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Pro- And Antioxidant Effects Of Phospholipids On Lipid Oxidation In Bulk Oil, Leqi Cui Nov 2015

Pro- And Antioxidant Effects Of Phospholipids On Lipid Oxidation In Bulk Oil, Leqi Cui

Doctoral Dissertations

The aim of this thesis is to explore how phospholipids at concentrations similar as in refined vegetable oils impact bulk oil lipid oxidation. The possible formation of association colloids and synergism with primary antioxidants are considered. The results provided a better understanding of the pro- and antioxidant activities of phospholipids.

Lipid oxidation leads to quality deterioration by generating off-flavor, nutrient loss, color alteration, texture changes, and even generation of potential toxic products. Phospholipids are important minor components in edible oil that play a role in lipid oxidation. Surface active phospholipids have an intermediate hydrophilic–lipophilic balance value, which allows them ...


Role Of Lipid-Based Delivery Systems In The Biological Fate Of Lipophilic Nutraceuticals And Inorganic Nano-Particles In The Gastrointestinal Tract, Mingfei Yao Nov 2015

Role Of Lipid-Based Delivery Systems In The Biological Fate Of Lipophilic Nutraceuticals And Inorganic Nano-Particles In The Gastrointestinal Tract, Mingfei Yao

Doctoral Dissertations

The oral bioavailability of lipophilic bioactive molecules can be greatly increased by encapsulating them within engineered lipid nanoparticles, such as micelles, microemulsions and nanoemulsions. After ingestion these engineered lipid nanoparticles are disassembled in the gastrointestinal tract (GIT), and then reassembled into biological lipid nanoparticles (mixed micelles) in the small intestine. These mixed micelles solubilize and transport lipophilic bioactive components to the epithelium cells. The mixed micelles themselves are then disassembled and reassembled into yet another form of biological lipid nanoparticle (chylomicrons, CMs) within the enterocyte cells. The CMs carry the bioactive components into the systemic (blood) circulation via the lymphatic ...


Effects Of Conjugated Linoleic Acid (Cla) On Skeletal Muscle Metabolism, Yoo Kim Nov 2015

Effects Of Conjugated Linoleic Acid (Cla) On Skeletal Muscle Metabolism, Yoo Kim

Doctoral Dissertations

Although it is well known that increased physical activity can help reduce incidences of obesity, physical activity can be influenced by complex issues, making it difficult to use universal means to control obesity. Recent discoveries of the effects of exercise at the cellular level opened up the unique opportunity to develop compounds with ‘exercise-like’ effects. In fact, CLA has been shown to promote voluntary activity and endurance capacity in mice. Thus, the purpose of these studies is to determine the mechanisms of conjugated linoleic acid on muscle metabolism via the modulation of biochemical events including mitochondrial biogenesis and the alternation ...


Structural Design Approaches For Creation Of Reduced Fat Products, Bicheng Wu Nov 2015

Structural Design Approaches For Creation Of Reduced Fat Products, Bicheng Wu

Doctoral Dissertations

In awake of the health issues related with high-calorie diet, there was a strong focus in the development of reduced-fat products in the food industry. However, fat plays an important role in determining the quality attributes of food products such as texture, appearance, flavor and stability, therefore there has been limited success for reduced-fat products. This thesis project thus targeted liquid and semi-solid products such as dressings, sauces, and aimed to address problems associated with low-fat by utilizing structural designed approach.

The first part of this project focused on using controlled aggregation of protein-stabilized lipid droplets to regulate the microstructure ...


Physicochemical And Toxicological Assessment Of Antimicrobial Ε-Polylysine-Pectin Complexes, Cynthia L. Lopez Pena Aug 2015

Physicochemical And Toxicological Assessment Of Antimicrobial Ε-Polylysine-Pectin Complexes, Cynthia L. Lopez Pena

Doctoral Dissertations

ε-Polylysine is an appealing FDA-approved, all natural antimicrobial biopolymer effective against a wide range of microorganisms. Its implementation is greatly limited by its strong cationic charge, which has been linked to instability in food systems, perceived astringency and bitterness, and the ability to inhibit lipid digestion. Previous studies have shown that controlled complexation of ε-polylysine with anionic pectin is able to prevent instability and astringency in simplified model food systems, while maintaining the antimicrobial character of polylysine. Isothermal titration calorimetry, micro-electrophoresis, microscopy, and turbidity analyses of the stability of electrostatic pectin-polylysine complexes in the presence of strongly anionic κ-carrageenan, and ...


