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Dissertations, Theses, & Student Research in Food Science and Technology

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Inactivation Of Escherichia Coli O157:H7 And Shiga Toxin Producing E. Coli (Stec) Throughout Beef Summer Sausage Production And The Use Of High Pressure Processing As An Alternative Intervention To Thermal Processing, Eric L. Oliver Dec 2015

Inactivation Of Escherichia Coli O157:H7 And Shiga Toxin Producing E. Coli (Stec) Throughout Beef Summer Sausage Production And The Use Of High Pressure Processing As An Alternative Intervention To Thermal Processing, Eric L. Oliver

Dissertations, Theses, & Student Research in Food Science and Technology

Escherichia coli O157:H7 and six additional serogroups of Shiga Toxin-producing E. coli (STEC-7) have been implicated in foodborne illness outbreaks related to fermented sausage products and are considered adulterants by the USDA-FSIS. The objective of this study was to evaluate high pressure processing (HPP) as an alternative to thermal treatment to reduce STEC-7 meeting the USDA-FSIS performance standards (5.0-log reduction). A rifampicin-resistant, non-pathogenic E. coli (surrogate) cocktail, was used in manufacturing testing. Sausages were fermented at ~42.2°C, slowly increased to 54.4°C internal temperature, cold showered, and chilled for 6 hours. Sampling occurred post-fermentation (PF ...


Efficacy Of Galactooliosaccharide (Gos) And/Or Rhamnose-Based Synbiotics In Enhancing Ecological Performance Of Lactobacillus Reuteri In The Human Gut And Characterization Of Its Gos Metabolic System, Monchaya Rattanaprasert Dec 2015

Efficacy Of Galactooliosaccharide (Gos) And/Or Rhamnose-Based Synbiotics In Enhancing Ecological Performance Of Lactobacillus Reuteri In The Human Gut And Characterization Of Its Gos Metabolic System, Monchaya Rattanaprasert

Dissertations, Theses, & Student Research in Food Science and Technology

Probiotic L. reuteri has potential to produce antimicrobial compounds and secrete immunosuppressive factors. These metabolic attributes could benefit the human host by providing colonization resistance (competitive and metabolic exclusion) against enteropathogens and mitigating inflammation. As metabolically active cells are fundamental to such probiotic properties, synbiotic approaches that supply L. reuteri with a source(s) of carbon, energy, and/or external electron acceptor for cell growth in the gut environment could therefore prompt the probiotic to engage in beneficial activities. In this study, the efficacy of GOS and/or rhamnose-based synbiotic approaches in promoting colonization persistence and metabolic activity of L ...


Preference Mapping Of Whole Grain And High Fiber Products: Whole Wheat Bread And Extruded Rice And Bean Snack, Ashley J. Bernstein Dec 2015

Preference Mapping Of Whole Grain And High Fiber Products: Whole Wheat Bread And Extruded Rice And Bean Snack, Ashley J. Bernstein

Dissertations, Theses, & Student Research in Food Science and Technology

The rise of unhealthy lifestyles and diets among Americans is leading to an influx of health-conscious consumers on the search for more nutritious, health-promoting food options that match their taste preferences. The aim of this research is to determine consumer preferences and specific attributes of whole grain and high fiber products that drive acceptability through descriptive analysis and preference mapping on whole wheat breads and an extruded pinto bean and brown rice flour snack puff.

Commercial whole wheat breads, characterized by 26 appearance, aroma, flavor, and texture attributes, were separated into two distinct groups. The first group consisted of attributes ...


Phenolic Rich Extracts Obtained From Small Red Beans In Preventing Macrophage Mediated Chronic Inflammation, Nidhi Sharma Nov 2015

Phenolic Rich Extracts Obtained From Small Red Beans In Preventing Macrophage Mediated Chronic Inflammation, Nidhi Sharma

Dissertations, Theses, & Student Research in Food Science and Technology

Small red beans, commonly called Mexican beans, are a part of the legume family, the genus Phaseolus vulgaris, i.e., dry edible beans or the common bean. In addition to being a rich source of nutrients, small red beans also contain phenolic compounds, such as flavonoids, tannins, phenolic acids, and anthocyanins that have shown a plethora of health benefits against such conditions as obesity, diabetes, heart disease and cancer. In particular, the phenolic compounds common to the red beans have been reported to protect against chronic inflammation that if left unchecked can lead to various other chronic degenerative diseases. These ...


