Martin Wiedmann is a Professor in the Department of Food Science. He received a Veterinary Degree (DVM equivalent) and Dr. med. vet. (Ph.D. equivalent) in Veterinary Medicine both from the University of Munich, Germany and a Ph.D. in Food Science from Cornell University. He joined the Cornell faculty in 1999 and is a member of the Graduate Fields of Food Science, Microbiology, and Comparative Biomedical Sciences. He serves as co-coordinator of the Cornell Food and Water Safety Program, and he participates in the Infection and Pathobiology Program, the Cornell Center for Comparative and Population Genomics (3CPG),and in the Cornell Genomics Initiative. He teaches Food Science 607 "Advanced Food Microbiology", Food Science 351 "Milk Quality", Food Science 406 "Dairy and Food Fermentations" and VTMED 741 Microbial Safety of Animal-Based Foods . In addition, he serves as the director of the Cornell Institute of Food Science Summer Scholar Program. Martin is also the director of the Cornell Laboratory of Molecular Typing. Martin has served on the Editorial Board of the American Journal of Veterinary research (1999-2001) and currently serves on the Editorial Board of the Journal of Food Protection and on the Editorial Board of Applied and Environmental Microbiology.

Research in Martin's laboratory focuses on the molecular pathogenesis, ecology, epidemiology evolution, and transmission of bacterial and foodborne diseases with a particular focus on two foodborne pathogens, Listeria monocytogenes and Salmonella. Our overall goal is to generate an improved understanding of the transmission of foodborne bacterial pathogens from farm animals and from foods to humans. A better understanding of the transmission pathways of foodborne pathogens is necessary to design better strategies to prevent and control human disease. Both basic and applied research work in our lab is thus targeted towards developing the scientific knowledge necessary to improve our ability to prevent foodborne diseases.

L. monocytogenes is a foodborne pathogen capable of causing serious invasive human and animal disease, including abortion, septicemia, meningitis and meningoencephalitis. Among humans, immunocompromised persons and neonates are particularly at risk of listerial infections. An estimated 2,500 cases of clinical listeriosis occur annually in the U.S., resulting in a total of about 500 deaths. Due to its severe consequences, listeriosis is a major public health concern. L. monocytogenes is also commonly found in nature and in food processing environments and has the ability to survive for extended time periods outside animal hosts. Thus, control of this organism represents a serious challenge for the food industry.

Salmonella infections are typically contracted through the consumption of contaminated food, or water or through contact with an infected host.  Salmonella is one of the leading causes of foodborne illness in the United States and the European Union with estimated incidences of 15.1 cases per 100,000 persons in the US and 42.2 cases per 100,000 persons in the EU.  Specifically, in the US an estimated 1.4 million human foodborne salmonellosis cases, including approximately 550 deaths, occur annually. While most Salmonella infections do not require treatment, and result in temporary gastroenteritis, in more invasive, life-threatening cases, the use of antimicrobial drugs is required.  The emergence and spread of antimicrobial-resistant Salmonella strains, particularly those that are resistant to multiple antimicrobial drugs (i.e., multi-drug resistant [MDR] Salmonella) is, thus, a major public health concern.

Specific research projects in our laboratory are targeted (i) at understanding differences among distinct L. monocytogenes strains in abilities to cause human and animal disease; (ii) at understanding the role of stress response systems (and specifically alternative sigma factors) in the ability of L. monocytogenes to survive in foods and to cause disease; (iii) to develop and apply improved molecular typing methods for L. monocytogenes to help to detect and track human and animal listeriosis cases and to track sources of L. monocytogenes in food plants and on farms; (iv) to better understand the evolution of virulence in L. monocytogenes. Research projects utilize cutting edge molecular biology and pathogenesis approaches (including tissue culture and animal studies), (v) to better understand the ecology and transmission of Salmonella with a particular focus on multi-drug resistant Salmonella. Our research studies are also supported by a collection of more than 5000 human, animal and food L. monocytogenes isolates and more than 1,000 Salmonella isolates. Characterization of these isolates will allow us to gain further insight into the molecular evolution of these important human and animal pathogens.

Research in our laboratory is conducted in collaboration with other universities, private industry and federal and state agencies. For example, through collaboration on molecular fingerprinting of L. monocytogenes with the New York State Department of Health and other health departments, our research group recently contributed to the detection of a large multistate outbreak of human listeriosis cases which was ultimately linked to consumption of contaminated hot dogs and deli meats. We are also collaborating with computer scientists at Cornell to develop bacterial subtype databases to allow rapid exchange of DNA subtyping information for foodborne pathogens.