.
4.5.4 Add counterstain solution dropwise, to counterstain for 1 min. Use water to wash it. Wait for it to dry. Check with microscope.
4.6 Staining results
Gram-positive bacteria are purple; gram-negative bacteria are red.
4.7 Rapid test paper for coliform bacteria
4.7.1 Quality requirements: The paper must meet the quality standards for fast inspection of coliform bacteria for food (drinking) utensils.
4.7.2 Quality standard: Each piece of paper is 5 cm x 5 cm; the pH value is 7.0 ~ 7.4; the packaging is sterile. The manufacturer has been reviewed and approved by the health department.
5 Testing procedures
The testing procedure for coliform bacteria is as follows:

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