Department of Food Science, Cornell University, Ithaca, New York 14853, USA.
J Food Prot. 2013 May;76(5):874-8. doi: 10.4315/0362-028X.JFP-12-552.
There is a continued need to develop improved rapid methods for detection of foodborne pathogens. The aim of this project was to evaluate the 3M Molecular Detection System (3M MDS), which uses isothermal DNA amplification, and the 3M Molecular Detection Assay Listeria using environmental samples obtained from retail delicatessens and meat, seafood, and dairy processing plants. Environmental sponge samples were tested for Listeria with the 3M MDS after 22 and 48 h of enrichment in 3M Modified Listeria Recovery Broth (3M mLRB); enrichments were also used for cultural detection of Listeria spp. Among 391 samples tested for Listeria, 74 were positive by both the 3M MDS and the cultural method, 310 were negative by both methods, 2 were positive by the 3M MDS and negative by the cultural method, and one sample was negative by the 3M MDS and positive by the cultural method. Four samples were removed from the sample set, prior to statistical analyses, due to potential cross-contamination during testing. Listeria isolates from positive samples represented L. monocytogenes, L. innocua, L. welshimeri, and L. seeligeri. Overall, the 3M MDS and culture-based detection after enrichment in 3M mLRB did not differ significantly (P < 0.05) with regard to the number of positive samples, when chi-square analyses were performed for (i) number of positive samples after 22 h, (ii) number of positive samples after 48 h, and (iii) number of positive samples after 22 and/or 48 h of enrichment in 3M mLRB. Among 288 sampling sites that were tested with duplicate sponges, 67 each tested positive with the 3M MDS and the traditional U.S. Food and Drug Administration Bacteriological Analytical Manual method, further supporting that the 3M MDS performs equivalently to traditional methods when used with environmental sponge samples.
仍然需要开发改进的快速方法来检测食源性病原体。本项目的目的是评估 3M 分子检测系统（3M MDS），该系统使用等温 DNA 扩增，以及 3M 分子检测李斯特菌检测试剂盒，用于从零售熟食店和肉类、海鲜和乳制品加工厂采集的环境样本。用 3M 改良李斯特菌回收肉汤（3M mLRB）对环境海绵样本进行 22 和 48 小时富集后，用 3M MDS 检测李斯特菌；富集物也用于李斯特菌属的文化检测。在 391 个测试李斯特菌的样本中，74 个样本 3M MDS 和文化方法均为阳性，310 个样本两种方法均为阴性，2 个样本 3M MDS 阳性而文化方法阴性，1 个样本 3M MDS 阴性而文化方法阳性。在进行统计分析之前，由于测试过程中存在潜在的交叉污染，从样本集中剔除了 4 个样本。阳性样本中的李斯特菌分离株代表单核细胞增生李斯特菌、无害李斯特菌、威氏李斯特菌和海氏李斯特菌。总体而言，当对 22 小时后阳性样本数、48 小时后阳性样本数和 22 和/或 48 小时 3M mLRB 富集后阳性样本数进行卡方分析时，3M MDS 和基于培养的检测在阳性样本数方面没有显著差异（P<0.05）。在使用 288 个带有重复海绵的采样点进行测试的情况下，每个采样点各有 67 个样本用 3M MDS 和美国食品和药物管理局传统的细菌分析手册方法检测为阳性，进一步支持 3M MDS 在与环境海绵样本一起使用时与传统方法等效。