Improving Antimicrobial Activity Of Lauric Arginate By Combination With Essential Oils For Novel Applications, Qiumin Ma Aug 2015

Improving Antimicrobial Activity Of Lauric Arginate By Combination With Essential Oils For Novel Applications, Qiumin Ma

Doctoral Dissertations

Lauric arginate (LAE) and essential oils (EOs) are highly efficacious in broth media but are required at much higher concentrations in food products to inhibit foodborne pathogens. Because high levels of LAE and EOs affect organoleptic properties of food products, this dissertation was studied for the potential of lowering their usage concentrations by using them in combination. Antimicrobial activities of LAE and EO used alone or in combination were characterized in Chapter 2. Synergistic and antagonistic effects of LAE-EO combinations and cinnamon leaf oil/eugnol/thymol were observed for inhibiting Gram-positive Listeria monocytogenes and Gram-negative Salmonella Enteritidis and Escherichia coli ...


Self-Assembled Casein Nanostructures To Deliver Novel Functionalities, Kang Pan Aug 2015

Self-Assembled Casein Nanostructures To Deliver Novel Functionalities, Kang Pan

Doctoral Dissertations

The nanoscale micellar structure of caseins can be manipulated by mechanical forces, solvent quality, and pH to reduce turbidity, encapsulate hydrophobic compounds, and improve dispersion stability and rheological properties. The goal of this dissertation was to control the nanostructure of self-assembled caseins to deliver functionalities. The combination of treatments at pH 11.0 and acidification with citric acid was first studied to produce translucent skim milk dispersions at pH 5.5-7.0, resulting from the significantly reduced dimensions of reassembled casein nanoparticles. Using sodium caseinate (NaCas), soluble soybean polysaccharide (SSPS), and high-speed homogenization, a food grade delivery system was studied ...


Salmonella In Low Water Activity Foods: Physiological, Genetic Modification And Control Methods, Wei Chen Aug 2015

Salmonella In Low Water Activity Foods: Physiological, Genetic Modification And Control Methods, Wei Chen

Doctoral Dissertations

The objective of this study was to evaluate the expression of fatty acid associated genes (fabA, fabD and cfa) of five serovars of Salmonella exposed to sugar over a 14-day period. Changes in the fatty acid composition of Salmonella Tennessee in glycerol solutions of different water activity (aw) (1.0-0.6) and the relationship between survival and fatty acid modification (as altered by exogenously supplied fatty acids) at aw 1.0-0.6 were also determined. Furthermore, the antimicrobial activities of carvacrol, cinnamaldehyde, and lauric arginate (LAE) alone or in combination against Salmonella Tennessee in a laboratory model of ...


Blueberry Polyphenols As Natural Antimicrobial Agents Against Foodborne Viruses: Towards Understanding Their Mechanism And Applications In Food Systems, Snehal Shrikant Joshi Aug 2015

Blueberry Polyphenols As Natural Antimicrobial Agents Against Foodborne Viruses: Towards Understanding Their Mechanism And Applications In Food Systems, Snehal Shrikant Joshi

Doctoral Dissertations

Foodborne viruses are recognized as public health concerns worldwide and therefore effective strategies to control their spread are being researched. Blueberries are known for their health benefits and antimicrobial properties. This study aimed to (1) determine the antiviral effects of blueberry juice (BJ) and blueberry proanthocyanidins (B-PAC) against the infectivity of hepatitis A virus (HAV), Aichi virus (AiV) and human norovirus surrogates (feline calicivirus (FCV-F9) and murine norovirus (MNV-1)) at 37oC over 24-h using standard plaque assays; (2) evaluate antiviral effects in model foods (apple juice (AJ) and 2% milk) and simulated gastrointestinal conditions at 37oC ...


