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Laura Strawn

Associate Professor

Laura Strawn

Laura Strawn
401-A HABB1 (0924)
1230 Washington Street SW
Blacksburg, VA 24061


Food Microbiology, Food Safety


  • Ph.D., Food Science, Cornell University, 2014
  • M.S., Food Science, University of Florida, 2009
  • B.S., Food Science and Technology, University of California, Davis, 2007


2020-Present: Associate Professor, Department of Food Science & Technology, Virginia Tech, Blacksburg, VA

2014-2020: Assistant Professor - Department of Food Science & Technology, Eastern Shore AREC, Virginia Tech, Painter, VA 

2014: Postdoctoral Researcher - Cornell University, Ithaca, NY

Honors and Awards: 

  • Virginia Cooperative Extension poster “Applied Research” category, 1st Place, 2019
  • Virginia Cooperative Extension poster “Agent – Specialist Partnership” category, 3rd Place, 2017
  • FDA’s Leveraging/Collaboration Award, 2016
  • John and Shirley Gerken Professional Development Award, 2015
  • Career Development Grants for Postdoctoral Women, American Society for Microbiology, 2014


My position includes both a research (50%) and extension (50%) appointment. While this position does not have a formal teaching appointment, I have strived to guest lecture for both on- and off-campus classes, and provide leadership and participation in graduate training through advising students or serving on student committees. Additionally, starting in 2022, I will teach FST 5034: Good Agricultural and Manufacturing Practices; through the Virginia Tech Online Masters in Agricultural Life Sciences program (OMALS). My research and extension program focuses on reducing foodborne pathogen contamination throughout the produce supply chain. My overarching goal is to pair my two appointments, research and extension, to complement each other. To achieve this, I have applied research/extension objectives that include both field (e.g., sampling commercial packinghouses or harvesters) and laboratory (e.g., benchtop, growth chamber) experiments. Discovery from these projects is disseminated directly to stakeholders through numerous extension activities. My program empowers produce growers, packers, and other stakeholders in the supply chain to make risk-based decisions for their operations by providing them with science-based information and practical solutions to limit contamination events. 


FST 5034- Good Agricultural and Manufacturing Practices 

Research and Extension

  1. Development of best practices and mitigation strategies to enhance the microbial safety of fresh fruits and vegetables throughout the field to fork continuum. For example, investigating the survival, growth, and transfer of foodborne pathogens between contamination sources, produce and produce-contact surfaces. This research will generate a better understanding of pathogen behavior in the produce field to fork continuum and allow for the development of targeted interventions. 

  2. Use of subtyping to investigate the ecology and transmission of bacterial foodborne pathogens in produce pre- and post-harvest environments. For example, subtyping pathogenic isolates from produce packinghouses to map spatio-temporal contamination patterns to identify control strategies. 

  3. Development and dissemination of educational programs and resources to promote produce safety and assist in the Food Safety Modernization Act Produce Safety Rule compliance for growers, packers, distributors, and other stakeholders. 


*Strawn in bold

Girbal, M., L.K. Strawn, C.M. Murphy, C.A. Bardsley, D. Schaffner. 2020. ComBase models are valid for predicting fate of Listeria monocytogenes on ten whole intact raw fruits and vegetables. In Press J. Food Prot. 

Harrand, A.S., L.K. Strawn, P.M. Illas-Ortiz, M. Wiedmann, D.L. Weller. 2020. Listeria monocytogenes Prevalence Varies More Within Fields Than Between Fields Over Time on Conventionally Farmed New York Produce Fields. J. Food Prot. 83:1958-1966. 

Belias, A.M., L.K. Strawn, M. Wiedmann, D.L. Weller. 2020. Small Produce Farm Environments Can Harbor Diverse Listeria monocytogenes and Listeria spp. Populations. In Press J. Food Prot.

Gu, G., L.K. Strawn, A.R. Ottesen, P. Ramachandran, E.A. Reed, J. Zheng, R. Boyer, S.L. Rideout. 2020. Correlation of Salmonella spp. and Listeria monocytogenes in Irrigation Water to Environmental Factors, Fecal Indicators, and Bacterial Communities. In Press Frontiers in Microbiology 11, 3426. 

Dharmarha, V. R.R. Boyer, L.K. Strawn, T. Drape, J. Eifert, A. Vallotton, A. Pruden, and M.A. Ponder. 2020. An Assessment of Produce Growers Sanitizer Knowledge and Practices on the Correct Use of Sanitizers. Food Prot. Trends. 40:140-146. 

