Life Sciences Commons^™

Modeling For Thermal Resistance Of Non-O157 Shiga Toxin Producing Escherichia Coli In Ground Beef, Jagpinder S. Brar

Open Access Dissertations

Predictive models in microbiology are used for estimating the growth or survival of microorganism in a set of environmental conditions. A validated predictive model provides an alternative to extensive survival and shelf life studies. In this study, a predictive inactivation model for non-O157 shiga toxin producing Escherichia coli (STEC) in ground beef was developed. Six strains of non-O157 STEC; E. coli O26:H1, E. coli O45:H2, E. coli O103:H2, E. coli O111:H8, E. coli O121:H9, and E. coli O145: nonmotile, has similar pathogenicity as E. coli O157:H7 and can cause serious food borne illnesses. These pathogens are considered as an adulterant …

Complex Glycan Utilization Preferences Of Human Gut Bacteria, Yunus Emre Tuncil

Open Access Dissertations

Complex glycans, making up dietary fiber, have gained significance in recent years as they are the main energy source for the colonic microbiota which are physiologically important for the host health. Understanding glycan utilization strategies of the members of this community is essential to maximize beneficial health outcomes obtained from them. In order to investigate how the members of our gut microbiota utilize glycans and activate their respective polysaccharide utilization loci (PULs), we performed a series of time-course assays in which two model organisms, Bacteroides thetaiotamicron (Bt) and B. ovatus (Bo), were individually grown in a medium containing carbohydrates utilized …

Prevalence And Antimicrobial Resistance Patterns Of Salmonella Isolated From Poultry Farms, Carmen G. Velasquez Moreno

Open Access Theses

Antimicrobial agents are used in human medicine to treat infections by inhibiting the growth of bacteria. The same or similar drugs are used in in food-producing animals for therapeutic and sub-therapeutic purposes. Antimicrobial resistant bacteria that develop on farms are a public health risk as these organisms may contribute to treatment failures in infected humans. The main objective of this study was to determine the prevalence of Salmonella isolated from poultry farms in two different seasons to evaluate the effect of recommended biosecurity practices. Specifically, we identified Salmonella serotypes, measured antimicrobial resistance (AMR), and characterized AMR patterns. We hypothesized that …

A Comparison Of The Efficacy Of Radiant And Immersion Frying Using Hash Brown Patties As A Model Food Matrix, Kaitlin R. Kaczay

Open Access Theses

Radiant frying is an alternative technique to traditional immersion frying. While enjoyed by consumers, immersion fried foods are typically high in fat. Radiant frying uses infrared energy to produce finished products with similar sensory characteristics to traditional frying, but with significantly less fat. This research compared the efficacy of radiant and immersion frying using hash brown patties as a model food matrix by measuring temperature profiles, heat flux profiles, moisture and oil contents, peak shear force, color, mottling, and crust thickness as well as executing semi-trained and untrained sensory evaluations. The FryLess 100K Radiant Fryer was used for all experimentation. …

Evaluation Of Thermal Process Lethality In Meat For Non-Pathogenic Escherichia Coli As A Surrogate For Salmonella, Morgan Alyse Redemann

Open Access Theses

Non-typhoidal Salmonella is the leading cause of foodborne illness in the United States, resulting in about 20,000 hospitalizations and nearly 380 deaths annually. The meat processing industry has been especially plagued by Salmonella, from meat-inherent sources and more alarmingly, cross-contamination. For ready-to-eat (RTE) meat products specifically, this can cause significant problems in processing facilities ensuring safe product for consumption, resulting in foodborne illness.

The development of standard lethality compliance guidelines by the United States Department of Agriculture Food Safety and Inspection Service (USDA-FSIS) within Appendix A assists processors in confirming that Salmonella is inactivated in RTE beef and poultry products, …

Genomic And Transcriptomic Analysis Of Biofilm Formation In Persistent And Transient L. Monocytogenes, Clara Assisi

Open Access Theses

The Next Generation Sequencing (NGS) has been popularized and aid in the advancement of many fields of science. The other field of science that is being revolutionized is food science and technology, especially food safety. NGS application in food safety, especially the whole genome sequencing analysis (WGS), has been widely used for tracing back the source of outbreaks. The other application of NGS that is also being developed is the analysis of global transcriptomic or RNA-sequencing (RNA-Seq). In this research, we utilize NGS (Ilumina MiSeq Sequencing platform) to perform sequence comparison and identify single nucleotide polymorphisms (SNPs) and observe the …

