Our research at Penn State is focused on precision food safety.

We are integrating next generation sequencing, bioinformatics, epidemiological, molecular and traditional microbiological methods to investigate genetic and environmental factors driving the

  1. Expression of virulence factors;
  2. Evolution of antimicrobial resistance and
  3. Transmission of foodborne pathogens.

We aim to translate the information and knowledge generated through our research projects into practical solutions to increase food safety and security and thereby enhance the sustainability of modern agricultural and food systems.

Precision Food Safety


The mission of our lab is to create environment and resources conducive to

  1. Innovative, productive, responsible and reproducible undergraduate and graduate research with positive societal impact;
  2. Promotion of STEM among women and diversity groups and
  3. Training of a new generation of food scientists equipped with microbiological and bioinformatics skills and broad understanding of societal challenges related to food safety.


Our lab's values are aligned with the Penn State core values.

Integrity: We act with integrity and honesty in accordance with the highest academic, professional, and ethical standards.

Respect: We respect and honor the dignity of each person, embrace civil discourse, and foster a diverse and inclusive community.

Responsibility: We act responsibly, and we are accountable for our decisions, actions, and their consequences.

Discovery: We seek and create new knowledge and understanding, and foster creativity and innovation, for the benefit of our communities, society, and the environment.

Excellence: We strive for excellence in all our endeavors as individuals, an institution, and a leader in higher education.

Community: We work together for the betterment of our University, the communities we serve, and the world.


Kovac lab co-authors are indicated in bold type; corresponding author is indicated with *.


Liao, J., Hohl Orsi, R., Carroll, L. M., Kovac, J., Ou, H., Zhang, H., Wiedmann, M*. 2019. Serotype-specific evolutionary patterns of antimicrobial-resistant Salmonella enterica. BMC Evolutionary Biology, doi.org/10.1186/s12862-019-1457-5.

Kovac, J. Precision food safety: a paradigm shift in detection and control of foodborne pathogens. 2019. mSystems, doi.org/10.1128/mSystems.00164-19.

Harrand, A. S., Kovac, J., Carroll, L. M., Guariglia-Oropeza, V., Kent, D. J., Wiedmann, M. 2019. Assembly and characterization of a pathogen strain collection for produce safety applications: Pre-growth conditions have a larger effect on peroxyacetic acid tolerance than strain diversity. Frontiers in Microbiology, doi.org/10.3389/fmicb.2019.01223.

Weller, L. D., Kovac, J., Kent, D. J., Roof, S., Tokman, J. I., Mudrak, E., Wiedmann, M.*. A conceptual framework for developing recommendations for no-harvest buffers around in-field feces. 2019. Journal of Food Protection, doi.org/10.4315/0362-028X.JFP-18-414.

Reichler, S. J., Martin, N. H., Evanowski, R. L., Kovac, J., Wiedmann, M., Orsi, R. H. 2019. A century of gray: a genomic locus found in 2 distinct Pseudomonas spp. is associated with historical and contemporary color defects in dairy products worldwide. Journal of Dairy Science, doi.org/10.3168/jds.2018-16192.

Bell, T. H., Hockett, K., Alcala-Briseno, R. I., Barberchek, M., Beattie, G. A., Bruns, M. A., Carlson, J., Chung, T., Collins, A., Emmett, B., Esker, P., Garrett, K., Glenna, L., Gugino, B. K., del Mar Jimenez Gasco, M., Kinkel, L., Kovac, J., Kowalski, K., Kuldau, G., Leveau, J., Mischalska-Smith, M., Myrick, J., Peter, K., Vivanco Salazar, Shade, A., Stopinsek, N., Tan, X., Wickings, K., Tergeau, E. 2019. Manipulating wild and tamed phytobiomes: Challenges and opportunities. Phytobiomes, doi:10.1094/PBIOMES-01-10-0006-W.

Beno, S. B., Orsi, R. H., Cheng, R. A., Kent, D. J., Kovac, J., Duncan, D. R., Martin, N. H., Wiedmann, M. 2019. Genes associated with psychrotolerant Bacillus cereus group isolates. Frontiers in Microbiology, doi:10.3389/fmicb.2019.00662.