Thermal Inactivation Of Shiga Toxin-Producing Escherichia Coli In Foods, Malcond David Valladares May 2015

Thermal Inactivation Of Shiga Toxin-Producing Escherichia Coli In Foods, Malcond David Valladares

Doctoral Dissertations

Emerging non-O157 Shiga toxin-producing Escherichia coli (STEC) were recently added to the zero tolerance policy by the USDA-FSIS. Therefore, the precise characterization of their thermal inactivation kinetics in different foods and the effect of stress on thermal inactivation are needed. This research aimed at determining the heat inactivation kinetics of non-O157 and O157 STECs in buffer and model food matrices and the effects of DnaK levels on thermal resistance after acid and heat-shock. Thermal inactivation was carried out in either in 2-ml glass vials or nylon vacuum-sealed bags for buffer and food (spinach, ground-beef, turkey deli-meat, pasta) samples, respectively. Vials ...


Rationalizing Nanoemulsion Formation For Encapsulation, Protection And Delivery Of Bioactive Food Components, Ying Yang Mar 2015

Rationalizing Nanoemulsion Formation For Encapsulation, Protection And Delivery Of Bioactive Food Components, Ying Yang

Doctoral Dissertations

The objective of this thesis was to design and develop novel food-grade nanoemulsion-based delivery systems for the encapsulation, protection and delivery of lipophilic bioactive food components. These delivery systems could be widely applied in aqueous-based fortified food products, such as beverages, salad dressing and yogurt etc.

Both the low- and high-energy methods could be used for fabricating nanoemulsions (r < 100 nm). The microfluidization method could form nanoemulsions at low surfactant-to-oil ratios (SOR < 0.1), but it required the use of high-energy inputs and expensive equipment. On the other hand, the spontaneous emulsification method could also form ultrafine emulsions and moreover it was simple and inexpensive, but it required much higher surfactant-to-oil ratios (SOR > 0.5) for forming nanoemulsions.

Q-Naturale® is a natural food-grade surfactant, which is got from the bark of the Quillaja saponaria Molina tree. By using high pressure homogenization (microfluidization), Q-Naturale® could form relatively small droplets (d < 200 nm) at low surfactant-to-oil ratios (SOR < 0.1), but the droplets were not as small as those produced using Tween 80 under similar conditions (d < 150 nm). The emulsions formed by using Q-Naturale® as the emulsifier were ...


Experimental And Modeling Studies On The Formulation Of Stable Lipid Nanoparticle Dispersions, Yihui Yang Mar 2015

Experimental And Modeling Studies On The Formulation Of Stable Lipid Nanoparticle Dispersions, Yihui Yang

Doctoral Dissertations

This thesis presents both experimental and modeling studies on the formulation of stable lipid nanoparticle dispersions. A population balance equation (PBE) model was developed for prediction of the average polymorph content and aggregate size distribution to better understand the undesirable SLN aggregation behavior. Experimental and modeling studies showed that the polymorphic transformation was the rate determining step for my system, SLNs with smaller initial size distributions aggregated more rapidly, and aggregates contained particles with both alpha and beta crystals. Next the effect of different liquid carrier oils on the crystallization and aggregation behavior of tristearin NLC dispersions was investigated. I ...


Prediction Of Emulsion Drop Size Distributions With Population Balance Equation Models To Enable Emulsified Product Design, Shashank Maindarkar Mar 2015

Prediction Of Emulsion Drop Size Distributions With Population Balance Equation Models To Enable Emulsified Product Design, Shashank Maindarkar

Doctoral Dissertations

Oil-in-water emulsions are ubiquitous dispersed phase systems with diverse applications in consumer products, processed foods, and the pharmaceutical industry. Emulsion formulation variables and process operating conditions both impact the drop size distribution, a key property that influences emulsion rheology, stability, texture, and appearance. A typical emulsified product requires the drop size distribution to be maintained within acceptable limits. Due to a lack of quantitative understanding, emulsified products are currently manufactured by combining a broad knowledge of previous product formulations with empirical scientific experimentation. An alternative to trial-and-error experimentation is to utilize a suitable mathematical model to predict the drop size ...


