Food Microbiology Commons^™

Microbiota Metabolic Product Deoxycholic Acid Prevents Campylobacter Jejuni Chicken Colonization Through Modulating Ceca Anaerobes, Bilal Ali Alrubaye

Theses and Dissertations

Campylobacter jejuni is a prevalent infectious enteritis mainly foodborne from chickens. Despite of reducing C. jejuni food contamination dramatically decreases campylobacteriosis, few effective approaches are available for the bacterial reduction in chickens. The aim of this study was to use microbial metabolic product deoxycholic acid (DCA) to reduce C. jejuni chicken colonization. Broiler chicks were fed 0 or 1.5 g/kg DCA, lithocholic acid (LCA), or urodeoxycholic acid (UDCA) in diets or orally gavaged with cholic acid (CA, 1.5g/kg body weight). Birds were also transplanted with DCA modulated anaerobes (DCA-Anearo) or aerobes (DCA-Aero). Birds were infected with ...

Aqueous Ozone Inactivation Of Viruses And Bacteria On Biotic And Abiotic Surfaces, Cailin Dawley

Theses and Dissertations

Produce is susceptible to contamination by foodborne pathogens. Food service establishments utilize sanitizing agents to reduce microbes on produce surfaces. The research objectives were to evaluate the efficacy of aqueous ozone 1) on the inactivation of viruses and bacteria on produce; 2) on the inactivation of viruses on stainless steel; and 3) against viruses in association with bacteria on produce surfaces. For objective 1, Boston bibb lettuce and cherry tomatoes were spot inoculated with a cocktail of viruses (murine norovirus (MNV) and MS2 bacteriophage) or bacteria (Enterobacter cloacae and Bacillus cereus) and washed for 40 min with samples taken every ...

Efficacy Of Antimicrobial Mitigation On Escherichia Coli Cfu And Growth And Development Of Hydroponic Leafy Greens, Nathan J. Eylands

Theses and Dissertations

The Food and Drug Administration (FDA) have set new standards that apply to agriculturalists producing crops eaten fresh and/or raw by consumers. This new produce safety rule, known as the Food Safety Modernization Act (FSMA), has established science-based standards for all areas of production in agriculture with regards to microbial contamination. Escherichia coli (E. coli) O157:H7 is a particular bacterium of concern under FSMA guidelines. Grower compliance is mandatory and therefore vital to the continuation of any farm. Greenhouse hydroponic growers have shown advantages in efficiency when compared to conventional farming methodology. Those, however, with recirculating hydroponic systems ...

Assessment Of Salmonella Enterica Biofilms And Expression Differences Among Serovars, Zhaohao Shi

Theses and Dissertations

Biofilms are communities of microorganisms associated by a matrix of extracellular polymers. In this state, microorganisms occupy an ecological niche distinct from their free-floating, planktonic counterparts. Also, biofilm bacteria become biologically unique as they form communities and lose motility. The acquisition of these physiological attributes enables the biofilm to persist through harsh environmental conditions, including antimicrobial induced stress and to resist sanitization efforts. Because of these features, biofilms can rapidly disseminate across numerous surfaces and as they establish, become challenging to remove. This is a particular issue for the food industry as processing plants offer favorable conditions for biofilm formation ...

Bacterial Abundance And Resistance In Ground Beef Varieties, Savannah Kumar, Sarah M. Boomer

PURE Insights

Raw ground beef purchased at supermarkets across America have one thing in common: they harbor bacteria, some of which are drug resistant and can be detrimental to public health. To understand the impact of farming and processing practices on the quantity of bacteria and drug resistance, organic and regular beef were assessed using MacConkey media. Bacterial colonies were sorted according to lactose utilization, with positive colonies representing fecal E. coli. Lactose negative colonies were further characterized into one of two groups (fecal Hafnia-like or soil Pseudomonas) using a variety of metabolic tests (oxidase, sulfur, indole). Advanced metabolic testing showed that ...

