Bacterial pathogens in food processing: Studies of the survival and control of Listeria monocytogenes to enhance food safety

单核细胞增生李斯特菌是一种严重威胁食品安全的细菌性公害。细菌病原体可以在食品加工表面上持续很长一段时间，以增加污染食品的机会。加拿大人在2008年亲身经历了这种情况的危险，在安大略的一个加工设施中，食用受污染的午餐肉造成56例霍乱和22例死亡。最近，美国爆发的疫情震惊了消费者，23人（116例）死于食用来自科罗拉多的受污染新鲜哈密瓜。显然，我们需要更好的干预战略。 本研究计划的长期目标是阐明L.食品加工环境中的单核细胞增生。该计划将建立在我的实验室正在进行的工作。 具体的短期目标或研究问题，我的研究团队将在未来几年解决，如下： 1. L.的脱水耐性机制是什么？单核细胞增多症？ 2. 在长期的干燥过程中是否会产生耐干燥的亚群？ 3. 生物被膜的形成机制是什么，生物被膜对L.在存在或不存在竞争微生物的情况下，单核细胞增多症的生存和从低相对湿度的食品加工环境中去除？ 4. 细菌在不同环境条件下的脱水存活动力学是什么？ 当我们对L.通过研究单核细胞增多症的生存策略，我们的发现将导致制定应用研究项目，重点是开发改进的去除策略。换句话说，这项研究将有助于食品工业，改善卫生和食品加工战略，并为加拿大人提供更安全的食品。

Listeria monocytogenes is a serious bacterial hazard which threatens food safety. The bacterial pathogen can persist for extended periods of time on food processing surfaces to increase the chance of contaminating food products. Canadians experienced first hand the danger of this scenario in 2008, where consumption of contaminated luncheon meats from one processing facility in Ontario caused 56 cases of listeriosis and 22 deaths. Lately, an outbreak in the US has shocked consumers as 23 people (116 cases) have died from consuming contaminated fresh cantaloupe from Colorado. Clearly, we need better intervention strategies. The long term objective of the proposed research program is to elucidate the mechanisms responsible for the persistence of L. monocytogenes in the food processing environment. The proposed program will build on the on-going work in my laboratory. The specific short term objectives or research questions, which my research team will address in the coming years, are as follows: 1. What are the mechanisms of desiccation tolerance observed in L. monocytogenes? 2. Does a desiccation resistant subpopulation develop during long-term desiccation? 3. What are the mechanisms of biofilm formation and what role does biofilm play for L. monocytogenes' survival and removal from food processing environments with low RH in the presence or absence of competing microorganisms? 4. What is the kinetics of the bacterium's desiccation survival under different environmental conditions? As we gain a fundamental understanding of L. monocytogenes' survival strategies, our discoveries will lead to the formulation of applied research projects focused on developing improved removal strategies. In other words this research will help the food industry by leading to improved sanitation and food processing strategies as well as to safer food products for Canadians.