GB 4789.35-2010 Food microbiological examination.Lactic acid bacteria
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F7E5433E12BD44B09E07D81C31C5B388 |
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0.41 |
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10 |
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日期： |
2024-6-23 |
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G昼,National Food Safety Standard of the People's Republic of China,GB4789.35-2010,National Food Safety Standard,Food microbiological examination:,Lactic acid bacteria,Issued by 2010-03-26 Implemented by 2010-06-01,issued by Ministry of Health of the People's Republic of China,GB 4789.35-2010,Preface,The Standard substitutes the GB/T 4789.35-2003 ^Microbiological Examination for Food Hygiene :,Examination of Lactic Acid Bacteria in Beverages Containing Lactic Acid Bacteria".,Compared with the GB/T4789.35-2008, main changes are following:,-The count methods of lactic acid bacteria, lactobacillus, bifidobacteria and streptococcus,thermophilus are revised.,The appendix A of the standard is the normative appendix.,The replaced former editions are:,-GB 4789.35-1996, GB/T 4789.35-2003, GB/T4789.35-2008,I,GB 4789.35-2010,National Food Safety Standard,Food microbiological examination: Lactic Acid Bacteria,1. Scope,The Standard defines the examination method of lactic acid bacteria in foods containing,lactic acid bacteria.,The Standard is applicable to the examination of lactic acid bacteria in foods containing live,lactic acid bacteria.,2. Normative References,The documents referred in the standard are requisite for the application of the standard.,For dated references, only the version dated is applicable to the standard.,For undated references, the latest version including all modification notices are applicable to,the standard.,3. Terms and Definitions,3.1 Lactic acid bacteria,The common name of a group of bacteria capable of fermenting saccharides to produce,large amount of lactic acid.,The lactic acid bacteria in the standard are mainly Lactobacillus, Bifidobacterium and,Streptococcus genus.,4. Equipment and Materials,In addition to conventional sterilization and cultivation equipment used in microbiological,laboratory, other equipment and materials needed are as follows:,4.1 Thermostatic Cultivator: 36回±1回.,4.2 Refrigerator: 2回.5回,4.3 Homogenizer and sterile homogenizing bag, homogenizing cup or sterile pestle.,4.4 Balance: accuracy of 0.1g.,4.5 Sterile tube: 18mmX180mm, 15mmX100mm,4.6 Sterile pipette: 1ml (with 0.01ml of scale), 10ml(with 0.1ml of scale) or micropipettor and,tips.,4.7 Sterile conical beaker: 500ml, 250ml,5. Culture Mediums and Reagents,5.1 MRS (man rogosa sharpe) Culture Medium and improved MRS with Li-Mupirocin Culture,Medium : refer to Appendix A.1.,5.2 MC (modified chalmers) Culture Medium: refer to Appendix A.2.,5.3 0.5% Sucrose Fermentation Tube: refer to Appendix A.3.,5.4 0.5% Cellobiose Fermentation Tube: refer to Appendix A.3.,5.5 0.5% Maltose Fermentation Tube: refer to Appendix A.3.,5.6 0.5% Mannite Fermentation Tube: refer to Appendix A.3.,5.7 0.5% Salicin Fermentation Tube: refer to Appendix A.3.,3,GB 4789.35 -2010,5.8 0.5% Sorbitol Fermentation Tube: refer to Appendix A.3.,5.9 0.5% Lactose Fermentation Tube: refer to Appendix A.3.,5.10 Aesculin Fermentation Tube: refer to Appendix A.4.,5.11 Gram's Staining Solution: refer to Appendix A.5.,5.12 Li-Mupirocin, chemically pure.,6. Examination Procedures,For the examination procedures of lactic acid bacteria, please refer to Fig. 1.,Figure 1. Examination Procedures of Lactic Acid Bacteria,7. Operation Procedures,7.1 Sample preparation,7.1.1 The whole process of sample preparation shall observe aseptic operation procedures.,7.1.2 Freezing samples shall be thawed at 2°C~5°C for no more than 18h, and it could also be,carried out at a temperature lower than 450C for no more than 15 min.,7.1.3 Solid and semi-solid food: measure 25g sample with aseptic operation into sterile,4,GB 4789.35-2010,homogenizing cup containing 225ml normal saline, homogenize at 8000-10000r/m for 1-2 min,and then formulate into 1:10 sample solution; or place it into sterile homogenizing bag,containing 225ml normal saline, beat with slaping type homogenizer for 1-2 min, and then,formulate into 1:10 sample solution.,7.1.4 Liquid sample: First, sufficiently shake the liquid samples, absorb 25ml sample solution,with sterile pipette into a sterile conical beaker containing 225ml normal saline (proper amount,of sterile beads are placed into the beaker in advance), and then shake up to formulate into 1:10,sample solution.,7.2 Procedures,7.2.1 Absorb 1ml 1:10 sample solution with 1ml sterile pipette or micropipettor, and place into a,sterile test tube containing 9ml normal saline along the wall of the tube (it is noted that the tip of,the pipette shall not touch the diluent), shake up the test tube or blow it repeatedly with,another piece of sterile pipette to homogeneity, and then formulate into 1:100 sample solution.,7.2.2 Get another 1m……
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