评价平板法定量检测单增李斯特氏菌

Evaluation of quantitative detection of Listeria monocytogenes by plate method

中文关键词:  单增李斯特氏菌  平板法  培养基  接种方法

英文关键词:Listeria monocytogenes  plate method  medium  vaccination method

中文摘要:

      目的 评价平板法定量检测单增李斯特氏菌的效果。方法 选择市场常用的5种李斯特氏菌显色培养基和PALCAM琼脂培养基, 根据GB 4789.28—2013《食品卫生微生物学检验 染色法、培养基和试剂》评估培养基的质量和效果; 依据GB 4789.30—2016《食品安全国家标准 食品微生物学检验 单核细胞增生李斯特氏菌检验》进行单增李斯特氏菌平板计数, 通过配对t检验法分析6种培养基定量结果, 同时比较涂布法和倾注法2种接种方法的差异性。结果 市售的6种培养基半定量测试中, 目标菌的生长指数(growth index, G)≥6, 非目标菌G≤1, 质量符合标准检测要求; 统计分析显示6种培养基获得的单增李斯特氏菌计数结果无显著差异, 但显色培养基上的菌落分布均匀, 容易辨认, 效果优于PALCAM; 同时分析两种接种方法的检测结果, 发现涂布法和倾注法无显著性差异。结论 市售的6种培养基质量符合标准要求, 且对单增李斯特氏菌的计数结果具有较好的一致性, 涂布法和倾注法2种接种方法具有可交换性。

英文摘要:

      Objective To evaluate the quantitative detection of Listeria monocytogenes by the plate method. Methods Five commonly used Listeria chromogenic medium and PALCAM agar media on the market were selected, and their quality and effect were evaluated according to GB 4789.28—2013 Food hygienic microbiological examination of staining methods, media and reagents. Then the total number of colonies of Listeria monocytogenes with the 6 media was got according to GB 4789.30—2016 National food safety standard-Food microbiology inspection-Listeria monocytogenes test and the results were analyzed by the paired t test method. The differences between the coating method and the pouring method were compared. Results The growth index (G) of target bacteria was >6 and the growth index of non-target bacteria was <1 when the 6 commercially available media were tested, which proved their quality met the standard testing requirements. Statistical analysis showed that the counts of Listeria monocytogenes obtained from the 6 media were not significantly different. However, the chromogenic media were better than PALCAM because the colonies on the chromogenic media were evenly distributed and easy to identify. At the same time, it was found that the coating method and the pouring method were not significantly different by analyzing the test results of the 2 methods. Conclusion The quality of the 6 commercially available culture media meets the standard requirements and the counting results have good consistency. The coating method and pouring method are interchangeable.