Layer-By-Layer Antimicrobial N-Halamine Polymer Coatings For Food Contact Materials, Luis J. Bastarrachea Gutierrez Mar 2015

Layer-By-Layer Antimicrobial N-Halamine Polymer Coatings For Food Contact Materials, Luis J. Bastarrachea Gutierrez

Doctoral Dissertations

Cross contamination during food processing represents a risk for public health and financial burden. Surface modification of food contact materials to render them antimicrobial can be effective against such risk. The objective of the present work was to develop antimicrobial coatings with the potential to be applied in a variety of food contact materials. The polymer coatings developed became antimicrobial by incorporation of a type of chlorinated compounds called N-halamines, capable of regenerating their antimicrobial activity.

Two layer-by-layer (LbL) assembly surface modification procedures were followed. In the first procedure, bilayers of branched polyethyleneimine (PEI) and poly(acrylic acid) (PAA) were ...


Absorption And Utilization Of Choline And Vitamin B12 In Lactating Dairy Cows Using Different Delivery Methods, Virginia Maria Artegoitia Etcheverry Dec 2014

Absorption And Utilization Of Choline And Vitamin B12 In Lactating Dairy Cows Using Different Delivery Methods, Virginia Maria Artegoitia Etcheverry

Doctoral Dissertations

Choline and vitamin B12 are essential nutrients for growth and performances of production animals. However, both nutrients are extensively degraded during digestion in the rumen. This thesis comprised three experiments. First, four cows equipped with a rumen cannula and catheters in the portal vein and a mesenteric artery received a post-ruminal bolus of: 1) cyanocobalamin (CN-CBL) alone (0.1 g) [gram], 2) CN-CBL (0.1 g) + casein (10 g) or 3) CN-CBL (0.1 g) + whey proteins (10 g). After the bolus, blood samples were taken until 24 h [hour] post-bolus. The intestinal absorption of CN-CBL was greater when the ...


An Epidemiological Study Of Campylobacter Populations Reveals A Selective Pressure By Roxarsone, Sean Jeffery Pendleton Dec 2014

An Epidemiological Study Of Campylobacter Populations Reveals A Selective Pressure By Roxarsone, Sean Jeffery Pendleton

Doctoral Dissertations

Whole genome sequencing (WGS) is the most discriminatory of typing methods and can provide additional information including virulence, antigen targets for vaccine development, and antimicrobial resistance profiles. The first part of this study aimed to determine the application of WGS as a genotyping method for Campylobacter by comparing WGS to two commonly used genotyping methods, Pulsed-field gel electrophoresis (PFGE) and flaA typing. Five Campylobacter strains isolated from conventional and organic poultry, and five additional isolates with published genomes were compared using the three methods. A total of 8 PFGE patterns and 8 flaA alleles were identified from the 10 strains ...


Impact Of Surface Active Minor Components On Physicochemical Properties Of Association Colloids And Lipid Oxidation In Bulk Oil, Ketinun Kittipongpittaya Nov 2014

Impact Of Surface Active Minor Components On Physicochemical Properties Of Association Colloids And Lipid Oxidation In Bulk Oil, Ketinun Kittipongpittaya

Doctoral Dissertations

Lipid oxidation is a great concern for food manufacturers and consumers as it negatively impacts not only food quality and nutritive values of food lipids, but also consumer health. Lipid oxidation in bulk oil is impacted by chemical factors, such as, prooxidants and antioxidants, and is also related to the existence of physical structures. Bulk oils contain a variety of surface active minor components which are able to form physical structures known as association colloids. These physical structures create oil-water interfaces which seem to be an important site where lipid oxidation occurs in bulk oil. Thus, this research focused on ...