Antibacterial Activity Of Essential Oil Encapsulated Sodium Iota-Carrageenan Fibers, Carlos D. Carter

Open Access Theses

Spoilage microorganisms cause food waste and loss of quality. While the foodborne pathogen outbreaks lead to thousands of hospitalizations and deaths. Essential oils (EOs), plant extracts, possess the required antimicrobial activities and thus their usage stands out as a feasible approach for controlling the undesirable bacterial growth in food systems. However, EOs are highly volatile and lose their activity upon exposure to environmental conditions. In this regard, their encapsulation in Generally Recognized As Safe (GRAS) matrices such as food grade polysaccharides especially iota-carrageenan could be one of the viable alternatives. Iota-carrageenan, sulfated polysaccharide from marine algae, is being used in …

Impact Of Microwave-Assisted Heating And Enzymatic Treatment On Functional And Antioxidant Properties Of Rainbow Trout (Oncorhynchus Mykiss) By-Product Hydrolysates, Elizabeth Bich Hang Nguyen

Open Access Theses

Fish protein hydrolysates (FPH) have been widely used as a mean to better utilize fishery by-products through the use of proteolytic enzymes to produce a wide range of functional peptides that can be used as food ingredients. Studies have shown that these functional peptides have enhanced interface-stabilizing properties (e.g. functionality) and antioxidant activity. FPH production can be accelerated by using rapid heating methods (e.g. microwave) compared to slower conventional heating (CH). The objective of this study was to investigate the effects of microwave heating (MW) during enzymatic hydrolysis on functionality and antioxidant properties of FPH. Treatments consisted of adding Alcalase™ …

Influence Of Dietary Polyphenols On Carbohydrate Intestinal Digestion And Absorption, Sydney E. Moser

Open Access Dissertations

Both epidemiological and clinical evidence support the notion that polyphenol rich foods and beverages may modify glycemic response, glucose homeostasis and subsequent risk of Type-2 diabetes. In vitro evidence typically derived from experiments with pure phenolics and phenolic rich extracts have pointed to this benefit being associated with two potential mechanisms: (1) the ability of specific polyphenolics to inhibit carbohydrate digestion (amylase and glucosidase) and (2) polyphenolic inhibition of intestinal glucose transport. While the high potential of these activities is evident, little is actually known regarding the extent to which these benefits are extendable to the actual food matrix these …

Mitigating Prevalence And Persistence Of L. Monocytogenes Using Novel Sanitation Strategies In Delis, Susan Rose Hammons

Open Access Dissertations

Ready-to-eat (RTE) deli meats sliced at retail are predicted to cause 83% of deli meat-associated listeriosis cases annually. While L. monocytogenes is commonly found in delis (55-90%), environmental prevalence varies by store (0-40%). Study 1 evaluated efficacy of 10 standardized SSOPs by testing 28 food and non-food contact surfaces for L. monocytogenes over 6 months in 30 retail delis. Intervention strategies employed in this study significantly decreased L. monocytogenesprevalence on FCS and NFCS in stores with moderate prevalence (0.5%, 0.8% reduction). However, we found that L. monocytogenes could persist despite implementation of SSOP control strategies. Study 2 assessed an …

The Bone-Protective Effect And Mechanism Of Soluble Corn Fiber, Steven A. Jakeman

Open Access Theses

Postmenopausal women are at greatest risk among healthy individuals of developing osteoporosis and associated fractures. Nondigestible, fermentable dietary carbohydrates have been shown to improve calcium absorption in adolescents and bone-strength parameters in the rat model. Of particular interest is soluble corn fiber (SCF), which improved rat bone strength the most in a survey of novel fibers, and improved calcium absorption by up to 13% in teen girls. Hypotheses about the mechanism behind this effect revolve around the production of short-chain fatty acids (SCFAs) in the large intestine during fermentation. The purpose of this work was to determine if SCF would …

Influence And Characterization Of Microbial Contaminants Associated With The Fda Bam Method Used To Detect Listeria Monocytogenes From Romaine Lettuce, Christopher E. Bach

