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Assessment Of Salmonella Enterica Biofilms And Expression Differences Among Serovars, Zhaohao Shi Dec 2018

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 ...


Use Of Alamarblue As An Indicator Of Microbial Growth In Turbid Solutions For Antimicrobial Evaluation, Precious Henshaw Oct 2018

Use Of Alamarblue As An Indicator Of Microbial Growth In Turbid Solutions For Antimicrobial Evaluation, Precious Henshaw

Masters Theses

The use of antibiotics in animal feed is a large cause of concern due to bacterial resistance, which occurs when bacteria change after exposure to antibiotics and become less affected by the drug. Consequently, the desire to find a replacement for these antibiotics has garnered interest in both farmers and consumers. The ideal substance would display antimicrobial activity without promoting bacterial resistance and would still function as a growth promoter in animals. One antimicrobial that fits this criterion is carvacrol, a compound found in oregano extract. Carvacrol exhibits antimicrobial activity in a number of bacteria, including E.coli O157:H7 ...


Study Of Rheological, Chemical, And Microbiological Properties Of Chami, A Traditional Emirati Soft Chees, Aysha Othman Abdullah Al Katheeri Apr 2018

Study Of Rheological, Chemical, And Microbiological Properties Of Chami, A Traditional Emirati Soft Chees, Aysha Othman Abdullah Al Katheeri

Theses

In this work, ten Emirati Chami cheese samples were collected and analyzed to determine their chemical composition, texture, rheology, and microbiological properties. Chami cheeses showed large variations in moisture (60.9–84.1%), protein (7.5–14.6%), fat (0.5–7.8%), and ash (3.4–8.0%) contents as well as in pH (3.6–4.4), and water activity (0.977–0.999%). The variation in fat content of samples suggested that extra fat was added; this added fat was either butter or vegetable oil as indicated by the fatty acid composition. The different samples showed peaks ...


Four Legs Good, Two Legs Bad: How Slaughterhouse Safety Hasn’T Kept Up With The Times, Emily Ziemski Dec 2017

Four Legs Good, Two Legs Bad: How Slaughterhouse Safety Hasn’T Kept Up With The Times, Emily Ziemski

Capstones

From legal loopholes and outdated rules to undetectable infections and understaffing, the United States Department of Agriculture may not be doing all it can to make sure the American public’s health isn't at risk. As the people of the United States consume over 500 million pounds of beef a year, food safety policy and slaughterhouses are falling behind in proper procedural measurements in the beef industry.

emziemski.com/capstone


Role Of Incompatibility Group 1 (Inci1) Plasmid-Encoded Factors On Salmonella Enterica Antimicrobial Resistance And Virulence, Pravin Raghunath Kaldhone Dec 2017

Role Of Incompatibility Group 1 (Inci1) Plasmid-Encoded Factors On Salmonella Enterica Antimicrobial Resistance And Virulence, Pravin Raghunath Kaldhone

Theses and Dissertations

Foodborne illnesses are a leading cause of infectious diseases in the world. Among enteric organisms Salmonella is a key pathogen. It’s high prevalence in poultry and other food-animal sources make it imperative to study. Salmonella has the ability to modify its genetic content with help of mobile genetic elements such as plasmids. Incompatibiltiy group 1 (IncI1) plasmids are commonly reported in Salmonella. This study evaluates role on IncI1 plasmids in antimicrobial resistance and virulence in Salmonella. Genetic determinants of resistance and virulence are noted among our IncI1-containing Salmonella isolates. These genetic elements are also transferable and reported to carry ...


Experimental Approaches To Understand And Control Salmonella Infection In Poultry, Yichao Yang Dec 2017

Experimental Approaches To Understand And Control Salmonella Infection In Poultry, Yichao Yang

Theses and Dissertations

Salmonella is a major foodborne pathogen around the world and chickens are the major reservoir to transmit Salmonella into the human food chain. For decreasing the infection of Salmonella, we developed six attenuated live vaccines based on Salmonella Enteritidis (SE) and Typhimurium (ST) for testing the cross-serovar and cross-serogroup protection from the challenge of Salmonella Heidelberg and Campylobacter jejuni. One of the constructed vaccine strain showed ability to protect against challenge from Salmonella Heidelberg. Even though some preventive approaches are able to decrease Salmonella colonization in the gastrointestinal tract of chickens or other farm animals, Salmonella transmission mechanisms remain unclear ...


