混合培养法在检测食品中沙门氏菌中的应用评价

Evaluation of the application of mixed culture method in the detection of Salmonella spp.in foods

目的通过对标准菌株以及人工污染样品的检测,评价混合培养法在检测食品中沙门氏菌的应用。方法本研究采用混合培养法对3株不同血清型的沙门氏菌和30株非沙门氏菌进行检测,分析该方法的灵敏度和特异性;同时制备人工污染的样品(包括肉制品、乳制品、巧克力)进行检测,评价混合培养法和GB 4789.4—2016《食品安全国家标准食品微生物学检验沙门氏菌检验》方法的一致性。结果混合培养法对3株沙门氏菌的检出限为1 CFU/25 g,而30株非沙门氏菌检测结果均为未检出,说明该方法具有良好的特异性;用混合培养法和GB 4789.4—2016分别对人工污染样品进行检测,对3类加标样品的检测灵敏度为:100%、100%、100%,总体灵敏度为100%;检测特异性为:93.2%、97.8%、93.2%,总体特异性为94.7%;检测假阴性率为:0、0、0,总体假阴性率为0;假阳性率为:6.8%、2.2%、6.8%,总体假阳性率为:5.3%;相对准确度为:97%、99%、97%,总体相对准确度为97.7%;混合培养法与GB 4789.4—2016方法阳性比例显著性差异为:1.33、0、1.33,总体显著性差异为0.89。结论根据SN/T 3266—2012《食品微生物检验方法确认技术规范》的判定规则,混合培养法和GB 4789.4—2016在统计学意义上无显著性差异。该方法具有提高实验效率、降低检测成本的优势,能够快速检测食品中沙门氏菌,在食品中致病性微生物的检测中具有较好的推广性。

Objective To evaluate the application of mixed culture method in detecting Salmonella in food by detecting standard strains and artificially contaminated samples.Methods In this study,the mixed culture method was used to detect 3 Salmonella strains with different serotypes and 30 non-Salmonella strains to analyze the sensitivity and specificity of the method.At the same time,artificially contaminated samples(including meat products,dairy products,and chocolate)were prepared for detection to evaluate the consistency between the mixed culture method and the GB 4789.4—2016 National food safety standard-Food microbiological examination-Salmonella examination method.Results The limit of detection of the mixed culture method for 3 strains of Salmonella was 1 CFU/25 g,while the detection results of 30 non-Salmonella strains were all not detected,indicating that this method had good specificity.The artificially contaminated samples were detected by the mixed culture method and the GB 4789.4-2016 method respectively.The detection sensitivities of 3 types of spiked samples were:100%,100%,100%,and the overall sensitivity was 100%;the detection specificities were:93.2%,97.8%,93.2%,and the overall specificity was 94.7%;the detection false negative rates were:0,0,0,and the overall false negative rate was 0;the false positive rates were:6.8%,2.2%,6.8%,and the overall false positive rate was 5.3%;the relative accuracies were:97%,99%,97%,and the overall relative accuracy was 97.7%;the significant differences in positive proportions between the mixed culture method and the GB 4789.4-2016 method were:1.33,0,1.33,and the overall significant difference was 0.89.Conclusion According to the judgment rules of SN/T 3266-2012 Technical specifications for confirmation of food microbiological inspection methods,there is no significant difference between the mixed culture method and the GB 4789.4-2016 method in statistical significance.This method has the advantages of improving experimental efficiency and reducing detection costs.It can quickly detect Salmonella spp.in food and has good applicability in the detection of pathogenic microorganisms in food.