GB 4789.34-2016 PDF EnglishUS$85.00 · In stock · Download in 9 seconds
GB 4789.34-2016: National food safety standard - Food Microbiological Examination - Examination of Bifidobacterium Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedure Status: Valid GB 4789.34: Historical versions
Similar standardsGB 4789.34-2016: National food safety standard - Food Microbiological Examination - Examination of Bifidobacterium---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/GB4789.34-2016 GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA National Food Safety Standard - Food Microbiological Examination - Examination of Bifidobacterium Issued on. DECEMBER 23, 2016 Implemented on. JUNE 23, 2017 Issued by. National Health and Family Planning Commission of the People 's Republic of China; China Food and Drug Administration. Table of ContentsForeword... 3 1 Scope... 4 2 Equipment and materials... 4 3 Medium and reagent... 4 4 Inspection procedures... 5 5 Operation steps... 6 Annex A Medium and reagent... 12 Annex B Detection of organic acid metabolites of Bifidobacterium... 14ForewordThis Standard replaces GB 4789.34-2012 National Food Safety Standard - Food Microbiological Examination - Identification of Bifidobacterium. Compared with GB 4789.34-2012, the main changes in this Standard are as follows. - added the counting method for Bifidobacterium; - added MRS medium; - modified the application scope of this Standard; - modified Annex B as optional. National Food Safety Standard - Food Microbiological Examination - Examination of Bifidobacterium1 ScopeThis Standard specifies the identification and counting method for Bifidobacterium. This Standard applies to the identification and counting of pure bacteria strain of Bifidobacterium. This Standard applies to the identification of bacteria when the food only contains single Bifidobacterium. This Standard applies to the counting when the food only contains Bifidobacterium, i.e., the food may contain one or more different Bifidobacterium species.2 Equipment and materialsIn addition to microbial laboratory routine sterilization and training equipment, other equipment and materials are as follows. 2.1 Constant temperature incubator. 36°C ± 1°C. 2.2 Refrigerator. 2°C ~ 5°C. 2.5 Sterile pipettes. 1mL (with 0.01mL scale), 10mL (with 0.1mL scale) or micro-pipettes (200μL ~ 1000μL) and matching tips. 2.6 Sterile petri dish. 90 mm in diameter.3 Medium and reagent3.1 Bifidobacterium culture medium. see A.1. 3.2 PYG medium. see A.2. 3.6 Sulfuric acid. analytically pure. 3.7 Sulfuric acid. analytically pure. 3.8 Lactic acid. analytically pure.4 Inspection proceduresBifidobacterium inspection procedures are shown in Figure 1.5 Operation steps5.1 Sterile requirements All operating procedures shall follow the sterile procedures. 5.2 Identification of Bifidobacterium 5.2.1 Pure bacteria species 5.2.2 Food sample 5.2.2.1 Sample processing. take 25.0g (mL) of sample into a sterile conical flask or homogeneous bag containing 225.0mL of physiological saline, homogenizing at 8000r/min ~ 10000r/min for 1min ~ 2min or using slapping homogenizer to beat 1min ~ 2min to make 1.10 sample homogenizing solution. 5.2.3 Identification of bacteria 5.2.3.1 Smear microscopy. pick up Bifidobacterium single colony growing in Bifidobacterium plate or MRS plate for dyeing. Bifidobacterium is Gram-positive, short rod-shaped, slender rod-shaped or spherical, can form a variety of branches or bifurcation and other forms, non-acid, no spores, no power. 5.3 Counting of Bifidobacterium 5.3.1 Pure bacteria species 5.3.1.1 Preparation of solid and semi - solid samples. weigh aseptically 2.0g of sample; place into a sterile homogeneous cup containing 198.0mL of diluent, homogenizing at 8000r/min ~ 10000r/min for 1min ~ 2min, OR place in a sterile homogeneous bag containing 198.0mL of diluent; 5.3.2 Food sample 5.3.4 Colony counting 5.3.4.1 It can be observed with the naked eye, if necessary, with a magnifying glass or colony counter. Record the dilution factor and the corresponding number of colonies. The colony counting is expressed in colony-forming units (CFU). 5.3.5 Result representation 5.3.5.1 If the number of colonies on a dilution plate is within the appropriate counting range, calculate the average of the two plate colonies and multiply the average by the corresponding dilution factor as the total number of colonies per gram or milliliter. 5.3.5.2 If there are two consecutive dilutions of the number of plate colonies in the appropriate counting range, it shall calculate according to equation (1). 5.3.6 Report of the number of colonies 5.4 Results and report According to the results of 5.2.3.1, 5.2.3.2, 5.2.3.3, the species name of Bifidobacterium shall be reported. Issue the report according to the results of 5.3.6 colony counting, in CFU/g (mL).Annex AMedium and reagent A.1 Bifidobacterium agar medium A.1.1 Ingredients A.1.2 Preparation A.2 PYG liquid medium A.2.1 Composition Peptone 10.0 g Glucose 2.5 g Yeast 5.0 g Cysteine-HCl 0.25 g Salt solution 20.0 mL Vitamin K1 solution 0.5 mL Hemoglobin solution 5 mg/mL 2.5 mL Adding distilled water to 500.0 mL A.2.2 Preparation A.3 MRS medium A.3.1 Composition A.3.2 Preparation Add all components of A.3.1 to distilled water, dissolve by heating, calibrate to pH 6.2 ± 0.1, autoclave at 121°C for 15min ~ 20min after sub-packaging.Annex BDetection of organic acid metabolites of Bifidobacterium B.1 Preparation of Bifidobacterium culture medium Inoculate the Bifidobacterium cultured on Bifidobacterium agar plate or MRS agar plate into PYG liquid medium. Then use non-inoculated PYG liquid medium for blank control, anaerobic, culture at 36°C ± 1°C for 48h. B.2 Preparation of standard solution B.3 Method B.3.1 Treatment of acetic acid Take 2.0ml ~ 3.0mL of Bifidobacterium culture medium into 10mL centrifuge tube, add 0.2mL of 50% sulfuric acid solution (volume fraction), mix, add 2.0mL of acetone, mix and add excess sodium chloride, shake for 1min, then add 2.0mL of ether, shake for 1min, centrifuge at 3000 r/min for 5min. B.3.2 Treatment of lactic acid Take 2.0mL ~ 3.0mL of Bifidobacterium culture medium into 10mL colorimetric tube, place in a 100°C water bath for 10min, add 0.2mL of 50% (volume fraction) sulfuric acid solution, mix, add 1.0mL of methanol, place in a 58°C water bath for 30min. Add 1.0 mL of water, add 1.0 mL of chloroform, shake 3min, centrifuge at 3000 r/min for 5min, take chloroform layer for analysis. Use same operation steps for lactic acid standard and blank culture medium. B.3.3 Liquid chromatography conditions Chromatographic column. ZorbaxSb-Aq liquid chromatography column (4.6 x 150 mm, 5 µm) or other equivalent column; mobile phase. 20 mmol/L sodium dihydrogen phosphate solution (pH 2.0) - acetonitrile (99+1), isocratic elution at a flow rate of 1 mL/min; column oven. 35°C; UV detection wavelength. 210nm; external standard quantitative. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al. Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of English version of GB 4789.34-2016 be delivered?Answer: The full copy PDF of English version of GB 4789.34-2016 can be downloaded in 9 seconds, and it will also be emailed to you in 9 seconds (double mechanisms to ensure the delivery reliably), with PDF-invoice.Question 2: Can I share the purchased PDF of GB 4789.34-2016_English with my colleagues?Answer: Yes. 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