Food Microbiology Commons^™

Evaluating The Impact Of Region, Vintage, And Carbon Dioxide-Based Winemaking Techniques On Wine Quality Of Mediterranean Varietals, Coleman R. Imrisek

Master's Theses

Changing Vitis vinifera ripening patterns as a result of increasing climate variability has provided challenges against the production of wines with a balanced sensory profile, with adequate acidity, color, aroma, and texture. This thesis aimed to evaluate the ripening patterns and wine profiles of potentially climate-adaptive Mediterranean varietals in two different California Central Coast climates. Additionally, different carbon-dioxide based winemaking techniques were also assessed. Viognier and Grenache Noir grapes were sourced from the warmer, diurnal Paso Robles AVA and the cooler, marine Santa Maria AVA during the 2024 and 2025 growing seasons, with Syrah and Grenache Blanc grapes being only …

Examining The Ligands, Location, And Function Of Toll-Like Receptor 10, Kiefer Keanu Tam

Master's Theses

Toll-like receptors are a class of innate immune pattern recognition receptors that detect pathogen-associated molecular patterns and regulate downstream inflammatory responses. Toll-like receptor 10 remains the only human TLR whose ligand specificity, cellular localization, and immunological function are not fully defined. Emerging evidence suggests that TLR10 may play an anti-inflammatory role and can heterodimerize with TLR2 to modulate immune signaling. Previous studies from our laboratory demonstrated that stimulation with heat-killed Mycobacterium tuberculosis promotes TLR2-TLR10 heterodimerization and trafficking to the cell surface. In this study, we expanded our ligand panel to include additional gram-positive bacteria, particularly anti-inflammatory probiotic species, to further …

Effects Of Fermented Soybean Products On The Human Gut Microbiome, Microbial Metabolism, And Host Physiology, Shannon Moncier

Biology Dissertations

Fermented soybean products (FSPs) contain soybean-derived substrates, fermentation-associated microorganisms, and bioactive compounds that may interact with the human gut microbiome and host physiology. However, despite the growing interest in FSPs, longitudinal human studies specifically evaluating traditional Korean-FSPs (K-FSPs), particularly among United States-based populations, remain limited. The objective of this work was to evaluate the effects of three K-FSPs, including Cheonggukjang, Gochujang, and Doenjang, on host physiological responses, gut microbial community structure, predicted microbial functional potential, and fecal butyrate responses in healthy adults. Three independent dietary intervention cohorts were conducted using FSP formulations produced either by traditional artisan methods (Product A) …

Surrogate-Based Approaches For Evaluating Post-Harvest Food Safety Interventions In Fresh Produce, Md Shafiul Islam Rion

Graduate Theses, Dissertations, and Problem Reports (ETD)

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 …

State Case Count As An Indicator Of Successful Multistate Outbreak Investigation, Lorisa M. Pennell

Capstone Experience: Master of Public Health

Background/Objectives: Shiga-Toxin producing Escherichia coli (STEC) is a contaminant found in multiple food types and causes multistate outbreaks due to the industrialization of food production. In this report I examine the differences in outbreaks categorized by the regulating agency responsible in outbreak prevention and compare outbreak case counts when organized by positive outbreak investigation and response outcomes.

Methods: STEC Multistate outbreak data was obtained from the Center for Disease Control’s National Outbreak Reporting System (NORS) for outbreaks occurring from 2006-2023. Outbreaks were organized into those regulated by either the US Food and Drug Administration (FDA) or the US Department of …

Impacts Of Utilizing Reverse Osmosis Concentrate On Mashing, Fermentation, And Water Use In Bourbon Whiskey Production, Ryan C. Sarhan

Theses and Dissertations--Biosystems and Agricultural Engineering

This thesis addresses the feasibility of reusing reverse osmosis concentrate (ROC) in the bourbon whiskey fermentation processes. Initial work compared laboratory-scale mashing and fermentation methods, demonstrating that simultaneous saccharification and fermentation reliably reflects industrial-scale processes, with lower complexity and process time. Building upon this, laboratory and distillery-scale experiments demonstrated that reusing ROC in the mashing and fermentation steps does not negatively impact ethanol yields. ROC produced by systems with a water softener was found to significantly increase mash rheology, suggesting a need for potential process adjustments. Softened ROC also altered the production of flavor-influencing volatile congeners. Under worst case conditions, …

Inactivation Kinetics Of Escherichia Coli And Listeria Monocytogenes In Edible Insects, Precious Aduloju

Graduate Theses, Dissertations, and Problem Reports (ETD)

