Hitachi Chemical Research Center, Inc, Irvine, California 92617, USA.
J Food Prot. 2012 Sep;75(9):1603-10. doi: 10.4315/0362-028X.JFP-12-039.
Conventional foodborne pathogen assays currently used in the food industry often require long culture enrichments to increase pathogen levels so they can be detected. Even using sensitive real-time PCR assays, culture enrichment at least overnight is necessary especially for detection of pathogens with slow growth rates such as Listeria monocytogenes. To eliminate this cumbersome enrichment step and detect minute amounts of pathogens within 1 day, filter-based pathogen enrichment technology was developed utilizing a unique combination of glass fiber depth filter and porous filter aid materials to efficiently separate pathogens from food homogenates and avoid filter clogging by food particles. After pathogen immobilization in depth filters, only viable pathogens were selectively collected in a small volume of growth medium via microbial multiplication and migration; nonviable pathogens remained inside the filters. By assaying viable pathogens using real-time PCRs, multiple species of foodborne pathogens were detected, including L. monocytogenes, Salmonella enterica, and Escherichia coli O157:H7, at around 1 CFU/ml or 1 CFU/g in various food samples. This filter-based pathogen enrichment technology is a unique bacterial enrichment alternative to the conventional culture enrichment step and can significantly shorten the time necessary to obtain assay results.
传统的食品病原体检测方法通常需要长时间的培养富集来提高病原体水平，以便进行检测。即使使用灵敏的实时 PCR 检测方法，也至少需要过夜的培养富集，特别是对于生长缓慢的病原体的检测，如单核细胞增生李斯特菌。为了消除这种繁琐的富集步骤，并在 1 天内检测到微量的病原体，开发了基于过滤的病原体富集技术，该技术利用独特的玻璃纤维深度过滤器和多孔过滤助剂材料的组合，从食品匀浆中有效地分离病原体，并避免食物颗粒堵塞过滤器。在深度过滤器中固定病原体后，仅通过微生物增殖和迁移，就可以选择性地从小体积的生长培养基中收集有活力的病原体；无活力的病原体则留在过滤器内。通过实时 PCR 检测有活力的病原体，可以在各种食品样本中检测到包括单核细胞增生李斯特菌、肠炎沙门氏菌和大肠杆菌 O157:H7 等多种食源性病原体，其浓度约为 1 CFU/ml 或 1 CFU/g。这种基于过滤的病原体富集技术是传统培养富集步骤的一种独特的细菌富集替代方法，可以显著缩短获得检测结果所需的时间。
