Strategies to Enhance Food Safety: Characterization of Microcins and Bacteriophages

从健康和经济的角度来看，控制食品中细菌污染的能力具有极其重要的意义。大肠2012年秋季，XL食品公司（布鲁克斯，阿尔伯塔）爆发了O157：H7大肠杆菌疫情，导致加拿大有史以来最大规模的食品召回。虽然没有死亡与这次爆发有关，但经济影响是惊人的。2011年，一个类似的E.欧洲爆发的大肠杆菌疫情造成数千人感染，近50人死亡。虽然食品安全显然是一个主要的全球性问题，但在食品中添加化学添加剂也受到审查。公共部门对更天然和最低限度加工的食品的需求越来越大。我的研究项目，与国王大学学院的本科生，直接解决这个问题。我们正在研究大自然如何控制细菌种群，并调整这些策略，以开发新的食品腐败和致病菌的生物控制剂。我们的研究主要集中在以下问题：如何利用天然产生的有毒肽（微生物）杀死致病菌，以及如何利用噬菌体或其蛋白质选择性地消除食品腐败菌。我们的第一个项目涉及研究一种名为Microcin N（MccN）的小蛋白质的结构和作用方式。MccN是E.大肠杆菌作为一种自卫手段，并杀死致病性大肠杆菌菌株。大肠杆菌和沙门氏菌。具体来说，我们正在研究这种化合物的三维结构，并探索它如何靶向和杀死其他细菌，以便更好地了解其作为生物防腐剂的潜在用途。我们的第二个研究项目集中在表征杀死各种肉杆菌菌株的噬菌体。虽然这些细菌不是致病性的，但它们与肉制品的腐败有关。通过表征这些细菌及其溶素蛋白，我们将了解它们作为生物控制剂的作用，以延长包装肉类和鱼类产品的保质期。

The ability to control bacterial contamination in food is of extreme significance from both a health and economic perspective. An E. coli O157:H7 outbreak at XL Foods (Brooks, Alberta) in the fall of 2012 resulted in the largest ever food recall in Canada. While no deaths were linked to that outbreak, the economic repercussions were staggering. In 2011, a similar E. coli outbreak in Europe was responsible for thousands of infections and nearly 50 deaths. While food safety is clearly a major global concern, the addition of chemical additives to food is also under scrutiny. There is an increasing desire within the public sector for foods that are more natural and minimally processed. My research program, with undergraduate students at The King's University College, directly addresses this issue. We are studying how nature controls bacterial populations and adapting these strategies to develop new agents for the biocontrol of food spoilage and pathogenic bacteria. Our research is focused on the following questions: how can naturally produced toxic peptides (microcins) be used to kill pathogenic bacteria, and how can bacteriophages or their proteins be used to selectively eliminate food spoilage bacteria. Our first project involves studying the structure and mode of action of a small protein called microcin N (MccN). MccN is produced naturally by E. coli as a means of self-defence and kills pathogenic strains of E. coli and Salmonella. Specifically, we are studying the three dimensional structure of this compound and exploring how it targets and kills other bacteria, in order to better understand its potential use as a biopreservative. Our second research project is focused on characterizing bacteriophages that kill various strains of Carnobacteria. While these bacteria are not pathogenic, they are associated with spoilage of meat products. By characterizing these phages and their lysin proteins, we will understand their role as biocontrol agents to extend the shelf life of packaged meat and fish products.