Summary of Awards to Date

Phenotypic and molecular studies to facilitate improved control of L. monocytogenes and Salmonella transmission.

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Jul. 1, 2009 - Jun. 30, 2012

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Martin Wiedmann, Ph.D
Cornell University


A study published in 1999 estimated that 76 million cases of gastrointestinal food-borne illnesses occur in the US on an annual basis, resulting in at least 325,000 hospitalizations and 5,000 deaths. While subsequent data indicated that the incidence of human listeriosis and selected other food-borne disease decreased since these initial estimates, 2008 data indicate no further declines in food-borne illness frequencies. Thus, food-borne illnesses and their medical sequelae continue to have a significant negative impact on human health and well being. Food recalls due the presence of food-borne pathogens are not uncommon and have significant negative economic consequences for the food industry. To track and control sources of food-borne pathogens, agricultural and food industries have a critical need for access to advanced molecular and genetics based tools, including future employees trained in the use of these tools. The overall goal of this project is to assure access to these advanced tools, by the food and meat industries to aid in their efforts to control food-borne pathogens. Thus, one of the goals of this project is the further development and expansion of a WWW-based publicly available DNA sub-type database for microorganisms causing food-borne illnesses. Further goals of this project include applications of this database to (i) help detect food-borne disease outbreaks and outbreak sources, (ii) develop improved "DNA fingerprinting" methods for food-borne pathogens, (iii) develop a better under-standing of the transmission, and evolution of food-borne pathogens, (iv) to define specific bacterial sub-types that differ in their ability to cause food-borne disease, and (v) provide scientific information that can be used to enhance risk assessments for food-borne illnesses. L. monocytogenes causes about 2,500 human food-borne listeriosis cases and 500 deaths annually in the US and has been commonly found in many different environments. This food-borne pathogen thus represents a considerable concern, not only due to its ability to cause severe human disease, but also because contamination of Ready-To-Eat food products with this organism is not uncommon. Recalls due to the presence of L. monocytogenes are thus not uncommon and both, human listeriosis cases and costly recalls, place a significant financial and emotional toll in the US population and national economy. Salmonella causes an estimated 1.4 million cases of food-borne disease annually in the US, including approximately 550 deaths. L. monocytogenes and Salmonella combined thus cause approx. 1,050 food-borne deaths annually in the US, out of an estimated total 1,800 deaths due to known food-borne pathogens. Significant efforts in this project are thus focused on the development of an improved understanding of farm-to-table food-borne transmission and ecology of L. monocytogenes and Salmonella, including the development and application of better tools to control and minimize contamination with these bacteria throughout the food system.