McIntyre Lorraine, Wilcott Lynn, Naus Monika
Environmental Health Services, BC Centre for Disease Control, 655 West 12th Avenue, Vancouver, BC, Canada V5Z 4R4.
Immunization Programs and Vaccine Preventable Diseases Services, BC Centre for Disease Control, 655 West 12th Avenue, Vancouver, BC, Canada V5Z 4R4 ; School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada V6T 1Z9.
Biomed Res Int. 2015;2015:131623. doi: 10.1155/2015/131623. Epub 2015 Mar 30.
Soft ripened cheese (SRC) caused over 130 foodborne illnesses in British Columbia (BC), Canada, during two separate listeriosis outbreaks. Multiple agencies investigated the events that lead to cheese contamination with Listeria monocytogenes (L.m.), an environmentally ubiquitous foodborne pathogen. In both outbreaks pasteurized milk and the pasteurization process were ruled out as sources of contamination. In outbreak A, environmental transmission of L.m. likely occurred from farm animals to personnel to culture solutions used during cheese production. In outbreak B, birds were identified as likely contaminating the dairy plant's water supply and cheese during the curd-washing step. Issues noted during outbreak A included the risks of operating a dairy plant in a farm environment, potential for transfer of L.m. from the farm environment to the plant via shared toilet facilities, failure to clean and sanitize culture spray bottles, and cross-contamination during cheese aging. L.m. contamination in outbreak B was traced to wild swallows defecating in the plant's open cistern water reservoir and a multibarrier failure in the water disinfection system. These outbreaks led to enhanced inspection and surveillance of cheese plants, test and release programs for all SRC manufactured in BC, improvements in plant design and prevention programs, and reduced listeriosis incidence.
在加拿大不列颠哥伦比亚省（BC）发生的两起单独的李斯特菌病疫情中，软质成熟奶酪（SRC）导致了130多起食源性疾病。多个机构对导致奶酪被单核细胞增生李斯特菌（L.m.）污染的事件展开了调查，该病菌是一种在环境中普遍存在的食源性病原体。在这两起疫情中，巴氏杀菌牛奶和巴氏杀菌过程均被排除为污染源。在疫情A中，L.m.的环境传播可能是从农场动物传播到人员，再传播到奶酪生产过程中使用的培养液。在疫情B中，鸟类被确定为可能在凝乳清洗步骤中污染了乳制品厂的供水和奶酪。疫情A中发现的问题包括在农场环境中运营乳制品厂的风险、L.m.通过共用厕所设施从农场环境转移到工厂的可能性、未能清洁和消毒培养喷雾瓶以及奶酪陈化过程中的交叉污染。疫情B中的L.m.污染可追溯到野生燕子在工厂的开放式蓄水池中排便以及水消毒系统的多重屏障故障。这些疫情促使加强了对奶酪厂的检查和监测、对BC省生产的所有SRC实施检测和放行计划、改进工厂设计和预防计划，并降低了李斯特菌病的发病率。
