应用干制培养基检测食品中金黄色葡萄球菌

Detection of Staphylococcus aureus in food by dry culture medium

目的建立金黄色葡萄球菌X干制培养基(Staphylococcus aureus X medium, XSA)检测食品中金黄色葡萄球菌的分析方法。方法依据GB 4789.10—2016《食品安全国家标准食品微生物学检验金黄色葡萄球菌检验》中前处理的方法制备样品,将样品添加到7.5%NaCl肉汤增菌后接种至干制培养基XSA上进行培养,通过鉴定实验进行定性检测和菌落平板计数进行定量检测,并用国标法同时进行定性及定量检测。结果在定性检测方面,该方法和国标方法假阴性率和假阳性率均为0%,但是检测时间由92 h缩短为48 h,在定量检测方面,该方法与国标法的对数偏差值的绝对值为0.3979<0.45,并且在6次检测同一个样品时的结果相对标准偏差较小,从而说明该方法和国标法的准确度相当,检测时长由78h缩短至24h,大大提高了检验效率。结论该方法操作简便快捷,结果稳定,适用于食品中金黄色葡萄球菌的检测。

Objective To establish a method for the detection of Staphylococcus aureus in food by dried culture medium XSA. Methods Samples were prepared according to GB 4789.10—2016 National food safety standard-Food microbiology test-Staphylococcus aureus, after adding 7.5% NaCl broth, the samples were inoculated on a dry medium XSA for culture, and then qualitative test and quantitative detection were conducted by identification experiment and colony plate count respectively, and qualitative and quantitative detection were conducted by national standard method at the same time. Results In terms of qualitative detection, the false negative rate and false positive rate of this method and national standard method were 0%, but the detection time was shortened from 92 h to 48 h. In terms of quantitative detection, the absolute value of logarithmic deviation value of this method and national standard method was 0.3979<0.45. In addition, the relative standard deviation of the results of the same sample was smaller than that of the national standard method, which showed that the accuracy of the method was equivalent to that of the national standard method.The detection time was shortened from 78 h to 24 h, which greatly improved the inspection efficiency. Conclusion This method is simple, rapid and stable, which is suitable for the detection of Staphylococcus aureus in food.