Simulation And Validation Of Radio Frequency Heating Of Shell Eggs, Soon Kiat Lau Jul 2015

Simulation And Validation Of Radio Frequency Heating Of Shell Eggs, Soon Kiat Lau

Dissertations, Theses, & Student Research in Food Science and Technology

Finite element models were developed with the purpose of finding an optimal radio frequency (RF) heating setup for pasteurizing shell eggs. Material properties of the yolk, albumen, and shell were measured and fitted into equations that were used as inputs for the model. When the egg was heated by itself, heating tend to be focused at the air cell to result in a “coagulation ring.” The focused heating near the air cell of the egg prevented satisfactory pasteurization of the egg, but deeper analysis of the simulation results offered a new perspective on how non-uniform RF heating could occur in ...


Influence Of Native And Processed Cereal Grain Fibers On Gut Health, Junyi Yang Jul 2015

Influence Of Native And Processed Cereal Grain Fibers On Gut Health, Junyi Yang

Dissertations, Theses, & Student Research in Food Science and Technology

Cereal fibers that can be metabolized by gut microbiota have been shown to promote the growth of beneficial bacteria in the gut. Increased consumption of cereal fibers may improve host / gut microbiota interactions in obesity and other metabolic diseases by normalizing gut dysbiosis. The present dissertation describes four research projects to assess the impact of cereal dietary fibers on gut microbiota and host metabolism. In the first study, we determined the treatment temperatures for production of soluble, non-digestible, feruloylated oligo- and polysaccharides (FOPS) from maize bran and wheat bran, and determined the fermentation properties of partially purified FOPS from maize ...


Characterization And Investigation Of Fungi Inhabiting The Gastrointestinal Tract Of Healthy And Diseased Humans, Mallory J. Suhr May 2015

Characterization And Investigation Of Fungi Inhabiting The Gastrointestinal Tract Of Healthy And Diseased Humans, Mallory J. Suhr

Dissertations, Theses, & Student Research in Food Science and Technology

Gastrointestinal microbiome studies have failed to include fungi in total community analyses. As a result, their diversity and function in the gut is poorly understood. Recent work has begun to uncover the role intestinal fungi play in diet, immune system development, interactions with other microorganisms in the gut, and pathogenesis of diseases. Advances in sequencing technologies allow for the ability to profile the fungal gut microbiome (“mycobiome”) in healthy and diseased states. This thesis explores the mycobiome in 1) healthy humans with a vegetarian diet and 2) pediatric small bowel transplant recipients that develop fungal bloodstream infections.

The gut mycobiome ...


Effects Of Blanching On Color, Texture And Sodium Chloride Content During Storage Time Of Frozen Vegetable Soybean Modeling For Commercial Scale, Pimsiree Suwan May 2015

Effects Of Blanching On Color, Texture And Sodium Chloride Content During Storage Time Of Frozen Vegetable Soybean Modeling For Commercial Scale, Pimsiree Suwan

Dissertations, Theses, & Student Research in Food Science and Technology

Vegetable soybeans [Glycine max (L.) Merrill] are a green stage of soybeans, which have become increasingly popular among health-conscious Americans as an alternative low-fat and heart-healthy food. Vegetable soybeans (VSB) are also an excellent source of protein and fiber. However, the vast majority of the VSB consumed are imported, as they are not extensively grown and processed in the United States. The situation results in short supply and limited processing information.

The purpose of this study was to investigate the effects of water blanching (at 86, 92, 98 °C for 1m30s, 2m, 2m30s) and steam blanching (at 86, 92, 98 ...