Carroll, L.M., Wiedmann, M., Mukherjee, M., Nicholas, D.C., Mingle, L.A., Dumas, N.B., Cole J.A., Kovac, J.* 2019. Characterization of emetic and diarrheal Bacillus cereus strains from 2016 foodborne outbreak using whole-genome sequencing: addressing the microbiological, epidemiological, and bioinformatic challenges. Frontiers in Microbiology, doi:10.3389/fmicb.2019.00144.

Nwanosike, H., Chung, T., Xiaoli, L., Condello, M., Dudley, E. G., Kovac, J.* 2019. Whole-genome sequences of Escherichia coli isolates from cocoa beans imported from Bolivia. Microbiology Resource Announcements, doi:10.1128/MRA.01516-18.


Miller, R. A., Jian, J., Beno, S. M., Wiedmann, M., Kovac, J.*. 2018. Intraclade variability in toxin production and cytotoxicity of Bacillus cereus group type strains and dairy-associated isolates. Applied and Environmental Microbiology, doi: 10.1128/AEM.02479-17.

Smole Mozina, S., Klancnik, A., Kovac, J., Jersek, B., Bucar, F*. 2018. Antimicrobial natural products against Campylobacter. In Merillon, J. M., Riviere, C. (Eds). Natural Antimicrobial Agents. Sustainable Development and Biodiversity, vol. 19., Springer, Cham, doi:10.1007/978-3-319-67045-4_1.


Goodman, L. B., Lawton, M. R., Franklin-Guild, R. J., Anderson, R. R., Schaan, L., Thachil, A. J., Wiedmann, M., Miller, C. B., Alcaine, S. D.*, Kovac, J.*. 2017. Lactococcus petauri sp. nov. is a new species isolated from an abscess of a sugar glider. International Journal of Systematic and Evolutionary Microbiology, doi:10.1099/ijsem.0.002303.

Carroll, L. M., Kovac, J.*, Miller, R. A., Wiedmann, M. 2017. Rapid, high-throughput identification of anthrax-causing and emetic Bacillus cereus group genome assemblies using BTyper, a computational tool for virulence-based classification of Bacillus cereusgroup isolates using nucleotide sequencing data. Applied and Environmental Microbiology, doi:10.1128/AEM.01096-17

Weller, D., Kovac, J., Roof, S., Kent, D, Tokman, J., Kowalcyk, B., Oryang, D., Ivanek, R., Aceituno, A., Sroka, C., Wiedmann, M*. 2017. Survival of Escherichia coli on lettuce under field conditions encountered in the Northeastern United States. Journal of Food Protection, 80(7), 1214-1221.

Weller, D. L., Kovac, J., Kent, D. J., Roof, S., Tokman, J. I., Mudrak, E., Kowalcyk, B., Oryang, D., Aceituno, A., Wiedmann, M*. 2017. Escherichia coli transfer from simulated wildlife feces to lettuce during foliar irrigation: A field study in the Northeastern United States. Food Microbiology, 68: 24-33.

Kovac, J., den Bakker, H., Carroll, L. M., Wiedmann, M*. 2017. Precision food safety: a systems approach to food safety facilitated by genomics tools. TrAC Trends in Analytical Chemistry. In Press, https://doi.org/10.1016/j.trac.2017.06.001

Kovac, J., Stessl., B., Cadez, N., Gruntar, I., Cimerman, M., Stingl, K., Lusicky, M., Ocepek, M., Wagner, M., Smole Mozina, S*. 2017. Population structure and attribution of human clinical Campylobacter jejuni isolates from central Europe to livestock and environmental sources. Zoonoses and Public Health, doi: 10.1111/zph.12366

Liao, J., Wiedmann, M., Kovac, J*. 2017. Genetic stability and evolution of sigB allele used for Listeria sensu stricto subtyping and phylogenetic inference. Applied and Environmental Microbiology, doi:10.1128/AEM.00306-17.

Kovac, J., Cummings, K. J., Rodriguez-Rivera, L. D., Carroll, L. M., Thachil, A., Wiedmann, M.*. 2017. Temporal genomic phylogeny reconstruction indicates a geospatial transmission path of Salmonella Cerro in the United States and a clade-specific loss of hydrogen sulfide production. Frontiers in Microbiology, doi: 10.3389/fmicb.2017.00737.