Edible insects are emerging as sustainable and nutritious alternatives to conventional protein sources. However, concerns about food safety, particularly the presence of pathogenic bacteria such as Escherichia coli and Listeria monocytogenes, remain a barrier to consumer acceptance and industrial use. This study evaluated the effectiveness of thermal processing in inactivating E. coli, L. monocytogenes, and their non-pathogenic surrogates (E. coli JM109 and Listeria innocua) in both fresh and dehydrated forms of Tenebrio molitor (mealworm) and Acheta domesticus (cricket). It also evaluated the influence of insect species, moisture content, and temperature on microbial inactivation. A microbial challenge …

Comparative Evaluation Of Fungal Strains For The Bioprocessing Of Soybean Hulls Using Cheese Whey As Fermentation Medium, Ruchita Bhattarai

Electronic Theses and Dissertations

Globally, soybean is the most widely cultivated oilseed crops, and serve as the primary source of cooking oil, contributing to around 50% of global oilseed production. During the industrial processing of soybean oil, a significant amount of soybean hull (SH) is produced, which makes up about 8% of the grain yield, resulting in approximately 18–20 million tons of hulls, one of the largest by-products in the soybean industry. The hulls have limited commercial value and are primarily used as fiber additives in dairy cattle feed, but a large portion is still discarded as agricultural waste. Similarly, cheese whey (CW), a …

Interactions Between High-Pressure Processing And Natural Antimicrobials In Ground White-Meat Chicken: An Analysis Of Microbial, Textural Charactheristics And Physicochemical Changes, Amalia M. Diaz Alejandro

All Theses

High Pressure processing is an innovative technique for preserving a wide variety of foods, including meat, and this method is increasingly used to satisfy consumer demand for quality food products. High-pressure treatment can impact, negatively or positively, various aspects of meat quality, including color, texture, protein denaturation, and microbial stability, particularly when food products are processed at ambient or low temperatures. By minimizing thermal exposure, appropriate high-pressure ranges help to prevent quality and nutrition degradation, reduce microbial contamination, and enhance tenderness.

The first objective of this research was to examine the influence of high-pressure processing and addition of natural antimicrobials …

Lmpact Of Salmonella Enterica Effector Proteins On Plant Physiology And Immunity, Sara Qader

Honors Theses

Salmonella enterica serovar Typhimurium are primarily recognized as pathogens associated with foodborne illnesses in humans. Salmonella also can colonize plant tissue effectively. The pathogen relies on type III secretion systems (T3SS) to infect mammals and plants successfully and counteract the immune response. Understanding the molecular mechanisms underlying Salmonella’s interactions with plants is essential for developing effective strategies to reduce its impact on human health and agriculture. Effector proteins, known for their role in modulating host-pathogen interactions, have been implicated in the virulence and pathogenicity of Salmonella. However, their specific functions and contributions to Salmonella’s interactions with plants remain largely unknown. …

Optimization Of Pre-Enrichment And Screening Methods For The Detection Of Salmonella Enterica In Meat Analog Products, Kylie Sacapano

Food Science (MS) Theses

With the growing demand and variety of meat analogs on the commercial market, there is a need to revisit the methodology for the detection of foodborne pathogens in these products. The current Food and Drug Administration (FDA) regulatory methods for Salmonella enterica detection in meat analogs follow the Bacteriological Analytical Manual (BAM) and are time-consuming and costly, requiring pre-enrichment using lactose broth (LB) with a surfactant (e.g., Triton X-100). Therefore, this study aimed to optimize pre-enrichment and screening methods for the detection of Salmonella in meat analogs by comparing the current FDA reference methods to updated techniques. To achieve this, …

Determination Of Factors Influencing Microbial Food Safety Risks Of Additive Manufacturing And 3d Printing Of Food, Allyson Nichole Hamilton

Graduate Theses and Dissertations

The burgeoning field of 3D food printing introduces opportunities for customizing the physicochemical properties of food, offering tailored solutions in color, shape, and texture. Despite its potential, the implications of this technology on food safety, particularly the efficacy of manufacturer-recommended cleaning protocols for stainless steel food ink capsules, the transferability of pathogens from a contaminated food ink capsule into the food ink based on macronutrient composition of the food, and the impact of storage conditions on pathogen viability, have not been thoroughly investigated. This dissertation provides a comprehensive analysis of these aspects, focusing on the control of foodborne pathogens and …

Exploring The Potential Of Electromagnetic-Driven Energy Technologies In Preventing Microbial And Aflatoxin Contamination Of Grains, Abass A. Oduola