Pinton, S.P., C.A. Bardsley, C.M. Marik, R.R. Boyer, and L.K. Strawn. 2020. Fate of Listeria monocytogenes on Broccoli and Cauliflower Under Different Storage Temperatures. J. Food Prot. 83:858-864. 

Estrada, E.M., A.M. Hamilton, G.B. Sullivan, M. Wiedmann, F.J. Critzer, and L.K. Strawn. 2020. Prevalence, Persistence, and Diversity of Listeria monocytogenes and Listeria Species in Produce Packinghouses in Three U.S. States. J. Food Prot. 83:277-286.

Marik, C.M., J. Zuchel, D.W. Schaffner, and L.K. Strawn. 2020. Growth and Survival of Listeria monocytogenes on Intact Fruit and Vegetable Surfaces during Postharvest Handling: A Systematic Literature Review. J. Food Prot. 83:108-128.

Gu, G., L.K. Strawn, J. Zheng, E.A. Reed, and S.L. Rideout. 2019. Diversity and Dynamics of Salmonella enterica in Water Sources, Poultry Litters, and Field Soils Amended with Poultry Litter in a Major Agricultural Area of Virginia. Front. Microbiol. 17:2868.

Dharmarha, V., N. Pulido, R.R. Boyer, A. Pruden, L.K. Strawn, and M.A. Ponder. 2019. Effect of Post-Harvest Interventions on Surficial Carrot Bacterial Community Dynamics, Pathogen Survival, and Antibiotic Resistance. Intern. J. Food Microbiol. 291:25-34. 

Lee, J.J., J.D. Eifert, S. Jung, and L.K. Strawn. 2018. Cavitation Bubbles Remove and Inactivate Listeria and Salmonella on the Surface of Fresh Roma Tomatoes and Cantaloupes. Front. Sustain. Food Syst. 2:1-11. 

Bardsley, C.A., R.R. Boyer, S.L. Rideout, and L.K. Strawn. 2019. Survival of Listeria monocytogenes on the surface of basil, cilantro, dill, and parsley plants. Food Control. 95:90-94.

Fogler, K., G.K. Guron, L.L. Wind, I.M. Keenum, W. Cully Hession, K. Krometis, L.K. Strawn, A. Pruden, M.A. Ponder. 2019. Microbiota and Antibiotic Resistome of Lettuce Leaves and Radishes Grown in Soils Receiving Manure-Based Amendments Derived from Antibiotic-Treated Cows. Front. Sustain. Food Syst. 10:22.

Dharmarha, V., G.K. Guron, R.R. Boyer, B.A. Niemira., A. Pruden, L.K. Strawn, and M.A. Ponder. 2019. Gamma Irradiation Influences the Survival and Regrowth of Antibiotic-Resistant Bacteria and Antibiotic-Resistance Genes on Romaine Lettuce. Frontiers Microbiology. 10:710.  

Bardsley, C.A., L.N. Truitt, R.C. Pfuntner, M.D. Danyluk, S.L. Rideout, and L.K. Strawn. 2019. Growth and Survival of Listeria monocytogenes and Salmonella on whole and sliced cucumbers. J. Food Prot. 82:301-309. 

Truitt, L.N., K.M. Vazquez, R.C. Pfuntner, S.L. Rideout, A.H. Havelaar, and L.K. Strawn. 2018. Microbial Quality of Agricultural Water Used in Produce Preharvest Production on the Eastern Shore of Virginia. J. Food Prot. 81: 1661-1672. 

Gu, G., L.K. Strawn, D.O. Oryang, J. Zheng, E.A. Reed, A.R. Ottesen, R.L. Bell, Y. Chen, S. Duret, D.T. Ingram, M.S. Reiter, R.C. Pfuntner, E.W. Brown, and S.L. Rideout. 2018. Agricultural Practices Influence Salmonella Contamination and Survival in Pre-Harvest Tomato Production. Front. Microbiol. 10:2451.

Escamilla Sanchez, D., R. Rosso, L.K. Strawn, B. Zhang. 2017. Evaluation of important seed and sprout traits as potential selection criteria in breeding new varieties for sprout soybeans. Euphytica. Accepted, EUPH-D-16-00564R1.

