Hoffman A D, Wiedmann M
Department of Food Science, Cornell University, Ithaca, New York 14853, USA.
J Food Prot. 2001 Oct;64(10):1521-6. doi: 10.4315/0362-028x-64.10.1521.
Two commercial polymerase chain reaction (PCR)-based Listeria detection systems, the BAX for Screening/Listeria monocytogenes and the BAX for Screening/Genus Listeria, and a culture-based detection system, the Biosynth L. monocytogenes Detection System (LMDS), were evaluated for their ability to detect L. monocytogenes and Listeria spp. in raw ingredients and the processing environment. For detection of L. monocytogenes from raw fish, enrichment was performed in Listeria enrichment broth (LEB), followed by plating on both Oxford agar and LMDS L. monocytogenes plating medium (LMPM). Detection of Listeria and L. monocytogenes from environmental samples was performed using LMDS enrichment medium, followed by plating on both Oxford agar and LMPM. A total of 512 environmental samples and 315 raw fish were taken from two smoked fish processing facilities and screened using these molecular and cultural Listeria detection methods. The BAX for Screening/L monocytogenes was used to screen raw fish and was 84.8% sensitive and 100% specific. The BAX for Screening/Genus Listeria was evaluated on environmental samples and had 94.7% sensitivity and 97.4% specificity. In conjunction with enrichment in LEB, LMPM had a sensitivity and specificity for detection of L. monocytogenes from raw fish of 97.8 and 100%, respectively. Use of LMDS enrichment medium followed by plating on LMPM allowed for sensitivity and specificity rates of 94.8 and 100%, respectively, for detection of L. monocytogenes from environmental samples. We conclude that both the BAX systems and the use of LMPM allow for reliable and rapid detection of Listeria spp. and L. monocytogenes. While the BAX systems provide screening results in about 3 days, the use of LMPM allows for L. monocytogenes isolation in 4 to 5 days.
对两种基于聚合酶链反应（PCR）的商业化李斯特菌检测系统——用于筛查的BAX/单核细胞增生李斯特菌检测系统和用于筛查的BAX/李斯特菌属检测系统，以及一种基于培养的检测系统——生物合成单核细胞增生李斯特菌检测系统（LMDS），评估了它们在检测原料和加工环境中单核细胞增生李斯特菌及李斯特菌属的能力。为了从生鱼中检测单核细胞增生李斯特菌，先在李斯特菌增菌肉汤（LEB）中进行增菌，然后分别接种到牛津琼脂和LMDS单核细胞增生李斯特菌平板培养基（LMPM）上。从环境样本中检测李斯特菌和单核细胞增生李斯特菌时，使用LMDS增菌培养基，然后分别接种到牛津琼脂和LMPM上。从两家烟熏鱼加工设施共采集了512份环境样本和315份生鱼样本，并使用这些分子和培养的李斯特菌检测方法进行筛查。用于筛查的BAX/单核细胞增生李斯特菌检测系统用于筛查生鱼，其灵敏度为84.8%，特异性为100%。用于筛查的BAX/李斯特菌属检测系统在环境样本上进行评估，灵敏度为94.7%，特异性为97.4%。结合在LEB中增菌，LMPM检测生鱼中单核细胞增生李斯特菌的灵敏度和特异性分别为97.8%和100%。使用LMDS增菌培养基，然后接种到LMPM上，检测环境样本中单核细胞增生李斯特菌的灵敏度和特异性分别为94.8%和100%。我们得出结论，BAX系统和LMPM的使用都能可靠、快速地检测李斯特菌属和单核细胞增生李斯特菌。虽然BAX系统约3天就能提供筛查结果，但使用LMPM在4至5天内就能分离出单核细胞增生李斯特菌。
