Rolf Joerger

Photo of Rolf Joerger
Department of Animal and Food Sciences

Rolf Joerger

Associate Professor of Food Science

Office location:
531 S. College Avenue
018 Townsend Hall
Newark, DE 19716

Resources and links


  • Post-doctoral fellowships, USDA-ARS, DuPont, 1987-1996
  • Ph.D. in Microbiology, North Carolina State University, 1987
  • Diplom, Universität Hohenheim, Stuttgart, Germany, 1983

Current courses

  • ANSF 102 – Food For Thought 
  • ANSF 390 – Honors Colloquium: Food, glorious food – challenges for the 21st century
  • ANSF 449/649 – Food Biotechnology
  • ANSF 411 – Food Science Capstone


  • Food-borne pathogens
  • Antimicrobials
  • Salmonella physiology and genetics

Professional activities

  • Member of Institute of Food Technologists
  • Member American Society of Microbiologists
  • Associate Editor, Bioresource Technology


R. D. Joerger, Casey A. Sartori, and Kalmia E. Kniel. 2009. Comparison of genetic and physiological properties of Salmonella enterica isolates from chickens reveals one major difference between serovar Kentucky and other serovars: Response to acid. Foodborne Pathogens and Disease.6(4):503‐512

Haiqiang Chen, Hudaa Neetoo, Mu Ye, and Rolf D. Joerger. 2009. Differences in pressure tolerance of Listeria monocytogenes strains are not correlated with other stress tolerances and are not based on differences in CtsR. Food Microbiology. 26(4):404‐408.

Rolf D. Joerger, Casey A. Sartori, and Kalmia E. Kniel. 2008. Salmonella enterica Kentucky isolates from chickens exhibit low tolerance to hydrochloric acid-induced pH 2.5. Submitted for publication.

Rolf D. Joerger, Subramaniam Sabesan, Donna Visioli, Dave Urian, Melissa C.Joerger.2008. Antimicrobial Activity of Chitosan Attached to Ethylene Copolymer Films. Accepted for publication in Packaging Technology and Science.

Hudaa Neetoo, Mu Ye, Haiqiang Chen, Rolf D. Joerger, Doris T. Hicks, Dallas G. Hoover. 2008. Use of nisin-coated plastic films to control Listeria monocytogenes on vacuum-packaged cold-smoked salmon. International Journal of Food Microbiology. 122:8–15

Higgins, J., Hohn, C., Hornor, S., Frana, M., Denver, M., and Joerger, R. 2007. Genotyping of Escherichia coli from environmental and animal samples. J. Microbiol. Methods. 70:227-235.  Doi:10.1016/jmimet.2007.04.009

Joerger, R. D. 2007. Antimicrobial films for food applications: an analysis of quantitative results. Packaging Technology and Science. 20:231-273. DOI: 10.1002/pts.774

Guan D, Joerger R.D., Kniel K.E., Calci K.R., Hicks D.T., Pivarnik L.F. and Hoover D.G. 2007. Effect of high hydrostatic pressure on four genotypes of F-specific RNA bacteriophages (f2, GA, Q? and SP) J. Applied Microbiology. 102 (1):51-56.

Joerger, R. D, H. Chen, and K. E. Kniel. 2006. Characterization of a spontaneous, pressure-tolerant Listeria monocytogenes Scott A ctsR deletion mutant. Foodborne Pathogens & Disease. 3:196-202.

Joerger, R.D. and T. Ross. 2005. Genotypic diversity of Escherichia coli isolated from cecal content and mucosa of one- to six-week-old broilers. Poult. Sci. 84:1902-1907.

Chen, H. Q., R. D. Joerger, D. H. Kingsley, and D. G. Hoover. 2004. Pressure inactivation kinetics of phage lambda cI 857. J. Food Prot., 67:505-511.

Zhu, X. Y, and R. D. Joerger. 2003. Composition of Microbiota in Content and Mucus from Cecae of Broiler Chickens as Measured by Group-specific, 16S rRNA-targeted Oligonucleotide Probe Hybridization. Poult. Science, 82:1242-1249.

Joerger, R. D. 2003. Alternatives to Antibiotics: Bacteriocins, Antimicrobial Peptides and Bacteriophages. Poult. Science, 82:640-647.

Strapp, C. M., A. E. H. Sheares, and R. D. Joerger. 2003. Survey of Retail Alfalfa Sprouts and Mushrooms for the Presence of Escherichia coli O157:H7, Salmonella and Listeria Using BAX, and Evaluation of this PCR-Based System with Experimentally Contaminated Samples. J. Food Prot., 66:182-187.

Zhu, X. Y. T. Zhong, Y. Pandya, and R. D. Joerger. 2002. 16S rRNA-Based Analysis of Microbiota from the Cecum of Broiler Chickens. Appl. Environ. Microbiol., 68:124-137.

Shearer, E. H., C.M. Strapp, and R. D. Joerger. 2001. Evaluation of a PCR-based Detection System, BAX, for Detection of Salmonella enterica serovar Enteritidis, Escherichia coli O157:H7,Listeria sp. and Listeria monocytogenes on Fresh Fruits and Vegetables. J. Food Protect., 64:788-795.