Influence Of Lipoteichoic Acid On Listeria Monocytogenes Biofilm Formation And Cellular Stress, Imelda T. Brooks Nov 2014

Influence Of Lipoteichoic Acid On Listeria Monocytogenes Biofilm Formation And Cellular Stress, Imelda T. Brooks

Doctoral Dissertations

Lipoteichoic acid (LTA) is an important polymer on the surface of Gram-positive organisms, including the foodborne, biofilm-forming pathogen Listeria monocytogenes, and is connected to the cell membrane through a glycolipid backbone. Previous results have shown the importance of LTA in cell viability and biofilm formation. The purpose of this research is to further investigate the influence of LTA in L. monocytogenes biofilm formation and how the bacterium responds to environmental stress caused by antimicrobial exposures, and a combination of low temperature and high osmolarity. We created in frame deletion mutants along the operon lmo-2555-lmo2554-lmo2553, which have been shown to reduce ...


Understanding Lipid Oxidation In Low-Moisture Food, Leann M. Barden Nov 2014

Understanding Lipid Oxidation In Low-Moisture Food, Leann M. Barden

Doctoral Dissertations

Low-moisture snacks account for much of the saturated fat in the diet, making them a key target for improving consumers’ health. However, it is not currently feasible to maintain the same shelf life when replacing saturated fats with unsaturated fats in these products.

The first study characterized the microstructure of a low-moisture cracker model system and determined the impact of iron, chelators, and free fatty acids (FFA) on lipid oxidation kinetics. Confocal microscopy showed that lipids form a continuous layer surrounding the small and/or minimally gelatinized starch granules. Lipid-starch, lipid-air, and starch-lipid-protein interfaces all existed. Oxidation studies showed a ...


Susceptibility Of Escherichia Coli O157:H7, Salmonella Enterica Sp., And Listeria Monocytogenes To Antimicrobial Mixed Micelle Delivery Systems, Chanelle N. Adams Nov 2014

Susceptibility Of Escherichia Coli O157:H7, Salmonella Enterica Sp., And Listeria Monocytogenes To Antimicrobial Mixed Micelle Delivery Systems, Chanelle N. Adams

Doctoral Dissertations

Within the food industry, there is an ever increasing demand to improve the quality of food and ensure safety from pathogenic/spoilage microorganisms. Globalization of the food industry in the 1990’s, in conjunction with the worldwide shipment of food created a need for the extension of shelf-life and enhanced maintenance of food quality (12). In the United States alone, the Centers for Disease Control and Prevention report that each year, roughly 1 in 6 Americans (or 48 million people) gets sick, 128,000 are hospitalized, and 3,000 die of foodborne diseases; this correlates to approximately $77.7 billion ...


Cancer Chemoprevention By Dietary Compounds Targeting Angiogenesis, Wasamon Nutakul Aug 2014

Cancer Chemoprevention By Dietary Compounds Targeting Angiogenesis, Wasamon Nutakul

Doctoral Dissertations

Cancer remains a leading cause of death worldwide. Due to angiogenesis and metastatic potency of cancer, chemotherapies are not adequate for metastatic tumor. We investigated anti-carcinogenic effects of resveratrol in comparison to those of pterostilbene in colon cancer cells. We found superior activities of pterostilbene over resveratrol in growth inhibition as well as apoptosis induction. Higher Intracellular concentration of pterostilbene could contribute to its higher potency in anti-carcinogenesis; however, both resveratrol and pterostilbene failed to inhibit colon cancer cell migration in vitro. Polymethoxylatedflavones (PMFs) found exclusively in citrus fruits have shown inhibitory effects against cancer. We investigated their anti-angiogenic activities ...


