Sep. 1, 2006 - Aug. 31, 2009Award Number
Center for Produce SafetyAmount Awarded
Brian Wilkinson, Ph.D.
Illinois State University
The foodborne bacterial pathogen Listeria monocytogenes is the cause of listeriosis, a serious disease with a fatality rate of about 25%. The organism has a unique ability to grow in food at refrigeration temperatures, and this leads to expensive product recalls. This research addresses the mechanisms operating that enable Listeria to grow at low temperatures with particular reference to ready-to-eat meats. We are searching for novel mechanisms for control of growth at refrigeration temperatures. In its cytoplasmic membrane lipids L. monocytogenes produces high amounts of the branched-chain fatty acid anteiso C15:0. We believe that this is a major determinant of the ability of Listeria to grow at low temperatures through imparting an essential fluidity to the membrane. We will investigate the mechanisms operating to ensure the high levels of anteiso C15:0 through cloning, over expressing, purifying and determining the substrate preferences of key enzymes in the biosynthesis of branched-chain fatty acids. We will investigate whether the fatty acid composition of Listeria can be modified to one that does not support growth at low temperatures by feeding selected fatty acid precursors to the bacterium. Finally, we will use DNA microarray technology to study gene expression of the organism in an actual food matrix. It is our expectation that these studies will lead to improved methods for control of the growth of L. monocytogenes