Graduate Theses and Dissertations

Electromagnetic-driven energy such as infrared (IR) technology holds great potential in deactivating Aspergillus flavus spores and prevents aflatoxin B1 (AFB1) contamination. Aflatoxins, highly toxic secondary metabolites primarily produced by Aspergillus species within the Flavi section (A. flavus, A. parasiticus, and A. nomius), pose substantial health risks to both humans and animals due to their significant toxicity and carcinogenic properties. Detecting and quantifying the presence and proliferation of these harmful fungi on food materials can be achieved by measuring the concentration of ergosterol. Ergosterol is a sterol compound produced in the cell membranes of fungi during their growth, providing …

Cultivating Excellence: A Literature Review On Harnessing The Power Of The Gut Microbiome For Athletic Performance, Maya Katharine Dean

Honors Projects

The interplay between our gut microbiome and health is immense. This literature review analyzes the current research assessing the interplay between gut microbiome and athletic performance. Knowing how to improve gut microbial diversity via nutrition and supplementation can take athletic performance to the next level; namely improvements in immune, mental, and physical health.

Anti-Listeria Of H2o2-Peroxyacetic Acid Anti-Listeria Efficacy Of A Hydrogen Peroxide-Peroxyacetic Acid Mixer In Bacterial Buffered Solution And On Bell Peppers, Peighton Denae Foster

Graduate Theses, Dissertations, and Problem Reports (ETD)

This study aims to 1) evaluate the efficacy of H₂O₂-peroxyacetic acid (PAA) mixer to inactivate Listeria monocytogenes in 0.1% buffered-peptone-water; 2) evaluate the reduction and mitigation of cross-contamination on peppers. For the study-1, aliquots of 1.0-ml mixer solutions (0.25, 0.50 and 0.84%) were added to the first 3-well of 8-strip-deep-well microplates. Then, the 0.1 ml of 10-fold dilution the Nalidixic-acid-resistant (NaL) L. monocytogenes was added and mixed immediately with a multichannel pipette. After exposure for 0, 5, 15, 30, and up to 120-s, 1 ml of 2×D/E neutralized solution was added to terminate the reaction followed …

Disinfection Of Foodborne Bacteria Using The Contamination Sanitization Inspection And Disinfection (Csi-D) Device, Jennifer Mccoy Sanders

Food Science (MS) Theses

Foodborne pathogens, including Escherichia coli, Salmonella enterica, and Listeria monocytogenes, are major causes of gastrointestinal disease globally. The Contamination Sanitization Inspection and Disinfection (CSI-D) device is a new handheld fluorescence-based imaging system designed to disinfect food contact surfaces contaminated with microorganisms using ultraviolet-C (UVC) illumination. This study aimed to determine the optimal parameters for the disinfection of foodborne bacteria using the CSI-D device. The following bacterial strains were tested: generic E. coli; enterohemorrhagic E. coli (EHEC) O157:H7; enterotoxigenic E. coli (ETEC) O78:H11; S. enterica serotypes Enteritidis, Newport, Typhimurium, and Javiana; and L. monocytogenes serotypes 1/2a, 1/2b, and 4b …

Developing Disinfection Strategies For Controlling Human Norovirus, Sars-Cov-2, And Clostridioides Difficile Endospores In Long-Term Care Facilities, Jinge Huang

All Dissertations

Long-term care facilities (LTCFs) provide an environment favorable for the transmission of three critical human pathogens: human norovirus (HuNoV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and Clostridioides difficile. Given residents in LTCFs are susceptible to infections due to their advanced ages and compromised immune systems, effective environmental surface disinfection plays a crucial role in controlling the spread of human pathogens within these settings and, therefore, mitigates the risk of infections caused by these pathogens. This dissertation aimed to assess the efficacy of various types of disinfectants against two HuNoV surrogates [feline calicivirus (FCV) and Tulane virus (TuV)], two …

Thawing And Storage Effects On Quality Of Plant-Based Sausage Patties, Dakota Cook

All Theses

Maintaining sausage analogue quality during a thawing process and storage is important for increasing consumer satisfaction. Following new trends and prevalence of plant-based meats and a flexitarian diet, two experiments were conducted to test how thawing methods (experiment 1) and storage temperatures (experiment 2) affect meat analogue quality. For Experiment 1, Jimmy Dean Original Sausage Patties Made with Pork & Turkey, Morningstar Veggie Original Patties and Beyond Sausage Original Patties were purchased pre-frozen and subsequently thawed in one of three ways: 1. thawed at 4°C for 24 hours, 2. thawed at room temperature (22°C±2°C) for 4 hours and 3. thawed …

Effect Of Authentic Kefir And Nigella Sativa On Broilers Challenged By Coccidia And Clostridium Perfringens, Julian E. Nixon

All Dissertations

Black seed oil concentrations of 0%, 0.1%, 1% and 5% were added to milk inoculated with kefir grains and incubated at 25°C for 22 h. The pH and microbial count indicated 1% black seed oil caused low inhibition (P > 0.05) of fermentation, but 5% black seed oil caused significant inhibition of the kefir microorganisms (P < 0.05).