The Influence Of The Bovine Fecal Microbiota On The Shedding Of Shiga Toxin-Producing Escherichia Coli (Stec) By Beef Cattle, Nirosh D. Aluthge May 2015

The Influence Of The Bovine Fecal Microbiota On The Shedding Of Shiga Toxin-Producing Escherichia Coli (Stec) By Beef Cattle, Nirosh D. Aluthge

Dissertations, Theses, & Student Research in Food Science and Technology

During the past three decades, Shiga toxin-producing E.coli (STEC) have emerged as an important food safety concern. Although initially E. coli O157 was the main focus, recent outbreaks and resulting investigations have shown that certain non-O157 STEC are as much a threat to food safety as their O157 counterparts. To the beef industry, STEC have been of particular concern due to the frequent association of beef and beef products as vehicles of STEC infection. As a result, along with E. coli O157, six non-O157 STEC serogroups (known as the ‘big six’) are now regulated as adulterants in certain raw ...


Corn Characterization And Development Of A Convenient Laboratory Scale Alkaline Cooking Process, Shreya N. Sahasrabudhe May 2015

Corn Characterization And Development Of A Convenient Laboratory Scale Alkaline Cooking Process, Shreya N. Sahasrabudhe

Dissertations, Theses, & Student Research in Food Science and Technology

Nixtamalized (alkaline cooked) corn (Zea mays L.) products are increasing in popularity due to their affordable cost, ease of production, and the diversity of products that can be made using similar unit operations. The nixtamal produced after alkaline cooking depends on the processing parameters used during cooking and steeping, as well as the physicochemical properties of the corn hybrids used. Processors incur high costs in narrowing down hybrids suitable for a given process, or they must be able to adjust cooking conditions to obtain the desired end-product characteristics. Improper processing generates large quantities of waste. Researchers have developed small scale ...


Viability Of Lactobacillus Acidophilus Dds 1-10 Encapsulated With An Alginate-Starch Matrix, Liya Mo May 2015

Viability Of Lactobacillus Acidophilus Dds 1-10 Encapsulated With An Alginate-Starch Matrix, Liya Mo

Dissertations, Theses, & Student Research in Food Science and Technology

L. acidophilus DDS1-10 was encapsulated using an alginate, potato starch and type 4 resistant starch (RS4) matrix. The wall material was optimized by varying levels of alginate (1.6 to 4.4%), while maintaining potato starch and RS4 ratio fixed at 2, and the total solid content at 5%. Particles were prepared using an emulsion and an extrusion method. Particles obtained from the emulsion method were smaller with a non-uniform distribution in size while those obtained by the extrusion method were bigger and uniform in size. The emulsion method did not seem to offer protection to the probiotic cells against ...


A Finite Element Method Based Microwave Heat Transfer Modeling Of Frozen Multi-Component Foods, Krishnamoorthy Pitchai Apr 2015

A Finite Element Method Based Microwave Heat Transfer Modeling Of Frozen Multi-Component Foods, Krishnamoorthy Pitchai

Dissertations, Theses, & Student Research in Food Science and Technology

Microwave heating is fast and convenient, but is highly non-uniform. Non-uniform heating in microwave cooking affects not only food quality but also food safety. Most food industries develop microwavable food products based on “cook-and-look” approach. This approach is time-consuming, labor intensive and expensive and may not result in optimal food product design that assures food safety and quality. Design of microwavable food can be realized through a simulation model which describes the physical mechanisms of microwave heating in mathematical expressions. The objective of this study was to develop a microwave heat transfer model to predict spatial and temporal profiles of ...


