Kerdahi K F, Istafanos P F
U.S. Food and Drug Administration, Brooklyn, New York 11232, USA.
J AOAC Int. 1997 Sep-Oct;80(5):1139-42.
Two enzyme-linked immunoassay (ELISA) systems for rapid screening of Listeria spp. were compared for their use in analysis of spiked foods regulated by the U.S. Food and Drug Administration. The Tecra Listeria kit is a 48 h visual ELISA that detects Listeria spp. through colorimetry. It has been approved for first action by AOAC INTERNATIONAL. The Vitek immunodiagnostic assay system for Listeria (VIDAS LIS) is a fully automated 48 h ELISA that detects Listeria spp. by immunofluorescence. Fifty-two food samples were artificially contaminated with high (11-42 colony-forming units [cfu]/25 g food) and low (2-8 cfu/25 g food) levels of L. monocytogenes and screened by the 2 protocols. Unspiked samples were also assayed as negative controls. Six unspiked samples were found positive for Listeria spp. by both methods: 3 were identified as L. monocytogenes and 3 as L. innocua by official methods. Both ELISA methods detected all spiked samples. One unspiked sample was assayed positive by Tecra and negative by VIDAS LIS. No Listeria spp. were recovered when the sample was tested by the conventional method. No interference due to background fluorescence of food matrixes was observed in the VIDAS LIS method. Results suggest a modified VIDAS LIS preenrichment medium may be used in place of the VIDAS standard medium in the protocol.
比较了两种用于快速筛查李斯特菌属的酶联免疫吸附测定（ELISA）系统在分析美国食品药品监督管理局监管的加标食品中的应用。Tecra李斯特菌检测试剂盒是一种48小时可视ELISA，通过比色法检测李斯特菌属。它已被AOAC INTERNATIONAL批准为首次行动方法。Vitek李斯特菌免疫诊断测定系统（VIDAS LIS）是一种全自动48小时ELISA，通过免疫荧光检测李斯特菌属。52份食品样品被人工污染了高（11 - 42个菌落形成单位[cfu]/25克食品）和低（2 - 8 cfu/25克食品）水平的单核细胞增生李斯特菌，并通过这两种方法进行筛查。未加标的样品也作为阴性对照进行检测。两种方法均检测到6份未加标的样品为李斯特菌属阳性：通过官方方法鉴定其中3份为单核细胞增生李斯特菌，3份为无害李斯特菌。两种ELISA方法均检测到所有加标样品。一份未加标的样品经Tecra检测为阳性，经VIDAS LIS检测为阴性。当用传统方法检测该样品时，未检出李斯特菌属。在VIDAS LIS方法中未观察到食品基质背景荧光的干扰。结果表明，在该方法中可以使用改良的VIDAS LIS预增菌培养基代替VIDAS标准培养基。