Fabrication Of Zein Nanoparticle-Biopolymer Complexes To Deliver Essential Oils In Aqueous Dispersions, Huaiqiong Chen Aug 2014

Fabrication Of Zein Nanoparticle-Biopolymer Complexes To Deliver Essential Oils In Aqueous Dispersions, Huaiqiong Chen

Doctoral Dissertations

Zein, alcohol-soluble corn proteins, easily precipitate as nanoparticles after dispersing a stock zein solution with a polar solvent into water. The process can be used to nanoencapsulate essential oils (EOs). However, the stability of hydrophobic zein nanoparticles is a challenge for their application in aqueous food systems. The goal of this dissertation reseach was to stabilize zein nanoparticles in aqueous dispersions by forming complexes with water-soluble biopolymers. The stabilization of zein nanoparticles was first studied using sodium caseinate by dispersing hot 50% aqueous ethanol solution with both polymers in water. The nanoparticles contained κ-casein and zein, and the spray-dried nanoparticles ...


Casein Micelles And Their Properties: Polydispersity, Association With Vitamin A And Effect Of Ultra-High Pressure Homogenization, Maneesha Sheenu Mohan Aug 2014

Casein Micelles And Their Properties: Polydispersity, Association With Vitamin A And Effect Of Ultra-High Pressure Homogenization, Maneesha Sheenu Mohan

Doctoral Dissertations

The internal structure of casein micelles is not fully understood. In the present work, we explore some of the basic questions about casein micelles in bovine milk including its size distribution, native binding properties and effect of ultra-high pressure homogenization (ultra-HPH) on technological properties of casein micelles. The size distribution of casein micelles was studied by cryo-TEM using skim milk from four cows. The degree of variation in casein micelle sizes (polydispersity) ranged between 0.39 and 0.47 for a size distribution ranging from 10 to 693 nm. These results indicated high polydispersity of casein micelles in milk from ...


Thermal Inactivation Of Human Norovirus Surrogates And Hepatitis A Virus In Foods, Hayriye Bozkurt Cekmer May 2014

Thermal Inactivation Of Human Norovirus Surrogates And Hepatitis A Virus In Foods, Hayriye Bozkurt Cekmer

Doctoral Dissertations

Foodborne enteric viruses are the leading cause of gastroenteritis in humans. In particular, human noroviruses and hepatitis A virus (HAV) are the most important foodborne viral pathogens with regard to the number of outbreaks and people affected. Therefore, studies are needed to bridge existing data gaps and determine appropriate parameters for thermal inactivation methods for human norovirus and hepatitis A virus. Due to the absence of appropriate cell culture systems to propagate these viruses, cultivable surrogates (feline calicivirus, FCV-F9 and murine norovirus, MNV-1) are commonly used based on the assumption that they can mimic the viruses they represent. The objectives ...


Development Of Capillary-Driven Microfludic Biosensors For Food Safety And Quality Assurance, Fei He Apr 2014

Development Of Capillary-Driven Microfludic Biosensors For Food Safety And Quality Assurance, Fei He

Doctoral Dissertations

Rapid detection technologies with high sensitivity and selectivity for pathogenic bacteria are critical in food safety and quality assurance. Traditional laboratory benchtop techniques (i.e. culture and colony counting) are time consuming and require complex sample handling. Microfluidics-based Lab-on-a-Chip (LOC) systems offer a detection alternative where all detection steps are on one portable miniaturized device. The miniaturization of rapid foodborne pathogen detection at a low cost is especially ideal for resource-limited settings or for field-use. The goal of this study was to develop a disposable miniaturized microfluidic device for on-site pathogen detection.

Capillary-driven microfluidics have been introduced in this study ...


Whey Proteins Cross-Linked By Transglutaminase Or Glycated With Maltodextrin: Physicochemical Bases Of The Improved Heat Stability, Wan Wang Dec 2013

Whey Proteins Cross-Linked By Transglutaminase Or Glycated With Maltodextrin: Physicochemical Bases Of The Improved Heat Stability, Wan Wang

Doctoral Dissertations

Whey protein, as a byproduct in cheese manufacturing, is an ideal source for producing ready-to-drink protein beverages for different market demands, attributed to its high content of essential amino acids and versatile functionalities, bland flavor and good digestibility. Whey protein is a mixture of proteins, which can be categorized into whey protein concentrate (WPC) with a protein content of 50~80% and whey protein isolate (WPI) with a protein content higher than 90%, depending on different separation techniques. Thermal processing is required to ensure microbiological safety and quality of dairy products, leading to denaturation of whey proteins, especially at pH ...