Improving The Health Impacts Of Whole Grains Through Processing: Resistant Starch, Dietary Fiber Solubility, And Mineral Bioaccessibility, Jennifer A. Arcila Castillo Dec 2014

Improving The Health Impacts Of Whole Grains Through Processing: Resistant Starch, Dietary Fiber Solubility, And Mineral Bioaccessibility, Jennifer A. Arcila Castillo

Dissertations, Theses, & Student Research in Food Science and Technology

Whole grains are good sources of starch, dietary fiber, and mineral elements. Starch is an important source of energy but also can be transformed to resistant starch to impart lower caloric value and increase total dietary fiber. Dietary fibers impart physiological benefits to human body once they are fermented by the gut microbiota. Mineral elements are important co-factors of a wide range of enzymes involved for instance in glucose and lipid metabolism. In general human body is capable of absorbing only 21-28% of most mineral elements, and gut bacteria are only able to ferment 34% of the dietary fiber from ...


Characterization Of Commercial Probiotics: Antibiotic Resistance, Acid And Bile Resistance, And Prebiotic Utilization, Carmen Lucia Cano Roca Aug 2014

Characterization Of Commercial Probiotics: Antibiotic Resistance, Acid And Bile Resistance, And Prebiotic Utilization, Carmen Lucia Cano Roca

Dissertations, Theses, & Student Research in Food Science and Technology

Probiotics, live microorganisms that beneficially affect the health of their host, must undergo extensive research to ensure they are safe for consumption and possess certain functional properties. Antibiotic resistance in probiotics has raised concern due to the possibility of its transfer to pathogens. Acid and bile tolerance ensures that organisms will survive passage into the intestines. Prebiotic utilization indicates ability to ferment specific carbohydrates for enhanced growth. The objective of this study was to characterize a group of commercial probiotics for their suitability as probiotics.

Nine commercial probiotic strains (7 Lactobacillus, 1 Lactococcus lactis, and 1 Bifidobacterium longum) were evaluated ...


Adherence Inhibition Of Human Pathogens Campylobacter Jejuni And Campylobacter Coli By Non-Digestible Oligosaccharides, Alejandra Ramirez-Hernandez Jul 2014

Adherence Inhibition Of Human Pathogens Campylobacter Jejuni And Campylobacter Coli By Non-Digestible Oligosaccharides, Alejandra Ramirez-Hernandez

Dissertations, Theses, & Student Research in Food Science and Technology

Adherence is the first and one of the most important steps of bacterial pathogenesis. Natural derived components that inhibit the adherence of pathogens to the surface of epithelial cells have received considered interest. The goal of this research was to assess the anti-adherence activity of mannan oligosaccharides (MOS), pectic oligosaccharides (POS) and cranberry high molecular weight component (HMW) against Campylobacter jejuni and Campylobacter coli. First the anti-adherence activity of MOS and their purified fraction (pMOS) was tested against three strains of C. jejuni and two strains of C. coli. Results shown significant reductions in adherence (up to 70%) of all ...


Understanding The Factors Affecting Microbiological Quality Of Wheat Milled Products: From Wheat Fields To Milling Operations, Luis E. Sabillón Galeas Jul 2014

Understanding The Factors Affecting Microbiological Quality Of Wheat Milled Products: From Wheat Fields To Milling Operations, Luis E. Sabillón Galeas

Dissertations, Theses, & Student Research in Food Science and Technology

Although regarded as a low-risk commodity, wheat flour-based mixes have been implicated in several food safety incidents. The present thesis is a compilation of five scientific manuscripts on the effect of weather variation, milling steps and implementation of pre-milling interventions on the microbiological quality and safety of wheat and milled products. The first manuscript is a review of the microbiological quality and safety of wheat-based products. Despite the low water activity, wheat flour may harbor dormant but viable microorganisms, which could lead to safety concerns when flour is used to produce refrigerated dough products. The second manuscript illustrates the effect ...


Non-Digestible Oligosaccharides: Anti-Adherence And Other Biological Properties, Maria I. Quintero-Villegas Jul 2014

Non-Digestible Oligosaccharides: Anti-Adherence And Other Biological Properties, Maria I. Quintero-Villegas

Dissertations, Theses, & Student Research in Food Science and Technology

Bacterial adherence is the first and one of the most important steps in bacterial pathogenesis. Adherence to host cell surfaces requires that the bacteria recognize specific receptors in the surface of epithelial cells. Therefore, agents that act as molecular decoys to interfere with adherence could be useful prophylactic treatments to prevent or mitigate the onset of infections. The goal of this research was to assess the ability of several food grade non-digestible oligosaccharides (NDOs) to act as molecular decoys and prevent bacterial adherence in vitro as well as in vivo. First, the antiadherence effect of specific species chitooligosaccharides (CHOS) at ...