A Risk-Based Approach To Evaluate The Impact Of Interventions At Reducing The Risk Of Foodborne Illness Associated With Wheat-Based Products, Luis Sabillon

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

Pathogens are emerging on previously unrecognized food vehicles, such as wheat flour, which is a widely consumed commodity. Despite its low water activity, wheat-based ingredients and products have been implicated in several foodborne outbreaks over the last few years, resulting not only in the recall of food products but also in consumer illnesses. As a raw agricultural commodity, wheat is exposed to naturally occurring microbiological contamination that may compromise the overall safety of flour and other derived products. To address the increased concern regarding the safety of wheat-based foods, the objectives of the present research study were designed to develop ...

Experimental Evaluation Of The Importance Of Colonization History In Early-Life Gut Microbiota Assembly, Inés Martínez, Maria X. Maldonado-Gomez, João Carlos Gomes-Neto, Hatem Kittana, Hua Ding, Robert J. Schmaltz, Payal Joglekar, Roberto Jiménez Cardona, Nathan L Marsteller, Steven W. Kembel, Andrew K. Benson, Daniel A. Peterson, Amanda Ramer-Tait, Jens C. Walther

Faculty Publications in Food Science and Technology

The factors that govern assembly of the gut microbiota are insufficiently understood. Here, we test the hypothesis that inter-individual microbiota variation can arise solely from differences in the order and timing by which the gut is colonized early in life. Experiments in which mice were inoculated in sequence either with two complex seed communities or a cocktail of four bacterial strains and a seed community revealed that colonization order influenced both the outcome of community assembly and the ecological success of individual colonizers. Historical contingency and priority effects also occurred in Rag1^-/- mice, suggesting that the adaptive immune system is ...

Lack Of Evidence For Erm(B) Infiltration Into Erythromycin-Resistant Campylobacter Coli And Campylobacter Jejuni From Commercial Turkey Production In Eastern North Carolina: A Major Turkey-Growing Region In The United States, Hannah K. Bolinger, Qijing Zhang, William G. Miller, Sophia Kathariou

Veterinary Microbiology and Preventive Medicine Publications

In Campylobacter spp., resistance to erythromycin and other macrolides has typically implicated ribosomal mutations, especially substitutions in the 23S rRNA genes. However, in 2014, the macrolide resistance gene erm(B) was reported for the first time in Campylobacter and shown to be harbored by a multidrug resistance island in the chromosome of the swine-derived strain Campylobacter coli ZC113. erm(B)-positive C. coli and Campylobacter jejuni strains from the food supply have been mostly reported from China. However, erm(B)-positive C. coli isolates were also detected recently in fecal samples from turkeys in Spain. To determine whether erm(B ...

Reporter Bacteriophage T7nlc Utilizes A Novel Nanoluc::Cbm Fusion For The Ultrasensitive Detection Of Escherichia Coli In Water., T.C. Hinkley, S. Garing, S. Singh, A-L. M. Le Ny, K.P. Nichols, J.E. Peters, Joey N. Talbert, S.R. Nugen

Food Science and Human Nutrition Publications

Rapid detection of bacteria responsible for foodborne diseases is a growing necessity for public health. Reporter bacteriophages (phages) are robust biorecognition elements uniquely suited for the rapid and sensitive detection of bacterial species. The advantages of phages include their host specificity, ability to distinguish viable and non-viable cells, low cost, and ease of genetic engineering. Upon infection with reporter phages, target bacteria express reporter enzymes encoded within the phage genome. In this study, the T7 coliphage was genetically engineered to express the newly developed luceriferase, NanoLuc (NLuc), as an indicator of bacterial contamination. While several genetic approaches were employed to ...