Open Access Theses

Over the past few decades in the US, fresh produce commodities have become increasingly prevalent vehicles for the attribution of foodborne illness. Recent outbreaks of the bacterial foodborne pathogen Listeria monocytogenes linked to fresh produce highlight this immediate issue facing food safety. The most widely used method to screen L. monocytogenes from food matrices in the US is the Bacteriological Analytical Manual (BAM) developed by the Food and Drug Administration (FDA). Detection of this pathogen from all foods is primarily accomplished by using four FDA approved Listeria selective media: Oxford (OXA), modified Oxford (MOX), Lithium chloride-phenylethanol-moxalactam fortified with esculin and …

Persistence And Internalization Of Listeria Monocytogenes In Romaine Lettuce, Lactuca Sativa Var. Longifolia, Archana G. Shenoy

Open Access Theses

Listeria monocytogenes, has been implicated in a number of outbreaks involving fresh produce. While no L. monocytogenes outbreaks have been linked to romaine lettuce, the number of lettuce recalls specific to L. monocytogenes is increasing. Understanding the potential of persistence and internalization of L. monocytogenes on and within romaine lettuce will aid in determining food safety risk. Persistence of three L. monocytogenes strains on three romaine lettuce cultivars was assessed independently by inoculating seeds in 25 ml of 8 log CFU/ml for 30 minutes. Seeds were grown on two soil types (i.e. standard potting mix, Indiana top soil) or sterile …

Effect Of Salts On The Structure-Function Relationships Of Sodium Kappa-Carrageenan, Lohit Myneedu

Open Access Theses

Carrageenans are sulfated marine polysaccharides used in a wide variety of food applications such as bodying, gelling, thickening and emulsion stabilization in water- and milk-based systems. They also find promising pharmaceutical usage due to antiinflammatory, anti-tumor and anti-coagulant activities, to name a few. Among them, kappa-carrageenan is favored owing to its desirable properties such as high gel strength and stability. Though the significance of cations on the structure-function relationships is well-documented, the role of anions is still elusive. This investigation aims at providing the pertinent details, especially in the presence of halide ions such as Cl-, Br- and I-. In …

Transcriptional Stress Response In Foodborne Pathogens, Aaron M. Pleitner

Open Access Dissertations

Novel molecular method use is leading to better identification and understanding of microbial presence in food and food processing environments. The application of molecular methods targeting foodborne pathogens provides genetic profiling and targeted intervention methods. Whole-genome sequencing (WGS) provides information on the genomic uniqueness of specific pathogens and is being implemented in epidemiological investigations. Transcriptomic profiling allows for tracking the differential expression of genes and elucidating stress responses. Effective methods and treatments require an understanding of intervention (e.g. sanitizers) and treatment (e.g. antibiotics) mechanisms and efficacies. Accurate novel molecular method use requires proper learning of theory and data management. ^ …

Dietary Carbohydrates Influence The Structure And Function Of The Intestinal Alpha-Glucosidases, Mohammad Chegeni

Open Access Dissertations

As the primary products of starch digestion by pancreatic α-amylase, maltooligosaccharides (including maltose) are the main substrates for the α-glucosidases at the intestinal brush border. Here, maltose was shown to induce the formation of a higher molecular weight (HMW) sucrase-isomaltase (SI) species in Caco-2 cells that sorts more quickly to the enterocyte surface to act as a digestive enzyme. As this finding suggested a maltose sensing ability of small intestinal enterocytes, molecular mechanisms associated with the maturation and trafficking of HMW SI were further investigated. A pulse-chase experiment using [ ³⁵S]-methionine revealed a higher rate of early trafficking and …

Quality And Safety Attributes Of Sun-Dried Raisins From Afghanistan, Stacy A. Mccoy

Open Access Theses

Raisins are an important export commodity for Afghanistan, however, Afghan packers are challenged to export to markets seeking high quality products due to limited knowledge regarding their quality and safety. To evaluate this, Afghan raisin samples from pre-, semi-, and post-processed raisins were obtained from a raisin packer in Kabul, Afghanistan. The raisins were analyzed and compared to U.S. standards for processed raisins. The samples tested did not meet U.S. import standards for embedded sand, but the process used to clean the raisins is suitable to maintain food safety standards.

Previous Afghan raisin shipments have been rejected from the U.S. …

Invasive Silver Carp (Hypophthalmichthys Moltrix) Protein Hydrolysates And Their Efficacy In Increasing Seedling Vigor And Reducing Seed Borne Pathogen Growth, Shanleigh Pauline Thomson

Open Access Theses

Silver carp are an invasive fish species introduced into the United States within the last forty years. Unable to be effectively eradicated or commercialized as a source of food, other methods must be developed to control and/or use these fish. Fish protein hydrolysates (FPH) are products derived from the proteins inherent within fish. Development of FPH from Silver carp for a variety of uses could aid in controlling their expanding population and provide organic produces with a seed treatment option which is not available to them currently.

