Strategies to Enhance Food Safety: Characterization of Microcins and Bacteriophages

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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.