Starch-Pectin Matrices For Encapsulation Of Ascorbic Acid, Yiwei Liu May 2014

Starch-Pectin Matrices For Encapsulation Of Ascorbic Acid, Yiwei Liu

Dissertations, Theses, & Student Research in Food Science and Technology

Starch and pectin are two food-grade carbohydrates widely utilized in the food industry. Starch and pectin polymers have been investigated in encapsulating functional food ingredients and in pharmaceutical applications. Resistance to enzyme hydrolysis, differential solubilities, depending on the pH, and the ability to ‘protect’ unstable molecules are considered some of the beneficial properties of starch and pectin polymers, for encapsulation applications. Food ingredients could be delivered in a controlled manner to a specific target by encapsulating in micro-scale particles, i. e., microencapsulation. Two studies were conducted to investigate the ability of selected starch-pectin blends in microencapsulating ascorbic acid (vitamin C ...


Tracking Heat-Resistant, Sporeforming Bacteria In The Milk Chain: A Farm To Table Approach, Maricarmen Estrada Anzueto Apr 2014

Tracking Heat-Resistant, Sporeforming Bacteria In The Milk Chain: A Farm To Table Approach, Maricarmen Estrada Anzueto

Dissertations, Theses, & Student Research in Food Science and Technology

Sporeforming bacteria (such as Bacillus and Paenibacillus spp.) can survive pasteurization conditions (Collins, 1981) and grow in pasteurized fluid milk during refrigerated storage (Huck et al., 2008; Ivy et al., 2012), causing fluid milk spoilage and limiting the further extension of fluid milk’s shelf life (Fromm and Boor, 2004; Durak et al., 2006). Moreover, Bacillus and related genera have been found in raw milk, pasteurized milk and environmental samples from dairy farms, indicating that these organisms are ubiquitous in nature and can enter the milk chain from different sources (Huck et al., 2007b; Huck et al., 2008; Ranieri and ...


Characterization Of Extraction Methods To Recover Phenolic Rich Extracts From Pinto Beans That Exert High Antioxidative Activities Using Response Surface Approach, Mohammed Aldawsari Apr 2014

Characterization Of Extraction Methods To Recover Phenolic Rich Extracts From Pinto Beans That Exert High Antioxidative Activities Using Response Surface Approach, Mohammed Aldawsari

Dissertations, Theses, & Student Research in Food Science and Technology

The pinto bean has been linked to the prevention of multiple diseases due in large part to the presence of phenolic antioxidants, which are higher in beans than in many fruits and vegetables. These components deliver health properties beyond basic nutritional characteristics by scavenging free oxygen radicals. However, these benefits are most likely due to the ability of these chemically diverse phenols to impart greater protective properties as additives or synergists acting in combination. However, optimal parameters to isolate these compounds (in terms of ratios and types) from a given natural source are not known. Without this knowledge, understanding the ...


Debaryomyces Hansenii: A Foodborne Yeast That Produces Anti-Candida Killer Toxin, Nabaraj Banjara Apr 2014

Debaryomyces Hansenii: A Foodborne Yeast That Produces Anti-Candida Killer Toxin, Nabaraj Banjara

Dissertations, Theses, & Student Research in Food Science and Technology

Candida yeasts are commensal members of the gastrointestinal, mucosal, oral and vaginal microbiota. Candida albicans and C. tropicalis can be found as a part of the normal human commensal flora, especially in all sections of the gastrointestinal tract. However, when the host defense system and microbiota are disturbed, Candida can become pathogenic and cause severe infection or candidiasis. Antifungal drugs used to treat candidiasis have been shown to result in treatment failures due to drug toxicity and/or development of resistance during long term antifungal therapy and, in recent years, the incidence of Candida infections has increased dramatically due to ...


