- Increase our understanding of an important foodborne psychrotrophic [cold-growing] pathogen and how it resists the food preservation strategy of chilling;
- Provide the scientific basis for improved control strategies for L. monocytogenes.
Listeria monocytogenes is a foodbome pathogenic bacterium that causes listeriosis, a disease encompassing meningitis, abortions, and still births, which has a fatality rate of about 25%. This bacterium has the unusual ability to grow at refrigeration temperatures. The highest risk foods for listeriosis are ready to eat and stored at refrigeration temperatures for long periods, and are contaminated with high levels of the bacterium. Food producers incur considerable costs due to product recalls of contaminated foods. A recent high profile multi-state outbreak involving several deaths was traced to coldcuts from a meat producing plant in Michigan. We are studying the membrane fluidity of L. monocytogenes, and the genes and proteins involved in growth of the organism at low temperatures. Using the technique of electron paramagneticresonance we will examine the hypothesis that even at low temperatures there is a fluid region in the membrane consisting of fatty acids surrounding membrane proteins. Novel genes involved in low temperature growth will be identified through differences in gene expression [messenger RNA production] at low temperatures. Proteins produced in elevated amounts inresponse to low temperatures will be identified using 2-dimensional electrophoresis. The proposed research aims to: 1] increase our understanding of an important foodborne psychrotrophic [cold-growing] pathogen and how it resists the food preservation strategy of chilling; and 2] provide the scientific basis for improved control strategies for L. monocytogenes.