Food Microbiology Commons^™

Evaluating Variety- And Market-Class-Specific Effects Of Dietary Pulses On Human Health, Jiayu Tang

Department of Food Science and Technology: Dissertations, Theses, and Student Research

While pulses are globally recognized for their high levels of dietary fibers, protein, and polyphenols, research often focuses on characterizing the physiological effects of a single variety. This approach overlooks the substantial genetic and compositional diversity that exists across pulse varieties and individual market classes, which can differ extensively in nutrient content and structure. These compositional differences have the potential to produce distinct physiological and microbial responses in humans, yet variety- and market-class-specific effects remain poorly characterized.

This thesis uses two complementary research methodologies to investigate the health-relevant effects of different pulse varieties and market classes, providing foundational knowledge to …

Advancing Targeted Food Allergen Detection: Extraction Optimization And Sample Preparation Method Comparison Using Lc-Ms/Ms, Zhenhao Wang

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Accurate quantification of food allergens in processed foods by liquid chromatography-tandem mass spectrometry (LC-MS/MS) requires effective protein extraction and sample cleanup. However, no single sample preparation workflow has shown consistent performance across diverse food matrices. This study evaluated extraction buffer formulations and post-extraction cleanup strategies for quantification of milk, soy, and peanut allergens in multiple processed food matrices.

Six extraction buffers with varying combinations of SDS, urea, and thiourea alongside a common Tris-HCl/DTT/PVPP base were evaluated across five food matrices. No significant differences in extraction efficiency were observed among buffer formulations for nonfat dry milk (NFDM), non-roasted soy flour, peanut …

Detection And Quantification Of Allergen Cross-Contact In Shared Frying Oil Using Targeted Mass Spectrometry, Francisca Asigri

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Cow’s milk and egg allergies are prevalent IgE-mediated food allergies that pose significant public health concerns worldwide. Although strict avoidance remains the primary management strategy, unintended exposure can still occur through allergen cross-contact, particularly in commercial and industrial food operations that utilize shared frying oils. The objective of this study was to identify and quantify allergen transfer in shared frying oil and assess the robustness of existing targeted mass spectrometry methods (LC-MS/MS) for detecting milk and egg proteins in heated oil matrices.

Heated oil spikes were developed by incorporating non-fat dry milk (NFDM) and whole egg powder (WEP) into oil …

Defining The Causal Contribution Of The Gut Microbiota To Cardiomyopathy Pathogenesis As A Basis For Developing Microbiome-Targeted Therapies, Xu Shi

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Heart failure (HF) is a leading cause of morbidity and mortality worldwide, placing substantial clinical and economic burdens on society. Although advances in therapy have improved patient outcomes, the biological mechanisms that drive HF onset and progression remain incompletely understood. Increasing evidence suggests that the gut microbiota, the trillions of microorganisms residing in the gastrointestinal tract, plays a key role in some forms of heart disease, especially cardiovascular disease. Moreover, gut microbial dysbiosis has been associated with systemic inflammation, metabolic imbalance, and immune dysregulation, all of which contribute to the pathophysiology of HF. Cardiomyopathy, a primary disorder of the heart …

Comparison Of Pcr-Based Methods For The Detection Of Canned Tuna Species, Chloe P. Castanon, Denise Hernandez, Akshay N. Khetrapal, Rosalee S. Hellberg

Food Science Faculty Articles and Research

Canned tuna is susceptible to mislabeling due to its high consumer demand, complex global supply chains, and range of prices. DNA barcoding of a short fragment of the mitochondrial control region (CR), termed the CR mini-barcode, has been established as an effective method for tuna species identification. However, the high level of DNA degradation in canned tuna products reduces the effectiveness of this method. Therefore, this study aimed to compare CR mini-barcoding to targeted (i.e., real-time or multiplex) PCR-based methods to determine the most effective approach for canned tuna species identification. DNA was extracted in duplicate from 24 canned tuna …

Assessment Of Microbial Quality And Safety, Including Aflatoxin B1, In Buckwheat Flour And Groats, La Fontaine Bahatsi

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Buckwheat (Fagopyrum esculentum), a gluten-free pseudocereal, has gained popularity in global food markets for its nutritional value and functional properties. However, despite its health-promoting potential, buckwheat is vulnerable to microbial contamination and mycotoxin accumulation during cultivation, processing, and storage. These factors present significant food safety concerns that remain understudied, particularly in North America.

