Bureau of Microbial Hazards, Food Directorate, Health Canada, 251 Sir Frederick Banting Driveway, Ottawa, Ontario, Canada K1A 0K9.
J Food Prot. 2020 Aug 1;83(8):1444-1462. doi: 10.4315/JFP-20-029.
Foodborne diseases are a major cause of illness in Canada. One of the main pathogens causing cases and outbreaks of foodborne illness in Canada is Escherichia coli O157:H7. From 2008 to 2018, 11 outbreaks of E. coli O157:H7 infection in Canada were linked to leafy greens, including 7 (63.6%) linked to romaine lettuce, 2 (18.2%) linked to iceberg lettuce, and 2 (18.2%) linked to other or unspecified types of leafy greens. The consumption of lettuce in Canada, the behavior of E. coli O157:H7 on lettuce leaves, and the production practices used for romaine and iceberg lettuce do not seem to explain why a higher number of outbreaks of E. coli O157:H7 infection were linked to romaine than to iceberg lettuce. However, the difference in the shape of iceberg and romaine lettuce heads could be an important factor. Among the seven outbreaks linked to romaine lettuce in Canada between 2008 and 2018, an eastern distribution of cases was observed. Cases from western provinces were reported only twice. The consumption of romaine and iceberg lettuce by the Canadian population does not seem to explain the eastern distribution of cases observed, but the commercial distribution, travel distances, and the storage practices used for lettuce may be important factors. In the past 10 years, the majority of the outbreaks of E. coli O157:H7 infection linked to romaine lettuce occurred during the spring (March to June) and fall (September to December). The timing of these outbreaks may be explained by the availability of lettuce in Canada, the growing region transition periods in the United States, and the seasonality in the prevalence of E. coli O157:H7. The consumption of romaine lettuce by the Canadian population does not explain the timing of the outbreaks observed.
食源性疾病是加拿大的主要致病原因之一。引起加拿大食源性疾病病例和暴发的主要病原体之一是大肠杆菌 O157:H7。2008 年至 2018 年，加拿大发生了 11 起大肠杆菌 O157:H7 感染暴发事件，与叶类蔬菜有关，其中 7 起（63.6%）与罗马生菜有关，2 起（18.2%）与冰山生菜有关，2 起（18.2%）与其他或未指明类型的叶类蔬菜有关。加拿大生菜的消费、大肠杆菌 O157:H7 在生菜叶上的行为以及罗马生菜和冰山生菜的生产实践似乎并不能解释为什么与冰山生菜相比，与罗马生菜有关的大肠杆菌 O157:H7 感染暴发数量更多。然而，冰山和罗马生菜头的形状差异可能是一个重要因素。在 2008 年至 2018 年期间加拿大与罗马生菜有关的 7 起暴发事件中，观察到病例呈东部分布。仅报告了来自西部省份的 2 例病例。加拿大人口对罗马生菜和冰山生菜的消费似乎并不能解释观察到的病例东部分布，但生菜的商业分布、旅行距离和储存方式可能是重要因素。在过去 10 年中，与罗马生菜有关的大肠杆菌 O157:H7 感染暴发事件大多发生在春季（3 月至 6 月）和秋季（9 月至 12 月）。这些暴发事件的时间可能与加拿大生菜的供应情况、美国种植地区的过渡时期以及大肠杆菌 O157:H7 的季节性流行情况有关。加拿大人口对罗马生菜的消费并不能解释观察到的暴发时间。