Thermal Inactivation Kinetics Of Salmonella Enterica And Enterococcus Faecium In Ground Black Pepper, Sabrina Vasquez

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

Food safety concerns of low-a_wfoods have boosted, given the increased number of foodborne illnesses related to these products. Black pepper, among other spices, has been implicated in several outbreaks and recalls in recent years.Salmonella entericahas been identified as the causing agent of outbreaks of contaminated spices. Therefore, increased efforts should be conducted to ensure food safety of spices, including black pepper. Food Safety Modernization Act (FSMA) demands all food processing facilities to conduct proper validations of the decontamination technologies applied to food products. Complete thermal process validations require a deep understanding of the thermal inactivation kinetics ...

Effect Of Grain Sorghum Polyphenols On Fecal Fermentation, Danielle Marie Ashley

Theses and Dissertations

Obesity is an increasing epidemic which during 2015-2016 afflicted 39.8% of adults and 18.5% of youth in the United States. Not only can obesity affect quality of life, but it can lead to life-threatening diseases such as type 2 diabetes, heart disease, stroke, and some cancers. Animal and human research have demonstrated a pattern of gut microbiota perturbation in overweight and obesity, characterized by a reduction of beneficial bacterial species and increase in harmful species. Diet has been established as a contributing factor in gut ecology, and foods including fiber, resistant starch, and polyphenols have been found to ...

Implementation Of Iso/Iec Practices In Small And Academic Laboratories, Eric Layne Oliver

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

Food Manufacturers are facing challenging times due to regulations such as the Food Safety Modernization Act (FSMA) requiring them to provide evidence they are producing safe foods. Food testing laboratories aid in the mitigation of food safety issues providing evidence that a manufacturers food safety system is acceptable. To perform these activities laboratories are required to adhere to certain standards such as ISO/IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories. However, implementation of ISO/IEC 17025 practices is challenging, especially for small and academic laboratories, due to lack of available guidance. A long-term goal of ...

Investigating The Potential Of Plant-Derived Antimicrobials For Controlling Campylobacter Jejuni In Poultry And Poultry Products, Basanta Raj Wagle

Theses and Dissertations

Campylobacter jejuni infection in humans is strongly associated with the handling and consumption of contaminated poultry products. Interventions reducing C. jejuni contamination in poultry would reduce the risk of subsequent human infections. In the first study, the efficacy of a Generally Recognized as Safe (GRAS) compound, eugenol (EG; derived from cloves), as an antimicrobial dip treatment to reduce C. jejuni in postharvest poultry was evaluated. The antimicrobial efficacy of EG was studied in suspension, emulsion and nanoemulsion delivery systems. EG suspension reduced C. jejuni counts with the greatest reduction of >2.0 Log CFU/sample for the 2% dose of ...

Methane Emissions From Rice Production On A Silt-Loam Soil In Arkansas, Joshua Jeffry Humphreys

Theses and Dissertations

Methane (CH4) emissions from rice (Oryza sativa L.) production are a source of concern in the environmental and agricultural communities. New and/or revised agronomic methodologies will be needed to identify production practice combinations that reduce CH4 emissions without decreasing yields. The objective of this multi-year study was to evaluate the effects of water management (i.e., full-season flood and mid-season drain) (2015), cultivar (i.e., pure-line cultivar ‘LaKast’ and the RiceTec hybrid “XP753”) (2015), soil organic matter (SOM) concentration (2016), and tillage [conventional tillage (CT) and no-tillage (NT)] and urea-based fertilizers [N-(n-butyl) thiophosphoric triamide (NBPT)-coated urea and ...

Inefficient Metabolism Of The Human Milk Oligosaccharides Lacto-N-Tetraose And Lacto-N-Neotetraose Shifts Bifidobacterium Longum Subsp. Infantis Physiology, Ezgi Ozcan, David Sela

Open Access Articles

Human milk contains a high concentration of indigestible oligosaccharides, which likely mediated the coevolution of the nursing infant with its gut microbiome. Specifically, Bifidobacterium longum subsp. infantis (B. infantis) often colonizes the infant gut and utilizes these human milk oligosaccharides (HMOs) to enrich their abundance. In this study, the physiology and mechanisms underlying B. infantis utilization of two HMO isomers lacto-N-tetraose (LNT) and lacto-N-neotetraose (LNnT) was investigated in addition to their carbohydrate constituents. Both LNT and LNnT utilization induced a significant shift in the ratio of secreted acetate to lactate (1.7-2.0) in contrast to the catabolism of their ...