This study investigated the microbiological quality and mycotoxin contamination of buckwheat flour and groats collected from different suppliers via online sourcing. Samples were collected in two consecutive years (2024-2025). Microbiological quality, including aerobic plate counts (APC), Enterobacteriaceae, coliforms, E. coli, yeasts, and molds, was evaluated …

Cazyme Gene Cluster Diversity In Human Gut Microbiome, Yi Xing

Department of Food Science and Technology: Dissertations, Theses, and Student Research

In gut microbiome research, carbohydrate-active enzyme gene clusters (CGCs) have emerged as key functional units for understanding microbial glycan degradation. Unlike taxonomic or broad pathway annotations, CGCs offer gene-cluster-level resolution and capture substrate-specific microbial functions. However, their diversity and distribution in relation to host metabolic phenotypes, such as obesity, remain poorly characterized. This study tests the hypothesis that the composition and abundance of fiber-targeting CGCs vary between obese and healthy human gut microbiomes, reflecting distinct microbial carbohydrate utilization strategies. To examine this, we constructed a high-quality reference CGC dataset comprising 94,019 clusters from the Unified Human Gastrointestinal Genome and profiled …

One Health Interventions And Challenges Under Rural African Smallholder Farmer Settings: A Scoping Review, Evanson R. Omuse, Honest Machekano, Bonoukpoè M. Sokame, Daniel M. Mutyambai, Thomas Dubois, Sevgan Subramanian, Frank Chidawanyika

All Peer-Reviewed Publications

The global human population is rapidly increasing, escalating interactions of people, animals and the environment. This has led to more convoluted health challenges, for which African smallholder farmers bear the brunt. The One Health (OH) approach recognises the interconnectedness of these health challenges and thus follows a transdisciplinary approach involving diverse stakeholders to address them. Although there have recently been global concerted efforts and studies on OH, an information gap exists in Africa, particularly regarding smallholder farmers and their needs. Additionally, evaluation frameworks and outcome metrics for OH initiatives are still unclear. Thus, this study was conducted to critically map …

Identification Of Antigens For Food Allergy And Food Allergen Detection, Ellenor Sell

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Antibody-based allergen testing is an essential part of allergen management in the food industry. These methods directly detect one or more molecules of the allergenic foodstuff (target’ molecule(s)) and the presence of the allergenic foodstuff is inferred. The identity of these target molecules is crucial to the performance of the method and the interpretation of results. The goal of this study was to develop protein/antibody capture methodology for the identification of antibody binding partners using mass spectrometry.

This study is broken down into three separate projects: the characterization of the antigen-antibody complexes present in sandwich ELISAs, LFDs, and human sera. …

Inactivation Of E. Faecium Nrrl B-2354 In Whole Black Pepper By Fluidization With Hydrogen Peroxide Vapor, Daniela Segura

Department of Food Science and Technology: Master of Science with Project Option

This study evaluated Enterococcus faecium NRRL B-2354 as a surrogate for Salmonella inactivation in black peppercorns treated with hydrogen peroxide (HP) vapor via fluidization. The selected parameter for dwell temperature was 60ºC for 60 minutes. The reduction of both Salmonella and E. faecium, along with changes in water activity, color, and residual hydrogen peroxide, were measured before, immediately after treatment and at 24 and 48 hours post-treatment. Results showed that E. faecium exhibited a significantly greater reduction (4.63 ± 0.55 log CFU/g) compared to Salmonella (2.94 ± 0.16 log CFU/g) (p < 0.05), making E. faecium unsuitable as …

Aflatoxin Prevalence And Association With Maize Grain Physical And Nutritional Qualities In The Informal Markets In Meru County, Kenya, C. Cherotich, M. W. Okoth, Abong’ Go, S. W. Kariuki, E. R. Omuse