Cobb 500 male chicks (n = 256) were distributed in a randomized block design and received one of four treatments: CTRL1 (Non-medicated, no kefir, no Clostridium perfringens), CTRL2 (Non-medicated, no kefir, C. perfringens inoculated), CTRL3 (BMD medicated, no kefir, C. perfringens inoculated), KTRT (Non-medicated, …

Linking The Metabolic And Ecological Fate Of Caribbean Ciguatoxins And Related Neurotoxins In Reef Herbivores, Jessica K. Gwinn

Graduate Theses and Dissertations (2019 - present)

Ciguatera poisoning (CP) is one of the most prominent seafood-borne illnesses worldwide, affecting between 25,000–500,000 people annually. Ciguatera is caused by the ingestion of seafood contaminated with algal-derived ciguatoxins (CTX), the precursors of which are produced by benthic and toxigenic dinoflagellates in the genera Gambierdiscus and Fukuyoa. These compounds enter marine food webs through herbivory and are subsequently transferred to higher trophic levels, undergoing complex metabolic biotransformations, which produce structurally related CTX derivatives. Consumption of CTX induces a variety of severe neurological, gastrointestinal, and/or cardiovascular symptoms beginning within hours and lasting for weeks to months following exposure. Despite the impact …

Characteristics Of Yogurt And Culture Bacteria As Affected By Ingredients That Help Treat Leaky Gut, Ricardo Jose Santos Aleman

LSU Doctoral Dissertations

At least 100 million people have leaky gut syndrome. This syndrome is associated with multiple health problems such as diabetes, celiac disease, asthma, multiple sclerosis, and inflammatory bowel disease, costing more than $3 billion per year to treat. L-Glutamine, quercetin, slippery elm bark, marshmallow root, N-acetyl-d-glucosamine (NAG), licorice root, maitake mushrooms, and zinc orotate have been reported to help treat leaky gut.

The objectives were to explore the characteristics of yogurt and culture bacteria as affected by ingredients that help treat leaky gut. In yogurt, the pH, titratable acidity, syneresis, viscosity, color, Streptococcus thermophilus, Lactobacillus bulgaricus, yeast and mold and …

Evaluation Of Potential Surrogates For Listeria Monocytogenes In Fresh Citrus-Specific Validation Studies, Kimiko Grace Casuga

Master's Theses

The FSMA Produce Safety Rule (PSR) requires citrus packers to more closely assess, manage, and monitor food safety risks. Although there have been no foodborne illness outbreaks and only one recall in fresh citrus, the risk of pathogens coming in on the fruit and cross contamination during washing still exists. Packhouses have dynamic washing systems and in-plant validations may be the only way to demonstrate compliance with the PSR. In-plant validations use surrogates in place of pathogens, and none have been identified or validated for citrus. The aim of this research was to identify a surrogate for use in fresh …

Determining The Effects Of Maternal Adiposity On Preterm Neonatal Microbiome And Short Chain Fatty Acid Profiles, Dalton James, William A. Clark Phd, Kristy L. Thomas

Undergraduate Honors Theses

The gut microbiota and its metabolites have vast impacts on the human digestive system, immune system, and health outcomes. Short chain volatile fatty acids (SCVFAs) present in feces can be representative of the interactions of the microbiota present in the gut. Low microbiota diversity in the human gut is highly associated with obesity and adverse health outcomes. Furthermore, the maternal microbiome has a direct impact on neonatal microbiota through various pathways such as environment, skin flora, breast milk composition, and vaginal secretions. This study is aimed to further understand the associations between various factors (maternal adiposity, gestational time, length of …

Single-Laboratory Validation For The Detection Of Salmonella Enterica In Meat Analog Products, Amanda Tabb

Food Science (MS) Theses

Meat analogs are becoming increasingly popular for health, environmental, and ethical reasons. However, these products are at risk for contamination with Salmonella enterica. Therefore, it is important to ensure that detection methods for S. enterica in meat analog products are effective. Currently, the Bacteriological Analytical Manual (BAM) chapter on Salmonella detection calls for pre-enrichment of meat analogs using lactose broth (LB) with added surfactants, Tergitol Anionic 7 or Triton X-100. However, it remains to be determined whether surfactants are necessary for pre-enrichment of meat analogs. Following pre-enrichment, screening with VIDAS is typically performed. While VIDAS is an effective screening method, …