A Transcriptomic Analysis Of Salmonella Enterica Newport In Planta And After Postharvest Sanitization, Laurel Lynn Dunn Aug 2017

A Transcriptomic Analysis Of Salmonella Enterica Newport In Planta And After Postharvest Sanitization, Laurel Lynn Dunn

Doctoral Dissertations

The consumption of fresh produce is increasingly linked to incidence of foodborne illness. Pathogens including Salmonella enterica, Shiga toxigenic Escherichia coli, and Listeria monocytogenes are exposed to produce crops through direct human or animal contact, contaminated agricultural water, bioaerosols, run-off, and improperly treated compost. S. enterica has demonstrated exceptional tolerance to the stresses encountered in the environment, on plant tissue, and from postharvest antimicrobial mitigation strategies. Understanding the transcriptomic mechanisms S. enterica employs to survive these hazards is integral for the development of more effective preventive controls and post-harvest steps to prevent the pathogen from infecting consumers.


Prevalence Of Salmonella Species And Escherichia Coli O157:H7 In Organically Managed Cattle And Food Safety Status Of Selected Meat Products, Joshua Raymond Nazareth Jan 2017

Prevalence Of Salmonella Species And Escherichia Coli O157:H7 In Organically Managed Cattle And Food Safety Status Of Selected Meat Products, Joshua Raymond Nazareth

Graduate Theses and Dissertations

Beef is an important source of food for consumers, thus requiring the safety of beef products important when considering the potential for a foodborne related illness. The food safety status of ground beef and fermented sausage products was examined in the literature along with interventions applied to reduce food safety risk. Ground beef was found to be a more important contributor to foodborne illnesses traced back to beef, and, undercooked ground beef was frequently associated with E.coli O157:H7 outbreaks. Salmonella spp., and E.coli O157:H7 are frequently associated with ground beef. Fermented sausage products were found to ...


The Survival Of Various Pathogenic Organisms In Fats And Oils, Kelsey Ellen Lamb Jan 2017

The Survival Of Various Pathogenic Organisms In Fats And Oils, Kelsey Ellen Lamb

Theses and Dissertations--Animal and Food Sciences

The research within this thesis sought to determine the ability of various animal derived fats and plant derived oils to support the survival of several pathogenic cocktails over a multitude of storage times. The Salmonella study explored the survival rate of a four strain Salmonella cocktail in beef tallow, pig lard, duck fat, coconut oil, and extra virgin olive oil over seven days at 26˚C and 37˚C storage. The animal fats and the coconut oil supported the survival of the bacteria until the conclusion of the study. The Shiga-toxin producing Escherichia coli study explored the survival rate of ...


Prevalence And Antimicrobial Resistance Patterns Of Salmonella Isolated From Poultry Farms, Carmen G. Velasquez Moreno Dec 2016

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 ...


Evaluation Of Thermal Process Lethality In Meat For Non-Pathogenic Escherichia Coli As A Surrogate For Salmonella, Morgan Alyse Redemann Dec 2016

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 ...


A Molecular Approach To Understanding The Effects Of Original-Xpc On The Modulation Of The Cecal Microbiota And The Survival Of Salmonella In The Poultry Host, Stephanie Roto May 2016

A Molecular Approach To Understanding The Effects Of Original-Xpc On The Modulation Of The Cecal Microbiota And The Survival Of Salmonella In The Poultry Host, Stephanie Roto

Theses and Dissertations

Salmonella is a foodborne pathogen commonly associated with poultry products; the economic burden to the U.S. is estimated to be approximately $693 million (without factoring in contaminated eggs). Recently, there has been pressure to withdraw sub-therapeutic levels of antibiotics (also known as antibiotic growth promoters; AGP) from poultry due to concern over antibiotic-resistant bacteria spreading to the human population. Therefore, various feed additives have been researched for their ability in providing protection against harmful pathogens and their potential growth promoting effects, both of which were attributes of poultry treated with AGP. This thesis consists of a comprehensive literature review ...


Effect Of Reduced Sodium Cheese On The Growth Of Pathogenic Bacteria And Inactivation Of Listeria Innocua Using Supercritical Fluid Extraction With Co2, Suyapa Padilla Antunez Apr 2016

Effect Of Reduced Sodium Cheese On The Growth Of Pathogenic Bacteria And Inactivation Of Listeria Innocua Using Supercritical Fluid Extraction With Co2, Suyapa Padilla Antunez

Master's Theses and Project Reports

Listeria monocytogenes continues to challenge the dairy industry in causing post-process contamination of cheeses. To reduce risk of contamination, it is crucial to understand the growth and survival of pathogenic bacteria in cheese products and to develop post-process mitigation strategies. This study evaluated the fate of pathogens in reduced and regular sodium Mozzarella cheese, and the potential of Supercritical Fluid Extraction with CO2 (SFE) to reduce Listeria innocua on Mozzarella and Queso Fresco. The survival of L. monocytogenes, Salmonella, and E.coli O157:H7 (2-3 log CFU/g) in reduced sodium Mozzarella (1.62%), compared to regular sodium Mozzarella ...