All Peer-Reviewed Publications

In Kenya, aflatoxin contamination in maize remains a persistent issue, with potential negative impacts on both public health and economic growth. Aflatoxins are toxic secondary metabolites produced by certain mold species, primarily Aspergillus flavus. The extent of Aspergillus fungal invasion in maize grains and the resulting increase in aflatoxin levels is heavily influenced by pre-and post-harvest practices. Before harvest, factors such as insect damage and exposure to warm, humid conditions increase the crop's susceptibility to Aspergillus infection and subsequent aflatoxin formation. Post-harvest, additional risks arise when kernels are damaged by pests like rats or when they are stored in unfavorable …

Processed Amaranth And Finger Millet Enriched With Cricket Flour Influence The Functionality, Microbial Quality, Shelf Life, And Consumer Preference Of The Porridge Products, Nelly Maiyo, Michael Okoth, George Abong, Brian O. Ochieng, Fathiya Khamis, Margaret Kababu, Chrysantus M. Tanga

All Peer-Reviewed Publications

Exploration of nutritious, cheap, and easy-to-prepare locally available complementary foods using different processing techniques is gaining traction globally. This study evaluated the impact of three processing techniques (roasting, germination, and fermentation) on finger millet and amaranth quality. The implications of blending processed products with 10% cricket flour on the functional properties, microbial safety, and shelf life of the porridge products were tested. Thereafter, consumer preference and acceptability of the cooked porridge products were assessed with randomly enrolled panelist of mothers (20–66 years), as primary caregivers. Our results showed that powder from germinated cereal products had higher swelling power, water absorption …

Using Bivalves As An Indicator For Fecal Bacteria, Kamala Chuss

Honors Scholar Theses

This project focuses on the integration of fecal bacteria from warm-blooded animals into bivalve tissue, and the utilization of bivalves as an indicator for fecal bacteria in waterways. Bivalves may give a more representative long-term average of fecal bacteria in water as compared to direct water testing. The primary objective is to create a standard operating procedure to use bacterial testing of bivalves as a proxy for bacteria concentration in the water. This method can be used in places where bivalves do not already exist by adding them to a body of water, or by collecting bivalves that already exist …

Development Of Fortified Blended Food Using Great Northern Bean, Aemiro Tadesse Zula

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Undernutrition is a global health challenge affecting people across all stages of life. While everyone is susceptible, certain groups face a significant burden. These include those living in poverty, young children, adolescents, older people, and lactating and pregnant women. Food insecurity is another primary global concern affecting billions of individuals worldwide and is closely associated with undernutrition. Implementing interventions to address these two significant global burdens is critical, and international organizations are playing a crucial role through food aid programs using Fortified Blended Foods such as corn-soy blend (CSB), corn-soy blend plus (CSB+), and corn-soy blend plus plus (CSB++). CSB+ …

Effects Of Heat Moisture Treatment On Dietary Fiber Utilization By The Gut Microbiota, Yichen Bai

Department of Food Science and Technology: Dissertations, Theses, and Student Research

The present study investigates the impact of heat moisture treatment (HMT) on the utilization of dietary fibers from red lentil hulls and wheat bran and its subsequent effect on gut microbiota and short-chain fatty acid production. HMT significantly decreased the water absorption index in red lentil hulls but increased it in wheat bran. For resistant starch (RS), HMT elevated its content in red lentil hulls but diminished it in wheat bran. In terms of dietary fiber content, HMT increased soluble dietary fiber in red lentil hulls. However, carbohydrate utilization and SCFA production by gut microbiota did not significantly change after …

Microbial Transfer And Cross-Contamination In Milling Facilities And Pathogen Survival In Milled Products And Baking Mixes, Aryany Leticia Peña-Gomez

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Wheat-based products, traditionally considered low-risk due to their low moisture content, have been involved in numerous foodborne outbreaks in recent decades. Salmonella and Shiga toxin-producing Escherichia coli (STEC) present in these products have caused significant numbers of hospitalizations and massive product recalls. The microbiological quality of flour is highly dependent on the incoming wheat, which is vulnerable to contamination from field to milling. Once pathogens are present in flour, they can survive for extended periods. Implementing strategies to mitigate the risk of pathogen contamination throughout the wheat processing chain is critical.