Effect Of Gallic And Ferulic Acids On Oxidative Phosphorylation On Candida Albicans (A72 And Sc5314) During The Yeast-To-Hyphae Transition, Rehab Aldahash

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

Candida albicans is a dormant commensal in the mucosa of healthy individuals but can become an opportunistic pathogen when the host microflora is compromised. It has been reported as the most common cause of fungal infection among hospitalized U.S. patients, with elevated mortality rate. Candida species have been reported as resistant to antifungal drugs that increase the application of novel strategies to treat this infection. Among the natural compounds that have most gained attention as potential agents against fungi are phenolic compounds against fungi. C. albicans has the ability to switch phenotype from yeast-to-hyphae cells, with hyphae being the ...

Transcriptomic Analysis Of Salmonella Enterica Newport Adaptive Response To Oxidative Antimicrobials, Dara Melanie Smith

Masters Theses

Agricultural water systems are a known potential source for contamination of fresh produce with foodborne pathogens including Listeria monocytogenes, pathogenic Escherichia coli, as well as Salmonella enterica strains. To reduce this associated risk, antimicrobials such as hypochlorite compounds and peroxyracetic acid (PAA) have been utilized as in-line irrigation disinfectants and as post-harvest treatments. These treatments are considered effective and commonly used; however, pathogenic microbes like Salmonella have the ability to adapt to many environmental conditions. Adaptive response to environmental factors like oxidative conditions, contributes to transfer, attachment, and resilience of Salmonella on surfaces. Through RNA sequencing and analysis of the ...

Breeding For Resistance In California Strawberry To Verticillium Dahliae, Zachary Christman

Theses, Dissertations, and Student Research in Agronomy and Horticulture

Since 1930 the University of California, Davis, has been developing strawberry cultivars that are adapted to the agricultural industry and regional farms. Developing cultivars that require fewer inputs are of significant economic importance in agronomy. Developing a crop resistant to a disease is beneficial for horticulturists since less labor and chemicals are needed for a high yield.⁶

In commercial strawberry cultivars, complete resistance to V. dahlia is extremely rare. The majority of Californian strawberry cultivars are highly susceptible to it.² Over the last 18 years of plant breeding for strawberry cultivars with a high degree of resistance and ...

Caenorhabditis Elegans Model To Study Antimicrobial Treatment On E. Coli O157:H7, Parita Patel

Masters Theses

An increase in antimicrobial resistance bacteria has endangered our ability to treat infectious diseases. Lack of good in-vivo model has made it difficult to study antimicrobial resistance. In this study, we have used an inexpensive and short life span in-vivo model namely, Caenorhabditis elegans (C. elegans) to study antimicrobial treatment using pathogenic Escherichia coli O157:H7, a multidrug resistance bacterium that causes life threatening infection in humans.

We have investigated the influence of live vs. heat killed non-pathogenic E. coli OP50 (OP50) as a food source on the growth and survival of infected C. elegans mutant AU37 with E. coli ...

Development Of Methodology For Rapid Bacterial Detection In Complex Matrices Using Sers, Madeline Tucker

Masters Theses

Fresh foods, including meats and produce are the fastest growing market in the supermarket and the class of foods most likely to cause a bacterial foodborne illness. As the rate of consumption of perishable products increases, rapid detection of pathogens within the food supply becomes a critical issue. Current methods used for the detection of bacteria that cause food-borne illnesses are time consuming, expensive and often require selective enrichment. In this study we adapted a separation technique originally developed for PCR to extract bacteria from ground beef using β-cyclodextrin (β-CD) and milk protein coated activated carbon (MP-CAC) as filtration agents ...