Design And Development Of Seed Hydration Analyzing Device And Its Utilization In Studying Cereal And Legume Hydration, Vinay Kumar Mannam Dec 2013

Design And Development Of Seed Hydration Analyzing Device And Its Utilization In Studying Cereal And Legume Hydration, Vinay Kumar Mannam

Doctoral Dissertations

Cereals and legumes are important sources of vegetable-based human nutrition. Together they account for 48.6 % of protein and 8.7 % carbohydrate consumption around the world. During preparation, majority of these agricultural staples are re-hydrated to aid in their digestibility, palatability and the bio-availability of the nutrients.

Study of hydration kinetics of cereals and legumes is an important and valuable necessity for industry and academia to understand and gain insights into seed hydration characteristics. An automatic seed hydration analyzing system is developed as a solution for lack of instruments with broad capabilities to study variety of seed properties. The device ...


Isolation, Antibiotic Resistance, And Molecular Characterization Of Campylobacter From Poultry, Swine And Dairy Cows, Willie James Taylor Dec 2012

Isolation, Antibiotic Resistance, And Molecular Characterization Of Campylobacter From Poultry, Swine And Dairy Cows, Willie James Taylor

Doctoral Dissertations

This study was conducted to determine presence, antibiotic resistance, and genetic relatedness of Campylobacter on diverse farm types. Cloacal fecal samples from poultry (broilers, layers, and turkey breeders), and fecal rectal samples from non-poultry animals (farrowing sows, finisher pigs, and lactating dairy cows) were tested for Campylobacter using BAM protocols. Agar disk diffusion method was used to determine antibiotic resistance, and PFGE analysis to determine genetic relatedness of isolates recovered within the different farm types. Campylobacter was detected in 34.8% (range of 6.7 to 62.0%, P < 0.001) of cloacal samples from poultry, in 61.4% (range of 55.0 to 69.0%, P < 0.05), and 26.0% (range of 19.0 to 34.0%, P < 0.05) of rectal samples from pigs, and dairy cows, respectively. Antibiotic resistance was detected in 30.2% (range of ...


Casein Micelles From Bovine Milk: Native Structure, Interactions, And Practical Applications Of Their Structural Modification, Raymundo Trejo Dec 2012

Casein Micelles From Bovine Milk: Native Structure, Interactions, And Practical Applications Of Their Structural Modification, Raymundo Trejo

Doctoral Dissertations

A definitive structure of the native casein micelle structure continues to elude researchers. Data and images obtained via cryo - transmission electron microscopy of isolated native casein micelles allowed for the reconstruction of a three dimensional model of the micelle; which contains water filled cavities (ca. 20 to 30 nm diameter), channels (diameter larger than ca. 5 nm), and several hundred high density nanoclusters (6-12 nm diameter) within the interior of the micelles.

The SDS polyacrylamide gel electrophoresis of isolated micelles (pH 6.8, 5.0) showed that whey proteins were found associated with the isolated micelles regardless of the pH ...


Novel Rapid Molecular Detection And Processing Approaches For The Control Of Salmonella Enterica Serovars In The Food Environment, Chayapa Techathuvanan May 2012

Novel Rapid Molecular Detection And Processing Approaches For The Control Of Salmonella Enterica Serovars In The Food Environment, Chayapa Techathuvanan

Doctoral Dissertations

The increase in Salmonella enterica outbreaks calls for an urgent need to rapidly detect and control Salmonella-associated contamination. Loop-mediated isothermal amplification (LAMP) assay is a novel method that can be completed within 90 min in a simple waterbath. Detection is by simple turbidity, fluorescence, or gel electrophoresis and is more specific than PCR. Reverse-transcriptase LAMP (RT-LAMP) targeting mRNA for the potential detection of live infectious Salmonella or recent contamination was used in this study and detection sensitivity to culture-based detection and RT-PCR assays was compared in pure culture, food products, and food processing environments. Our results showed detection limits ...