Development Of An Enzyme-Linked Immunosorbent Assay (Elisa) For The Detection Of Pecan Residues In Processed Foods, Denise Tran Aug 2013

Development Of An Enzyme-Linked Immunosorbent Assay (Elisa) For The Detection Of Pecan Residues In Processed Foods, Denise Tran

Dissertations, Theses, & Student Research in Food Science and Technology

Pecan nuts are becoming increasingly popular due to their link to health benefits. However, the presence of undeclared pecan residues in food products can pose serious health risks for pecan-allergic consumers. Currently, analytical methods for the detection of pecan allergens are limited and have not been validated for use by the food industry to assess the effectiveness of allergen control programs. Therefore, the aim of this study was to develop a sandwich-type ELISA to detect and quantify allergenic pecan residues in processed foods. Several varieties of pecan were mixed, roasted, and ground to immunize a goat, sheep, and rabbits. The ...


Characterization Of The Gut Microbiota And Colitogenic Bacterial Species In Core 1 O-Glycans Deficient Mice, Maria E. Perez-Munoz Jul 2013

Characterization Of The Gut Microbiota And Colitogenic Bacterial Species In Core 1 O-Glycans Deficient Mice, Maria E. Perez-Munoz

Dissertations, Theses, & Student Research in Food Science and Technology

Mucus is one important component of the intestinal mucosal barrier, and loss of its functionality is associated with colitis in humans and mice. Mice deficient in core 1 O-glycans (TM-IEC C1galt1-/-) display a thinner mucus layer upon mutation of the glycosyltransferase enzyme (C1GALT1) responsible for core 1 O-glycans attachment, thus constituting an experimental model for human Ulcerative Colitis (UC). Under conventional conditions, these mice experience spontaneous inflammation of the colon. However, the exact role of the microbiota in colitis development in these mice has not been systematically investigated.

Aimed to gain insights into the role of the microbiota ...


Risk Assessment Of Trace And Undeclared Allergens In Processed Foods, Benjamin C. Remington May 2013

Risk Assessment Of Trace And Undeclared Allergens In Processed Foods, Benjamin C. Remington

Dissertations, Theses, & Student Research in Food Science and Technology

Minimal eliciting doses for objective allergic reactions were found for 13 priority allergens and over 1800 individuals from published clinical literature or unpublished clinical data. Allergic populations did not vary when analyzed by age or geographic region. Results of this study show there are sufficient clinical data from food allergic individuals to use for risk assessment purposes for several allergenic foods.

Of 186 food products bearing advisory statements regarding peanut or 16 products that had peanut listed as a minor ingredient, 8.6% and 37.5% contained detectable levels of peanut (>2.5 ppm whole peanut). An additional market survey ...


Validation Of Microwave Heating Instructions For The Destruction Of Salmonella Spp. In Microwaveable Foods, Carol J. Valenzuela Apr 2013

Validation Of Microwave Heating Instructions For The Destruction Of Salmonella Spp. In Microwaveable Foods, Carol J. Valenzuela

Dissertations, Theses, & Student Research in Food Science and Technology

Microwave heating instructions for three products (chicken nuggets, turkey pot-pies and mashed potato) were developed and validated based on end point temperatures using two microwave ovens (2,459 MHz; 700 W and 1,350 W). Heating instructions for chicken nuggets were validated using different configuration of product placement (edge or center of the carousel) and number of units (4, 6 and 8). Salmonella spp. reductions of 6.56 log CFU/g (700 W) were observed in chicken nuggets heated in groups of 4 and placed at the center of the carousel with 1 min 26 s of heating time with ...