In the first study, FPH were used as a seed vigor treatment for …

African Starchy Foods, Gastric Emptying, And Starch Digestion In Malian Stunted Children, Fatimata Cisse

Open Access Dissertations

Starch serves as the main energy source in cereal and tuber-rich diets, and its glycemic response profile has been associated with health-related conditions. Sorghum and millet are known to have relatively low starch digestibility, a potentially desirable property for controlling blood glucose response and providing sustained energy. Gastric emptying rates of traditional sorghum and millet-based African foods of the Sahelian region (couscous, thick and thin porridges made from millet and/or sorghum) were compared to those of non-traditional "modern" foods that are mostly consumed in urban areas using a non-invasive 13C-labelled octanoic acid breath test in healthy volunteers. The obtained results …

Differences In Carbon Dioxide Evolution From Samples Of Shelled Corn Subjected To Various Storage Treatments, Cininta Alp Pertiwi

Open Access Theses

Shelled corn was collected from two sources - commercial grain elevators and corn harvested from Purdue University farms and then frozen until tested. Using a carbon dioxide (CO₂) test kit manufactured by Woods End Laboratories, CO₂ evolution measurements were conducted on shelled corn from both sources, after the samples were re-wetted to approximately 21% moisture content, placed in a 473 ml glass jar, and incubated at room temperature for 72 hours. The CO₂ test kit uses a gel that changes color in response to a change in the level of CO₂ in the surrounding air. …

Role Of Resveratrol Metabolites In Adipose Function, Mikaela Lynn Allan

Open Access Theses

The rise in obesity rate has drastically increased over the last few decades and has quickly grown into a worldwide epidemic. Large increases in visceral adipose tissue accumulation increase risk for metabolic disorders including insulin resistance, type 2 diabetes, and cardiovascular diseases. Currently, increased levels of circulating non-esterified fatty acids (NEFA) have been suggested to be the mediator linking obesity and type 2 diabetes. Studies identifying ways to alleviate mobilization of NEFA in adipose tissue via dietary phytochemicals may useful as a therapeutic approach. Despite the established benefits of resveratrol in health and in the development of obesity, the role …

Characterization Of Water-Solid Interactions In Crystalline Ingredients And Development Of Deliquescence Measurement Recommendations, Matthew C. Allan

Open Access Theses

There are five major mechanisms of water-solid interactions. The primary focus of this thesis was on two of these: deliquescence and hydrate formation. Many crystalline food ingredients are deliquescent compounds (e.g., NaCl, sucrose, and ascorbic acid) and some are both deliquescent and hydrate formers (e.g., glucose, thiamine HCl, citric acid). Deliquescence is the first order phase transformation of a crystalline solid to a solution above a critical relative humidity (RH) known as the deliquescence point (RH0). A crystalline hydrate is a pseudo-polymorph in which water is incorporated into the crystal structure, altering the molecular formula and the physical properties.^ To …

Evolution Of Food Quality Demand In The Food Service Industry In China: The Case Of Duck, Rachel Alison Carnegie

Open Access Theses

Booming economic growth and rising consumer incomes have impacted food preferences and purchasing behavior in China. At the same time, several internationally publicized food safety incidents, particularly in the animal husbandry sector, have heightened awareness of and concern for food safety and quality in meat and dairy. Rising quality demand and safety concerns have been studied at length in the food retail sector, but also appear to be important in the food service industry. This research uses data from a survey of duck restaurant managers and consumers in Beijing, Shanghai, Chengdu, and Guangzhou to determine preferences and willingness to pay …

High Voltage Atmospheric Cold Plasma Treatment Of Refrigerated Chicken Eggs For Control Of Salmonella Enteritidis On External Surfaces, Yi Chen

Open Access Theses

The global market for eggs is projected to reach 1.154 trillion by the year 2015. The number one risk to consumers from chicken eggs is contamination with Salmonella Enteritidis (SE). FDA estimates each year 142,000 illnesses in the U.S. are caused by SE contamination in chicken eggs. The first objective of this research study was to evaluate a novel High Voltage Atmospheric Cold Plasma (HVACP) technology in reducing externally inoculated SE on refrigerated chicken eggs. Raw, chicken eggs attached with SE population (10 7 CFU/ml), were placed in plastic containers filled with either dry Air (22%O2 , 78%N2 ) or …

