Picture of Charles W. Kaspar

Charles W. Kaspar

Professor and Chair, Department of Bacteriology, UW-Madison

Address: 1550 Linden Drive
Phone: (608) 263-6936
Office: 3554 Microbial Sciences Building
Email: cwkaspar@wisc.edu

Department Webpage



  • BS 1980, Biology, University of Nebraska–Omaha
  • MS 1983, Microbiology, Iowa State University
  • PhD 1986, Microbiology, Iowa State University
  • Postdoc, 1986–88, University of Maryland

Research Interests

E. coli O157:H7; Stress-response systems; Pre-harvest food safety; Molecular and physiological mechanisms of acid tolerance

Research Focus

Reduced water activity (aw) is an effective antimicrobial barrier used to preserve food, but outbreaks involving low-aw foods such as dry spices and peanut butter, demonstrate that some salmonellae are able to survive these conditions. Therefore, a thorough understanding of how this pathogen adapts and responds to low-water conditions is essential to devise effective manufacturing processes and environmental control practices. Stress tolerance in foodborne pathogens involves a number of interconnected networks that control growth and protection systems. Our studies have demonstrated that osmotic and desiccation tolerance varies among Salmonella serovars as well as cells within a clonal population. Comparisons between tolerant and sensitive cells by RNA-seq found differences in the level of Crl transcript, as well as other transcripts, while other assays determined there were differences in phosphate levels. Previous studies in our laboratory have demonstrated that the RpoS regulon is necessary for osmotic and desiccation tolerance. Crl is an accessary regulatory element that interacts and partitions RpoS (i.e., ss) to degradation or RNA polymerase. My laboratory continues to investigate the role of Crl and phosphate in the underlying circuits of Salmonella and their contribution to population heterogeneity and stress tolerance, particularly osmotic and desiccation stress tolerance.

Recent Publications

ARYZTACampbell Soup CompanyConAgra FoodsFonterraGeneral MillsGreat Lakes CheeseHormel Foods (Jennie-O Turkey Store)Johnsonville Foods KelloggKerry Ingredients and FlavoursKraft Foods (Oscar Mayer Foods)Leprino FoodsPepsiCoSchreiber Foods