Food Science and Technology Ph.D. Program, Department of Agriculture, Food and Resource Sciences, University of Maryland Eastern Shore, 2116 Center for Food Science and Technology, Princess Anne, MD 21853, USA.
Food Microbiol. 2012 Sep;31(2):263-70. doi: 10.1016/j.fm.2012.03.015. Epub 2012 Apr 7.
Seven blue crab processing plants were sampled to determine the prevalence and sources of Listeria spp. and Listeria monocytogenes for two years (2006-2007). A total of 488 raw crabs, 624 cooked crab meat (crab meat) and 624 environmental samples were tested by standard methods. Presumptive Listeria spp. were isolated from 19.5% of raw crabs, 10.8% of crab meat, and 69.5% of environmental samples. L. monocytogenes was isolated from 4.5% of raw crabs, 0.2% of crab meat, and 2.1% of environmental samples. Ninety-seven percent of the isolates were resistant to at least one of the ten antibiotics tested. Eight different serotypes were found among 76 L. monocytogenes isolates tested with the most common being 4b, 1/2b and 1/2a. Automated EcoRI ribotyping differentiated 11 ribotypes among the 106 L. monocytogenes isolates. Based on ribotyping analysis, the distribution of the ribotypes in each processing plant had a unique contamination pattern. A total of 92 ApaI and 88 AscI pulsotypes among the 106 L. monocytogenes isolates were found and distinct pulsotypes were observed in raw crab, crab meat and environmental samples. Ribotypes and serotypes recovered from crab processing plants included subtypes that have been associated with listeriosis cases in other food outbreaks. Our findings suggest that molecular methods may provide critical information about sources of L. monocytogenes in crab processing plants and will augment efforts to improve food safety control strategies such as targeting specific sources of contamination and use of aggressive detergents prior to sanitizing.
对七家蓝蟹加工厂进行了两年（2006-2007 年）的采样，以确定李斯特菌属和单核细胞增生李斯特菌的流行率和来源。采用标准方法检测了 488 份生蟹、624 份熟蟹肉（蟹肉）和 624 份环境样本。从 19.5%的生蟹、10.8%的蟹肉和 69.5%的环境样本中分离出疑似李斯特菌属。从 4.5%的生蟹、0.2%的蟹肉和 2.1%的环境样本中分离出单核细胞增生李斯特菌。97%的分离株至少对 10 种抗生素中的一种具有耐药性。在对 76 株单核细胞增生李斯特菌分离株进行的 8 种不同血清型检测中，最常见的是 4b、1/2b 和 1/2a。106 株单核细胞增生李斯特菌分离株的自动 EcoRI 核糖体分型法区分出 11 种核糖体型。根据核糖体分型分析，每个加工厂的核糖体型分布具有独特的污染模式。在 106 株单核细胞增生李斯特菌分离株中发现了 92 种 ApaI 和 88 种 AscI 脉冲场凝胶电泳（PFGE）型，生蟹、蟹肉和环境样本中观察到不同的脉冲场凝胶电泳（PFGE）型。从蟹类加工厂回收的核糖体型和血清型包括与其他食品暴发李斯特菌病病例相关的亚型。我们的研究结果表明，分子方法可能提供有关蟹类加工厂单核细胞增生李斯特菌来源的关键信息，并将补充改善食品安全控制策略的努力，例如针对特定的污染来源和在消毒前使用刺激性清洁剂。