This study evaluated the distribution of E. coli …

Development And Validation Of Aronia Melanocarpa Berry Recipes For Home Canning: Integrating Thermal Lethality Studies, Microbiological Safety, And Antioxidant Analysis, Juan Diego Villegas Posada

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Aronia melanocarpa, also known as chokeberry, is gaining popularity for its high antioxidant content and health benefits, including reducing oxidative stress and inhibiting cancer gene expression. However, its characteristic bitterness and astringency limit its broader appeal. Chokeberry's low pH places it in the acid foods category, making it ideal for safe home canning. An acidic environment combined with heat treatment inhibits harmful bacteria like Clostridium botulinum. Home canning preserves food by sealing it in airtight containers and heating it to destroy spoilage microorganisms.

Developing safe and palatable recipes is essential for making chokeberries suitable for home canning. A …

The Effect Of Fat Content On The Inactivation And Recovery Of Listeria Spp. In Ready-To-Eat Foods After High Pressure Processing, Yhuliana Kattalina Niño Fuerte

Department of Food Science and Technology: Dissertations, Theses, and Student Research

High-pressure processing (HPP) is recognized by the United States Department of Agriculture Food Safety and Inspection Service (USDA FSIS) as a post-lethality treatment to control Listeria monocytogenes in ready-to-eat (RTE) meat and poultry products. A scoping review of 603 journal articles, which ultimately was narrowed down to 16 articles, revealed that the efficacy of HPP varies with fat content. The studies demonstrated that L. monocytogenes inactivation by HPP tends to be lower in RTE meats with greater than 5% fat content, compared to products with lower than 5% fat. The wide range of HPP parameters used in these studies …

Twenty-Three Years Of Pcr-Based Seafood Authentication Assay Development: What Have We Learned?, Maleeka Singh, Robert G. Young, Rosalee S. Hellberg, Robert H. Hanner, Maria G. Corradini, Jeffrey M. Farber

Food Science Faculty Articles and Research

Seafood is a prime target for fraudulent activities due to the complexity of its supply chain, high demand, and difficult discrimination among species once morphological characteristics are removed. Instances of seafood fraud are expected to increase due to growing demand. This manuscript reviews the application of DNA-based methods for commercial fish authentication and identification from 2000 to 2023. It explores (1) the most common types of commercial fish used in assay development, (2) the type of method used, (3) the gene region most often targeted, (4) provides a case study of currently published assays or primer-probe pairs used for DNA …

Utilization Of Probiotics To Compete With Clostridioides Difficile For Nutrient-Niches In A Variety Of In Vitro Contexts, April Elizabeth Johnson

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Clostridium difficile is a major threat to public health and primarily affects at risk groups such as elderly, immunocompromised individuals, and individuals on antibiotics. Many decades of research have been conducted to figure out ways to exclude or reduce C. difficile colonization and toxin production. Two major proposed mechanisms for colonization resistance are production of secondary bile salts and competition for nutrients.

In Chapter 2, we found that antibiotic treatment disrupted bile salt metabolism increasing the levels of the primary bile salt cholate and decreasing the levels of deoxycholate, a secondary bile salt. However, bile salts were not required …

Assessment Of Foam Decontamination In Tomato Washing Process, Basim M. Alohali

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The work of the dissertation investigated the efficacy of foam-based decontamination treatments to enhance microbial safety in Roma tomatoes, specifically targeting natural microflora and Salmonella contamination. Growing concerns over foodborne illnesses linked to fresh tomatoes and the limitations of conventional decontamination techniques, such as organic matter built-up and limited microbial reduction, are addressed. The primary objectives were to characterize the physiochemical properties of foams formed using various concentrations of Tween 20 (T20) and sodium dodecyl sulfate (SDS) with and without the addition of sodium hypochlorite (NaOCl) and peracetic acid (PAA), compare the efficacy of foam and traditional dump tank (DT) …

