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

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.