Inhibiting Survival Of Salmonella During Desiccation Through The Use Of Naturally Occurring Signals, Joseph Headrick

Electronic Theses and Dissertations

A rising problem in agriculture is the increase of antibiotic-resistant Salmonella cases associated with chicken eggs, which transmit infection to humans. To counter this, new approaches to combat Salmonella in chickens and desiccated on eggshells are vital in the prevention of human foodborne illness. Disrupting signaling pathways with naturally occurring compounds provides a potential novel avenue for prevention of Salmonella infections, as this would disrupt sensing of these environments and inhibit subsequent optimal gene expression. Starting with signals identified in previous studies, salicylic acid was found to inhibit Salmonella desiccation survival on both eggshells and plastic. To expand upon this, …

Filth Flies As A Vector For Some Pathogenic Bacteria Transfer, Ahmet Buyukyavuz

All Dissertations

Two separate sets of experiments were conducted to determine the transfer of bacteria by flies. An Escherichia coli ampicillin-resistant strain with a fluorescent gene was used during the experiments. The first set of experiments were divided into two trials to measure the transfer of E. coli by fruit flies to apple slices and bologna during short term exposure. Short time exposure (1, 5 and 15 min) of flies to inoculated apple slices were tested in the first trial to determine the transfer of E. coli to flies. No difference (P>0.05) in the number of bacteria transferred to flies were …

Effect Of Type Of Mulch And Biological Soil Amendments Of Animal Origin (Bsaao) On Microbial Food Safety Risk On Cucumbers And Carrots Irrigated With Contaminated Or Chlorinated Water, Juan Fernando Moreira Calix

LSU Doctoral Dissertations

A comprehensive understanding of the effect biological soil amendments of animal origin and physical soil amendments have on produce contamination is important for developing strategies to mitigate this risk. Our studies investigated the persistence of generic E. coli, E. coli O157:H7 and Salmonella spp. in soil and produce surfaces with different BSAAO and mulch applications, as well as the effectiveness of chlorine treatments in reducing enteric bacteria in the field. Cucumbers harvested from plots with paper mulch had the highest levels of E. coli (3.76 Log CFU/cm²) while samples from maize mulch had the lowest levels (1.68 …

Analysis Of Experimental Antimicrobial Prevention Strategies Against Microbial Contamination Of Locally Harvested Poultry And Produce In West Virginia, Rebecca Breanne Stearns

Graduate Theses, Dissertations, and Problem Reports (ETD)

Fresh produce and poultry have been associated with several foodborne illness outbreaks. Strategies to mitigate these risks are a much-needed research priority; therefore, five experiments were conducted to analyze pathogen cross-contamination capabilities on produce and poultry. Microbial contamination prevention and reduction strategies were also studied.

In Chapter Two, three antimicrobial delivery methods in combination with increasing concentrations of hydrogen peroxide-peroxyacetic acid (H₂O₂-PAA) (0.05-0.25 ml/dL) were compared to evaluate their ability to reduce and prevent cross-contamination of Listeria monocytogenes (L. monocytogenes) and Listeria innocua (L. innocua) on inoculated apples. Apples have been …

Evaluation Of Welded And Polished Stainless-Steel Surfaces In Supporting Sporeformer Biofilms In Dairy Plants, Taghreed Almalki

Electronic Theses and Dissertations

No abstract provided.

Evaluate A Mixer Of Hydrogen Peroxide And Peroxyacetic Acid To Mitigate Microbial Cross-Contamination Of Salmonella Typhimurium And The Surrogate Enterococcus Faecium During Triple-Washing Of Butternut Squash, Jesica M. Temple

Graduate Theses, Dissertations, and Problem Reports (ETD)

Background: Recent foodborne illness outbreaks have been linked to fresh fruits and vegetables. For public safety, awareness of the risks of contamination from foodborne pathogens that can occur during post-harvest farming practices is essential to prevent foodborne outbreaks. Controlling the spread of foodborne pathogens on produce requires proper washing procedures, antimicrobials and doses. Given the speed and diversity of the produce being distributed, local incidents may become international emergencies. Methods: Studies were included if they assessed the efficacy of antimicrobials and various washing procedures and had to conclude the mitigation of cross-contamination of foodborne pathogens on produce grown in the …