Protein Oxidation In Aging And Alzheimer’S Disease Brain, Rukhsana Sultana, D. Allan Butterfield

Markey Cancer Center Faculty Publications

Proteins are essential molecules that play crucial roles in maintaining cellular homeostasis and carrying out biological functions such as catalyzing biochemical reactions, structural proteins, immune response, etc. However, proteins also are highly susceptible to damage by reactive oxygen species (ROS) and reactive nitrogen species (RNS). In this review, we summarize the role of protein oxidation in normal aging and Alzheimer’s disease (AD). The major emphasis of this review article is on the carbonylation and nitration of proteins in AD and mild cognitive impairment (MCI). The oxidatively modified proteins showed a strong correlation with the reported changes in brain structure, carbohydrate …

Salmonella Detection In Food Using A Hek-Htlr5 Reported Cell-Based Sensor, Esma Eser, Victoria A. Felton, Rishi Drolia, Arun K. Bhunia

Biological Sciences Faculty Publications

The development of a rapid, sensitive, specific method for detecting foodborne pathogens is paramount for supplying safe food to enhance public health safety. Despite the significant improvement in pathogen detection methods, key issues are still associated with rapid methods, such as distinguishing living cells from dead, the pathogenic potential or health risk of the analyte at the time of consumption, the detection limit, and the sample-to-result. Mammalian cell-based assays analyze pathogens’ interaction with host cells and are responsive only to live pathogens or active toxins. In this study, a human embryonic kidney (HEK293) cell line expressing Toll-Like Receptor 5 (TLR-5) …

Development Of An Intact Mass Spectrometry Method For The Detection And Differentiation Of Major Bovine Milk Proteins, Emily F. Harley-Dowell

Department of Food Science and Technology: Dissertations, Theses, and Student Research

The authentication of products with claims regarding protein sources or compositions is a challenge for traditional analytical methods, which generally lack the required specificity whole protein analysis can provide. For example, the establishment of milk as “A2” is achieved through genetic testing of cows before milk production, with no methods to authenticate milk products themselves. Establishment of A2 milk is completed through genetic testing of the cows before milk production, but with no methods to authenticate the milk products themselves. Intact protein mass spectrometry (MS) has the potential to directly authenticate protein products, including specific proteoform claims. The development of …

An Amplification-Free Crispr-Sers Biosensor For Specific, Sensitive And Rapid Detection Of Salmonella Typhimurium In Poultry, Fei Jia, Bingyan Li, Yawen He, Yafang Shen, Juhong Chen, Xingmin Li, Yanbin Li

Biological and Agricultural Engineering Faculty Publications and Presentations

CRISPR (Clustered regularly interspaced short palindromic repeats) has been a cutting-edge biotechnology in both gene editing and biosensing due to its desirable features, such as high base resolution and set-and-forget operation. However, as a nucleic acid detection method, an DNA/RNA amplification procedure is still inevitable in CRISPR biosensors. In this study, a highly-ordered nanopore array SERS substrate, coated with silver nanoparticles, was fabricated and utilized as a platform for the specific detection of Salmonella Typhimurium (S. Typhimurium) without the time-consuming DNA amplification step. The smart sensing strategy was established by introducing an ssDNA labeled with a Raman active molecule …

Aqueous Ozone Efficacy For Inactivation Of Foodborne Pathogens On Vegetables Used In Raw Meat-Based Diets For Companion Animals, Sahaana Chandran, Christopher A. Baker, Allyson N. Hamilton, Gayatri R. Dhulappanavar, Sarah L. Jones, Kristen E. Gibson