Characterization Of Starch By Vibrational Spectroscopy, Brandon H. Holder Dec 2012

Characterization Of Starch By Vibrational Spectroscopy, Brandon H. Holder

Dissertations, Theses, & Student Research in Food Science and Technology

To develop a dispersive Raman spectroscopic method for measuring amylose-amylopectin ratios of corn starch mixtures, 67 mixtures were prepared by randomly mixing waxy and normal corn starches. Amylose contents were measured using a dual wavelength iodine binding colorimetric method. Raman data were collected from 250 to 3200 cm-1 using optimized instrument parameters. Partial least-squares (PLS) and principal components regression (PCR) were used to prepare multivariate calibration models; however, PLS commonly outperformed PCR. Truncating the spectra to 250 to 2000 cm-1 improved the results (r2 of validation = 0.831, SEP = 2.90%). Removal of a cold water swelling ...


New Technologies For Whole Wheat Processing: Addressing Milling And Storage Issues, Andres F. Doblado-Maldonado Nov 2012

New Technologies For Whole Wheat Processing: Addressing Milling And Storage Issues, Andres F. Doblado-Maldonado

Dissertations, Theses, & Student Research in Food Science and Technology

Whole wheat flour production and demand has increased dramatically during the last decade due to evidence supporting the benefits of whole grains in the diet. Hence, the food industry has provided a wide variety of new whole grain products. There are unique challenges that accompany whole wheat flour production, especially related to milling and storage. The present thesis provides new strategies on the adaptation of new technologies to overcome whole wheat processing issues. These issues are first discussed in a literature review and then followed by three research studies. In the first study, retail whole wheat flours were evaluated for ...


The Evolution Of Host Specificity In The Vertebrate Gut Symbiont Lactobacillus Reuteri, Steven Frese Nov 2012

The Evolution Of Host Specificity In The Vertebrate Gut Symbiont Lactobacillus Reuteri, Steven Frese

Dissertations, Theses, & Student Research in Food Science and Technology

The vertebrate gut is home to one of the densest populations of life on Earth. This microbial community has a profound effect on host health, nutrition, development, behavior, and evolution. However, very little is known about how these microbes have evolved with their vertebrate hosts, how and whether they select hosts or how they remain associated with their hosts. Recent work identified Lactobacillus reuteri as an organism that is composed of host-specific sub-populations, each population associated with a different host animal. Representatives from each host-associated population were tested for their ability to colonize gnotobiotic mice, which only rodent strains could ...


Evidence Of Transmission Of Escherichia Coli O157:H7 To The Tissues Or Phyllo-Plane Of Wheat, From Contaminated Soil, Seeds Or Water, Bismarck Antonio Martinez Nov 2012

Evidence Of Transmission Of Escherichia Coli O157:H7 To The Tissues Or Phyllo-Plane Of Wheat, From Contaminated Soil, Seeds Or Water, Bismarck Antonio Martinez

Dissertations, Theses, & Student Research in Food Science and Technology

Escherichia coli O157:H7 is a human pathogen that can cause a wide spectrum of disease symptoms, such as bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Escherichia coli O157:H7 illness are mainly associated with undercooked beef; however, in recent years outbreaks have been linked to fresh produce such as spinach, lettuce, and sprouts. In 2009, flour was implicated as a contamination source in the consumption of raw cookie dough resulting in 77 illness-cases. The objective of this research was to determine the possible route of transmission of E. coli O157:H7 into the phyllo-plane of wheat using ...


Analysis Of Microbial Diversity By Amplicon Pyrosequencing, Ryan Legge Aug 2012

Analysis Of Microbial Diversity By Amplicon Pyrosequencing, Ryan Legge

Dissertations, Theses, & Student Research in Food Science and Technology

Microorganisms numerically dominate terrestrial biodiversity, and play important biochemical and geochemical roles in the environments they inhabit. To understand structure and function of complex ecosystems, it is essential to identify primary drivers of microbial diversity and community structure. Historically, the study of microbial ecology was reductive, limited to microbes able to be cultured and enumerated. Microbes meeting this criterion were thought to comprise the dominating members of the environments they were isolated from, however, estimates suggesting up to 99% of the endogenous species are uncultivable with existing methodologies; a concept that reflects experimental failure, rather than a verifiable conclusion. Therefore ...