Physical And Chemical Attributes Of A Genetically Modified Fruit Pectin, Carl Patrick Littrell

Open Access Theses

Pectin is an important polymer used in the food industry as a thickening and gelling agent. Though pectin is ubiquitous in plants, chemical and structural differences among pectin molecules prevent most from being viable for industrial use. Enzymes found naturally in fruit cell walls during the ripening process impair many desirable attributes of fruit pectins, rendering them unsuitable for industrial applications. Pectin methylesterase (PME) is one such enzyme whose expression can be altered during ripening through the use of recombinant genetic engineering. Reduction in levels of PME results in increased degree of methylation and molecular size of pectin, greatly increasing …

Fact Or Fiction: Random Mating In Field Populations Of Western Corn Rootworm (Diabrotica Virgifera Virgifera Leconte) Emerging On Bt And Refuge Corn Plants, Steven Joel Smith

Open Access Theses

The western corn rootworm, or WCR, (Diabrotica virgifera virgifera LeConte) is the most significant pest of field corn (Zea mays) in the United States, and has recently expanded its range into Europe. Since 2004, hybrid corn containing Bt toxins targeting the corn rootworm complex have been heavily adopted and are now the primary control measure for this pest in North American corn production. ^ The evolution of resistance is an ongoing concern, and to ensure Bt products will retain their usefulness, insect resistance management (IRM) tactics using various refuge structures have been adopted. One of the key …

Crystallization Inhibitor Properties Of Polymers And Effects On The Chemical And Physical Stability Of L-Ascorbic Acid During Preparation And Storage, Belinda Christina

Open Access Theses

Crystalline L-ascorbic acid (VitC) is an essential nutrient solid that is widely used in food applications for fortification, antioxidant, and label claim purposes. VitC is known as one of the most unstable vitamins, and its content must be declared on food labels. Interest has been increasing in creating amorphous solid structures for improving the solubility and/or dissolution rates of crystalline compounds. One of the most promising methods studied to prevent the crystallization of an amorphous solid is the use of polymers in dispersions, although the specific polymer properties that lead to the best physical stability for a particular type of …

Quality Changes In Hermetically Stored Corn Caused By Fungi And Sitophilus Zeamais, Nda-Agyima Addae-Mensah K

Open Access Theses

Hermetic storage has been shown to be effective in controlling insect pests and maintaining grain quality of dry grains at 13% moisture and below. However, the feasibility and use of hermetic storage for grains at intermediate mid-moisture levels under the influence of the sub-Saharan African weather conditions is relatively unknown. Hermetic storage experiments were conducted on grade 1 "6297 and 6333 VT RIB" hybrid corn under controlled temperature conditions at 10 degrees centigrade and 25 degrees centigrade at target approximate moisture content levels of 11, 15, 18 and 21% wet basis for a total storage period of 6 months. Corn …

Shrinkage Prediction During Pasta Dehydration, Gina Michelle Bressani

Open Access Theses

Shrinkage models from different fields of study were reviewed. Pasta was used as a model to further develop the hypothesis of predicting shrinkage in terms of the rate of relaxation and the rate of moisture loss. An extended literature review of pasta properties, such as isotherms, diffusivity, glass transition, rheological properties, and shrinkage was conducted. Isotherm and glass transition models were developed from the literature data acquired. Creep was tested with a 25 mm-diameter flat plate at 20 to 40°C at varying moisture content. Viscoelastic properties for the Burgers model for creep were determined, where higher moisture content samples resulted …

Fatty Acids And Mercury In Seventy Seven Species Of Commercially Available Finfish In The United States, Dennis P. Cladis

Open Access Theses

Finfish are consumed across the United States and constitute an important part of the American diet. However, seafood consumption can be a tenuous topic, with supporters highlighting the health benefits of eicosapentaenoic acid (EPA, C20:5n3) and docosahexaenoic acid (DHA, C22:6n3) and opponents emphasizing the neurotoxicity of methylmercury. Because all fish contain varying amounts of EPA, DHA, and methylmercury, the need for clear and unbiased information is essential to alleviate the confusion experienced by many consumers and empower them to make informed decisions regarding seafood consumption. As the market changes and more fish originate from aquaculture sources, where diets are controlled, …