Food Science Faculty Publications and Presentations

The present study evaluates the efficacy of a batch wash ozone sanitation system (BWOSS) and spray wash ozone sanitation system (SWOSS) against Listeria monocytogenes (two strains) and Salmonella enterica subsp. enterica (three serovars) inoculated on the surface of carrots, sweet potatoes, and butternut squash, commonly used in raw meat-based diets (RMBDs) marketed for companion animals such as dogs and cats. Produce either remained at room temperature for 2 h or were frozen at −20°C and then tempered overnight at 4°C to mimic the preprocessing steps of a raw pet food processing operation (‘freeze-temper’) prior to ozone treatment. Two ozone concentrations …

Kluyveromyces Marxianus Prepared As A Ready To Use Supplemental Food (Rusf), Zachary Christman

Applied Science Program: Theses

Ready to Use Supplemental Food (RUSF) is a nutrient dense paste or compressed bar used to supplement a person’s nutritional needs because of malnutrition or due to food shortages. The purpose of this article is to demonstrate some methods of how the dairy organism Kluyveromyces marxianus can be used to enrich the protein value of bread or ferment a substrate such as wheat bran into a more digestible form.

Persistence Of Salmonella Enterica Subsp. Enterica Ser. Javiana, Listeria Monocytogenes, And Listeria Innocua In Hydroponic Nutrient Solution, Gayatri R. Dhulappanavar, Kristen E. Gibson

Food Science Faculty Publications and Presentations

This study aimed to determine the persistence of Salmonella Javiana, Listeria monocytogenes, and Listeria innocua in nonsterile, hydroponic nutrient solution (NS) at 15, 25, 30, and 37°C over a 21-day period to mimic time from seedling to mature lettuce. Bacteria were inoculated in modified Hoagland's NS at 106 CFU/mL and maintained at 15, 25, 30, and 37°C. Samples were collected at various time points, and bacteria were quantified. A mixed model was used to determine the effect of bacteria type, time (day), and temperature on bacteria concentration (log CFU/mL). The least-squares means were calculated to compare the mean log …

Influence Of Overcooking On Food Digestibility And In Vitro Fermentation, Wensheng Ding

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Areas of char or overcooking commonly appear in foods people consume. It has been reported that overcooked food is harmful to human health. However, little research exists on the effect of overcooking on in vitro protein and starch digestibility and gut microbial fermentation. This study aimed to reveal the connection between overcooking and in vitro protein and starch digestibility and gut microbial fermentation. In vitro protein digestibility of an overcooked ground beef patty was almost half that of a standard cooked sample (27 ± 2% versus 48 ± 6%, respectively; p = 0.02). Whole wheat bread protein digestibility was also …

Nutritional Characteristics, Microbial Loads And Consumer Acceptability Of Cookies Enriched With Insect (Ruspolia Differens) Meal, Brian O. Ochieng, Joseph O. Anyango, Fathiya M. Khamis, Sunday Ekesi, James Peter Egonyu, Sevgan Subramanian, John M. Nduko, Dorothy Nakimbugwe, Xavier Cheseto, Chrysantus M. Tanga

All Peer-Reviewed Publications

Utilization of Ruspolia differens Serville as functional food ingredient is rapidly gaining popularity. This study evaluated the nutrient quality, microbial safety and consumers’ acceptability of cereal-based cookies fortified with various processed products of R. differens meals. Cookies fortified with blanched, boiled, and toasted R. differens meals had higher protein, fat and energy levels, respectively, than the control cookies. Enrichment of cookies with differentially processed R. differens meals had elevated levels of isoleucine and leucine. Omega-3 fatty acid, methyl (9Z,12Z,15Z)-octadecatrienoate, was detected only in cookies prepared from wheat-insect meals blends. Blanched and boiled R. differens meal significantly (p < 0.05) boosted iron (1.70-folds) and zinc (1.12–1.16-folds) contents of the cookies. The cookie products had reduced Enterobacteriaceae, S. aureus, yeast and mould with permissible exposure limits for human consumption. The overall acceptability of insect-enriched cookie product by male and female respondents ranged between 57 and 80%. The survey revealed that the flavour, colour, mouthfeels and texture of the cookie products were important motivation for consumers to accept grasshoppers as a food source. Further research on the flavour of cookie products enriched with grasshopper meal would be required to increase acceptability to market-driven consumer appealing food products.