Topalcentiz, Z., L.K. Strawn, and M.D. Danyluk.  2017.  Microbial quality of agricultural water in Central Florida.  PLoS One.  12(4): e0174889.

Wang, S., F.O. Mardones, A.D. Adell, D. Weller, J. Falardeau, L.K. Strawn, A.M. Switt. 2016. Food safety trends: from globalization of whole genome sequencing to application of new tools to prevent foodborne diseases. Trends Food Sci Tech. 57:188-198.   

Weller D., S. Swakoti, P. Bergholz, Y. Grohn, M. Wiedmann, L.K. Strawn. 2016. Validation of a Previously Developed Geospatial Model that Predicts Listeria monocytogenes Prevalence for New York State Produce Fields. Appl. Environ. Microbiol. 82:797-807.

Brar P., L.K. Strawn, M. Danyluk. 2016. Prevalence, Level, and Types of Salmonella Isolated from North American In-Shell Pecans over Four Harvest Years. J. Food Prot. 79:352-360. 

Bergholz P., L.K. Strawn, G. Ryan, S. Warchocki, M. Wiedmann. 2016. Spatiotemporal Analysis of Microbiological Contamination in New York State Produce Fields following Extensive Flooding from Hurricane Irene, August, 2011. J. Food Prot. 79:384-391.

Weller, D., M. Wiedmann, and L.K. Strawn. 2015. Spatial and Temporal Factors Associated with an Increased Prevalence of Listeria monocytogenes in Spinach Fields in New York State. Appl. Environ. Microbiol. 81:6059-6069.

Strawn, L.K., E. Brown, J. David, H. den Bakker, P. Vangay, F. Yiannas, M. Wiedmann. 2015. Big Data in Food Safety and Quality. Food Tech. 69:42-49. 

Weller, D., M. Wiedmann, L.K. Strawn. 2015. Irrigation is Significantly Associated with an Increased Prevalence of Listeria monocytogenes in Produce Production Environments in New York State. J. Food Prot. 78:1132-1141. 

Chapin, T.C., K.K. Nightingale, R.W. Worobo, M. Wiedmann, L.K. Strawn. 2014. Geographical and Meteorological Factors Associated with Isolation of Listeria species in New York State Produce Production and Natural Environments. J. Food Prot. 77:1919-1928. 

Strawn, L.K., M.D. Danyluk, R.W. Worobo, M. Wiedmann. 2014. Distributions of Salmonella Subtypes Differ Between Two US Produce Growing Regions. Appl. Environ. Microbiol. 80:3982-3991. 

H.C. den Bakker, S. Warchocki, E.M. Wright, A.F. Allred, C. Ahlstrom, C.S. Manuel, M. J. Stasiewicz, A. Burrell, S. Roof, L.K. Strawn, E. Fortes, K.K. Nightingale, D. Kephart, M. Wiedmann. 2014. Five New Species of Listeria (L. floridensis sp. nov., L. aquatic sp. nov., L. cornellensis sp. nov., L. riparia sp. nov., and L. grandensis sp. nov.) from Agricultural and Natural Environments in the United States. Int. J. Syst. Evol. Microbiol. 64:1882-1889.

Strawn, L.K., Y.T. Grohn, S. Warchocki, R.W. Worobo, E. A., Bihn, M. Wiedmann. 2013. Risk Factors Associated with Salmonella and Listeria monocytogenes Contamination of Produce Fields. Appl. Environ. Microbiol. 79:7618-7627. 

Strawn, L.K., E.D. Fortes, E.A. Bihn, K.K. Nightingale, Y.T. Grohn, R.W. Worobo, M. Wiedmann, P.W. Bergholz. 2013. Landscape and meteorological factors affecting prevalence of three food-borne pathogens in fruit and vegetable farms. Appl. Environ. Microbiol. 79:588-600. 

Strawn, L.K., K.R. Schneider, and M.D. Danyluk. 2011. Microbiological Safety of Tropical Fruits. Crit. Rev. Food Sci Nutr. 51:132-145. 

Strawn, L.K. and M.D. Danyluk. 2010. Fate of Escherichia coli O157:H7 and Salmonella spp. on Fresh and Frozen Cut Pineapples. J. Food Prot. 73:418-424. 

Strawn, L.K. and M.D. Danyluk. 2010. Fate of Escherichia coli O157:H7 and Salmonella spp. on Fresh and Frozen Cut Mangoes and Papayas. Intern. J. Food Microbiol. 138:78-84.