Miller, A. R., Beno, S. M., Kent, D. J., Carroll, L. M., Martin, N. H., Boor, K. J., Kovac, J*. 2016. Bacillus wiedmannii sp. nov. is a new psychrotolerant and cytotoxic Bacilluscereus group species isolated from dairy foods and environments in the USA. International Journal of Systematic and Evolutionary Microbiology, Accepted for publication on Aug 12, doi: 10.1099/ijsem.0.001421.

Kovac, J., Miller, R. A., Carroll, L. M., Kent, D. J., Jian, J., Beno, S. M., Wiedmann, M*. 2016. Production of hemolysin BL by Bacillus cereus group isolates of dairy origin is associated with whole-genome phylogenetic clade. BMC Genomics, 17:581, doi: 10.1186/s12864-016-2883-z.

Kovac, J., Cadez, N., Stessl, B., Stingl, K., Gruntar, I., Ocepek, M., Trkov, M., Wagner, M. and Mozina, S.S.*. 2015. High genetic similarity of ciprofloxacin-resistant Campylobacter jejuni in central Europe. Frontiers in Microbiology, 6:1169, doi: 10.3389/fmicb.2015.01169.


Kovac, J., Simunovic, K., Wu, Z., Klancnik, A., Bucar, F., Zhang, Q.*, Mozina, S.S.*.2015. Antibiotic resistance modulation and modes of action of (-)-α-pinene in Campylobacter jejuni. PLoS One, 10(4):e0122871, doi: 10.1371/journal.pone.0122871.

Nagy, B.*, Szmolka, A., Mozina, S.S., Kovac, J., Strauss, A., Schlager, S., Beutlich, J., Appel, B., Lusicky, M., Aprikian, P. and Pászti, J.. 2015. Virulence and antimicrobial resistance determinants of verotoxigenic Escherichia coli (VTEC) and of multidrug-resistant E. coli from foods of animal origin illegally imported to the EU by flight passengers. International Journal of Food Microbiology, 209:52-9, doi: 10.1016/j.ijfoodmicro.2015.06.026.

Before 2015

Videnska, P., Rahman, M.M., Faldynova, M., Babak, V., Matulova, M.E., Prukner-Radovcic, E., Krizek, I., Smole-Mozina, S., Kovac, J., Szmolka, A. and Nagy, B.*.2014. Characterization of egg laying hen and broiler fecal microbiota in poultry farms in Croatia, Czech Republic, Hungary and Slovenia. PLoS One, 9(10):e110076, doi: 10.1371/journal.pone.0110076.

Kovac, J., Gavaric, N., Bucar, F. and Smole Mozina, S.*, 2014. Antimicrobial and Resistance Modulatory Activity of Alpinia katsumadai Seed Phenolic Extract, Essential Oil and Post-Distillation Extract. Food Technology and Biotechnology, 52(2), 248-254.

Janez, N., Kokosin, A., Zaletel, E., Vranac, T., Kovac, J., Vuckovic, D., Mocina, S.S., Serbec, V., Zhang, Q., Accetto, T. and Podgornik, A.*. 2014. Identification and characterisation of new Campylobacter group III phages of animal origin. FEMS Microbiology Letters, 359(1), 64-71.

Kovac, J., Cadez, N., Lusicky, M., Nielsen, E.M., Ocepek, M., Raspor, P. and Mozina, S.S.*. 2014. The evidence for clonal spreading of quinolone resistance with a particular clonal complex of Campylobacter jejuni. Epidemiology and Infection, 142(12), 2595-2603.

Klancnik, A., Gröblacher, B., Kovac, J., Bucar, F. and Mozina, S.S.*. 2012. Anti-Campylobacter and resistance-modifying activity of Alpinia katsumadai seed extracts. Journal of Applied Microbiology, 113(5),1249-1262


FD SC 409 - Laboratory in Food Microbiology (Fall semester)

FDSC 497 - Foodborne Pathogen Genomic Epidemiology (Spring semester)

FDSC/INTAG 460 - Food Production in Italy (study abroad; Spring break)