Author ORCID Identifier
Semester
Spring
Date of Graduation
2026
Document Type
Dissertation
Degree Type
PhD
College
Davis College of Agriculture, Natural Resources and Design
Department
Animal and Nutritional Sciences
Committee Chair
Cangliang Shen
Committee Member
Jacek Jaczynski
Committee Member
Kristen Matak
Committee Member
Timothy Boltz
Abstract
Pathogenic bacteria are still a threat to human beings worldwide as their presence is often unknown even if they are already present in fresh produces. This in turn resulted in several outbreaks and recalls across the United States. This dissertation investigated the survival of pathogenic bacteria and their potential non-pathogenic surrogates after antimicrobial interventions in different modes of applications on the surface of cantaloupes, butternut squash, and fresh cilantro. In the first study, peroxyacetic acid (PAA) was applied in three separate doses on nalidixic acid resistant Salmonella Typhimurium, Listeria monocytogenes, Enterococcus faecium, and Listeria innocua inoculated cantaloupe surfaces using triple-wash (water + water + antimicrobial) technique. The findings concluded that triple wash with 96 ppm PAA was the most effective treatment against both pathogenic and surrogate bacteria. In addition, E. faecium showed higher or similar resistance against antimicrobial washing compared to S. Typhimurium and L. monocytogenes, which ensured its potential as a good surrogate in similar antimicrobial intervention studies on cantaloupes. The second study evaluated the survival of S. Typhimurium, L. monocytogenes, L. innocua, and E. faecium on either untreated or 70% ethanol and UV light pre-treated butternut squash during the aerobic storage at 22.5°C and 40.6% relative humidity for 30 days. Bacteria population reduction from the initial inoculated population fitted Linear, Linear with Tail, and Biphasic models. Moreover, Salmonella and Listeria cell numbers decreased by 3.8-4.1 log10 CFU/cm2 during storage, while E. faecium reduced by < 1.0 log10 CFU/cm2, which supported the suitability of E. faecium as a proper surrogate of Salmonella and L. monocytogenes on squash during storage. And the final study investigated the impact of spraying techniques and antimicrobial efficacy of two essential oils (EO; eugenol and trans-cinnamaldehyde) in reducing S. Typhimurium, L. monocytogenes, and E. faecium from a microgreen surfaces (i.e. fresh cilantro). Both essential oils were sprayed at three different concentrations with two distinct sprayers for 60 s on bacteria inoculated fresh cilantro separately. The least-square means for overall bacteria cell reduction from fresh cilantro was significantly (P < 0.05) lower for E. faecium than Salmonella; however, L. monocytogenes exhibited the highest resistance against all the treatment combinations. Results also revealed that 3% eugenol application with garden sprayer rendered the highest bacteria population reduction and E. faecium qualified as a good surrogate of Salmonella for similar EO antimicrobial interventions in future. Overall, this dissertation outlined suitable application methods and doses of different antimicrobials to reduce the pathogenic bacteria load from several fresh produces while validating E. faecium as a potential surrogate for similar studies in future.
Recommended Citation
Rion, Md Shafiul Islam, "Surrogate-based Approaches for Evaluating Post-harvest Food Safety Interventions in Fresh Produce" (2026). Graduate Theses, Dissertations, and Problem Reports. 13181.
https://researchrepository.wvu.edu/etd/13181