Tortorello M L, Stewart D S
National Center for Food Safety and Technology, U.S. Food and Drug Administration, Summit-Argo, Illinois 60501.
Appl Environ Microbiol. 1994 Oct;60(10):3553-9. doi: 10.1128/aem.60.10.3553-3559.1994.
Artificially inoculated Escherichia coli O157:H7 was directly enumerated in ground beef and beef exudate, without enrichment or selection, by the antibody-direct epifluorescent filter technique (Ab-DEFT). The total assay time of the Ab-DEFT was less than 1 h. The beef was homogenized, treated for 15 min with trypsin and Triton X-100, and passed through a 5-microns-pore-size prefilter and then through a 0.2-microns-pore-size black polycarbonate filter. The final filter was stained directly with fluorescein-labeled anti-O157 polyclonal antibody, rinsed, and examined by epifluorescence microscopy. The sensitivity of the Ab-DEFT was compared with that of a standard enrichment culture technique. Both methods reliably determined the presence of the pathogen in beef at 16 CFU/g. The Ab-DEFT was also useful for quantifying the pathogen and monitoring its growth in beef.
通过抗体直接荧光过滤技术（Ab-DEFT），无需富集或筛选，直接对绞碎牛肉和牛肉渗出液中的人工接种大肠杆菌O157:H7进行计数。Ab-DEFT的总检测时间不到1小时。将牛肉均质化，用胰蛋白酶和吐温X-100处理15分钟，先通过孔径为5微米的预滤器，再通过孔径为0.2微米的黑色聚碳酸酯滤器。最后一个滤器直接用荧光素标记的抗O157多克隆抗体染色，冲洗后用落射荧光显微镜检查。将Ab-DEFT的灵敏度与标准富集培养技术的灵敏度进行比较。两种方法都能可靠地测定牛肉中每克含16个菌落形成单位（CFU）的病原体的存在情况。Ab-DEFT也可用于对病原体进行定量以及监测其在牛肉中的生长情况。