Evaluating The Microbial Safety Status Of Products From Sustainable Organic Agriculture, Sai Deepikaa Elumalai Jan 2016

Evaluating The Microbial Safety Status Of Products From Sustainable Organic Agriculture, Sai Deepikaa Elumalai

Graduate Theses and Dissertations

There has been a steady increase in the demand for organic and sustainable agricultural products. Consumers increasingly prefer non – GMO products grown without pesticides and antibiotics. In order to satisfy the increasing demand, several agricultural producers have opted for use of different types of modern agricultural practices which are more efficient and sustainable than conventional methods. My research focuses on two such modern agricultural practices. Because the products from these methods do not have many food safety interventions applied to them, it is important to make sure that they are free of pathogens and are safe for human consumption. My ...


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 ...


Phenotypic And Functional Genomics Analyses Of Salmonella For Food Safety Applications, Turki Dawoud May 2015

Phenotypic And Functional Genomics Analyses Of Salmonella For Food Safety Applications, Turki Dawoud

Theses and Dissertations

Non-typhoidal Salmonella species have been major foodborne zoonotic pathogens causing serious problems in public health and food industry for several decades. Numerous Salmonella species have frequently been associated with different food commodities mainly poultry meat, eggs, and their products. This dissertation begins with a literature reviews discussing many aspects of Salmonella generally; and subsequently focused on two serotypes, Salmonella Enteritidis and S. Typhimurium as they are at the top of all other serovars responsible for most illness cases and outbreaks. In addition, some Salmonella strains have exhibited their ability to tolerate and survive many food processing treatments. We can divide ...


The Effects Of Electrostatic Spraying With Organic Acids In The Disintegration Of Biofilms Formed By E.Coli O157:H7 And Salmonella Typhimurium On Spinach And Cantaloupe, Ahmad Almasoud May 2015

The Effects Of Electrostatic Spraying With Organic Acids In The Disintegration Of Biofilms Formed By E.Coli O157:H7 And Salmonella Typhimurium On Spinach And Cantaloupe, Ahmad Almasoud

Theses and Dissertations

Outbreaks from the consumption of fresh produce are a concern in the United States. The consumptions of fresh produce have increased recently which expose a large segment of society to such outbreaks. Spinach and cantaloupe are minimally heated or processed before consumption which makes them a possible source of foodborne illness. The objective of this research was to investigate the effect of organic acids alone and in combination to reduce attached Salmonella Typhimurium (S.T) and Escherichia coli O157:H7 (E.coli) on spinach and cantaloupe, and to disintegrate biofilm formed by these pathogens by electrostatically spraying with two organic ...


Phenotypic, Physiological And Growth Interactions Among Salmonella Serovars, Juliany Rivera Calo Dec 2013

Phenotypic, Physiological And Growth Interactions Among Salmonella Serovars, Juliany Rivera Calo

Theses and Dissertations

This thesis consists of four research parts: a literature review that covers Salmonella spp., one of the more prominent foodborne pathogens that represents a major risk to humans (chapter 1). Understanding the growth of Salmonella serovars and strains is an important basis for more in depth research. In this case we studied a) the aerobic and anaerobic growth responses of multiple strains from six different serovars, b) how the spent media from different serovars, more importantly S. Heidelberg, affect the growth of S. Typhimurium, and c) determined whether or not two different serovars undergo competitive interactions when they were grown ...


Electrostatic Spray Application Of Food-Grade Organic Acids And Plant Extracts To Decrease Escherichia Coli O157:H7 And Salmonella Typhimurium On Select Produce, Leighanna Maeree Massey Dec 2013

Electrostatic Spray Application Of Food-Grade Organic Acids And Plant Extracts To Decrease Escherichia Coli O157:H7 And Salmonella Typhimurium On Select Produce, Leighanna Maeree Massey

Theses and Dissertations

Both consumers and suppliers have been negatively affected by an increase in foodborne pathogens contaminating fruits. Consequently, there is a need for the development of more efficient antimicrobials and application techniques to decrease contamination. Natural preservatives such as organic acids and plant extracts have demonstrated promising results in decontaminating produce. In addition, the effectiveness of such preservatives may be enhanced by the use of an electrostatic sprayer. The objective of this research was to determine the combinations and concentrations of organic acids and plant extract that were able to reduce Salmonella Typhimurium (ST) and Escherichia coli O157:H7 (EC) inoculated ...


