GB 4789.30-2025 National food safety standard -Food microbiological examination -Examination of Listeria monocytogenes
1 Scope
This standard specifies the examination methods for Listeria monocytogenes in food.
Method I of this standard is applicable to the qualitative examination of Listeria monocytogenes in food. Method II is applicable to the enumeration of Listeria monocytogenes in foods with a high concentration of Listeria monocytogenes. Method III is applicable to the enumeration of Listeria monocytogenes in foods with a low concentration of Listeria monocytogenes.
2 Equipment and materials
In addition to conventional sterilization and incubation equipment used in microbiological laboratories, other equipment and materials required are as follows:
2.1 Refrigerator: 2℃~8℃.
2.2 Constant temperature incubators: 30℃±1℃, 36℃±1℃, and 25℃~30℃.
2.3 Homogenizer.
2.4 Microscope: 100×~1,000× magnification.
2.5 Electronic balances: With sensitivities of 0.1g and 0.1mg.
2.6 Conical flasks: 100mL and 500mL.
2.7 Aseptic pipettes: 1mL (graduated to 0.01mL), 10mL (graduated to 0.1mL), or pipettors (with volume ranges of 0.1mL, 1mL, and 10mL) and aseptic tips.
2.8 Aseptic culture dish: With a diameter of 90mm.
2.9 Aseptic test tubes: 16mm×160mm.
2.10 Centrifuge: 4,000r/min.
2.11 Aseptic centrifuge tube: 30mm×100mm.
2.12 Aseptic syringe: 1mL.
2.13 Oil immersion lens or phase contrast microscope.
2.14 Aseptic spreader.
2.15 Listeria monocytogenes ATCC 19111, CMCC 54004, or other equivalent strains.
2.16 Listeria innocua ATCC 33090 or other equivalent strains.
2.17 Listeria ivanovii ATCC 19119 or other equivalent strains.
2.18 Listeria seeligeri ATCC 35967 or other equivalent strains.
Foreword I
1 Scope
2 Equipment and materials
3 Culture media and reagents
4 Examination procedures
5 Operation steps
6 Results and report
7 Examination procedures
8 Operation steps
9 Results and report
10 Examination procedures
11 Operation steps
12 Results and report
Annex A Culture media and reagents
Annex B Retrieval table for the most probable number (MPN)of Listeria monocytogenes