A Comparison Of Salmonella Enterica Serovars: Are Prevalence, Virulence And Responses To Environmental Conditions Serovar Or Strain Dependent?, Nan Zhang Aug 2013

A Comparison Of Salmonella Enterica Serovars: Are Prevalence, Virulence And Responses To Environmental Conditions Serovar Or Strain Dependent?, Nan Zhang

Masters Theses

Salmonella are considered the leading cause of foodborne illnesses with frequent outbreaks in United States. While more than 2500 serovars have been identified, Salmonella Typhimurium and Salmonella Enteritidis are primarily responsible for most human infections while Salmonella Kentucky and Salmonella Heidelburg are currently the most prevalent serovars associated with poultry contamination. The relationship between virulence and prevalence is not fully understood, but may be a result of environmental stress exposure such as acid stress. In this research, organic acid (acetate) and inorganic acid (hydrogen chloride) were applied to 15 different serovars isolated from human infections or poultry. The growth curves ...


Influence Of Compost Particle Size On Pathogen Survival Under Greenhouse Condition, Junshu Diao May 2013

Influence Of Compost Particle Size On Pathogen Survival Under Greenhouse Condition, Junshu Diao

All Theses

The number of foodborne pathogen outbreaks related to fresh produce has increased significantly in recent decades. Animal waste directly applied to agricultural field is one of the possible contamination sources for fresh produce. Composting is one of the recommended means for waste treatments to eliminate or reduce pathogens in manure on farms. Although pathogens can be eliminated by proper composting process, pathogens are able to survive, recolonize and regrow on compost heap surfaces under certain conditions. Due to the outdoor nature of composting process, bioaerosols with different particle sizes can be generated on compost surfaces which can carry pathogens, travel ...


Impact Of Rearing Conditions On The Microbiological Quality Of Retail Poultry Meat, Bridgshe Hardy Dec 2012

Impact Of Rearing Conditions On The Microbiological Quality Of Retail Poultry Meat, Bridgshe Hardy

Masters Theses

Poultry and poultry products are a leading source of foodborne pathogens and illnesses. The rearing conditions of poultry can be an influential factor on the presence of foodborne pathogens including Campylobacter and Salmonella because some types of rearing practices have increased risks in terms of biosecurity. However, there is a gap in knowledge of food safety in raw chicken products and no studies have reported the microbiological quality of turkeys produced under different rearing environments. Thus, the aim of this study was to compare conventionally and organically-reared whole chicken and turkey carcasses purchased from three retail outlets in Knoxville, TN ...


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 ...


Effect Of Crust Freezing On The Quality And Survival Of Escherichia Coli And Salmonella Typhimurium In Raw Poultry Products, Byron Chaves-Elizondo Dec 2010

Effect Of Crust Freezing On The Quality And Survival Of Escherichia Coli And Salmonella Typhimurium In Raw Poultry Products, Byron Chaves-Elizondo

All Theses

Industry has widely used freezing as a strategy to halt pathogen growth and more recently, crust freezing has been suggested as a means to improve mechanical operations, quality, and safety of poultry products. Two separate studies were conducted to evaluate the effect of crust freezing (20 min, -85 ¡C) on the survival of Escherichia coli and Salmonella Typhimurium and on quality and shelf life of raw chicken breasts, with or without skin. For the first study, ampicillin-resistant E. coli JM 109 and nalidixic acid-resistant S. Typhimurium were used in the experiments. A set of cultures was subjected to cold-shock stress ...


Oxidation-Reduction Potential And Growth Of Salmonella Spp And Pseudomonas Fluorescens , James Leslie Oblinger Jan 1972

Oxidation-Reduction Potential And Growth Of Salmonella Spp And Pseudomonas Fluorescens , James Leslie Oblinger

Retrospective Theses and Dissertations

No abstract provided.


Rapid Methods For Determining Staphylococcal Toxins And Salmonellae Associated With Poultry Products , Daniel Yee Chak Fung Jan 1969

Rapid Methods For Determining Staphylococcal Toxins And Salmonellae Associated With Poultry Products , Daniel Yee Chak Fung

Retrospective Theses and Dissertations

No abstract provided.


Microbiological And Functional Changes In Dried Egg Albumen Stored At Elevated Temperatures , George J. Banwart Jan 1955

Microbiological And Functional Changes In Dried Egg Albumen Stored At Elevated Temperatures , George J. Banwart

Retrospective Theses and Dissertations

No abstract provided.