Food Microbiology Commons^™

Biocontrol Of Foodborne Pathogens Using Bacteriophages, Dzhuliya Ignatova, Erion Hogan, Simone Dakare, Jean Lu

Symposium of Student Scholars

Biocontrol of Foodborne Pathogens Using Bacteriophages

Dzhuliya Ignatova, Erion Hogan, Simone Dakare, and Jean Lu

Department of Molecular and Cellular Biology

Abstract

Salmonella and Shigella are two important groups of foodborne bacterial pathogens. Salmonella cause an illness called salmonellosis while Shigella cause shigellosis (bacillary dysentery). The most common symptoms of these illnesses are abdominal cramps, diarrhea, and fever. Shigella can also cause bloody diarrhea. It was estimated that each year Salmonella cause 93.8 million cases of gastroenteritis and 155,000 deaths globally. Shigella causes 164.7 million cases and 1.1 million deaths throughout the world yearly. People get these illnesses mainly by …

Bacteriophages Infecting Enterobacter Cloacae To Reduce Bloater Damage In Fermented Cucumbers

Symposium of Student Scholars

Fermented cucumbers are one of the most important fermented vegetables consumed worldwide. During cucumber fermentations, certain undesirable changes may occur. One of such changes is known as bloater defect (hollow cavities in fermented cucumbers), which is primarily caused by gas-producing bacteria including Enterobacter cloacae. Bloater defect lowers product quality and leads to significant economic loss to the pickle industry, and effective preventative methods are needed. Bacteriophages (phages) are highly host-specific bacterial killers. Use of phages to control unwanted bacteria in foods is a promising approach because phages do not change food properties. This research was to isolate, characterize, and …

Effectiveness Of Bacteriophages Against Bloater-Causing Bacteria Enterobacter Cloacae In A Model Food System, Ashley Reed, Dzhuliya Ignatova, Sandra Kopic, Unique Sardeneta

Symposium of Student Scholars

Effectiveness of bacteriophages against bloater-causing bacteria Enterobacter cloacae in a model food system

Department of Molecular and Cellular Biology

Ashley Reed, Dzhuliya Ignatova, Sandra Kopic, Unique Sardeneta, and Jean Lu

Abstract

Cucumber fermentation is one of the most important vegetable fermentations in the United States and Europe. Enterobacter cloacae and other gas-producing bacteria can cause bloater defect (the gas pockets or hollow cavities formed in fermented cucumbers) which lowers the quality and the yield of fermented cucumbers, thereby resulting in significant economic losses to the pickling industry. Cost-effective strategies to control E. cloacae and other microbiota need to be …

You Are What You Eat — Exploring The Microbiome Through Inquiry-Based Labs. Microbiome Lesson Plans, Karla S. Fuller

Open Educational Resources

If these commonly used spices have the ability to inhibit pathogenic bacterial growth, could they also potentially inhibit the growth of normal, harmless bacteria that live in your body? In this lab, we will test common bacteria for resistance to food additives.

The Persistence Of Human Norovirus Surrogate In Leafy Greens Production System, Wenjun Deng

Graduate Theses and Dissertations

Since mostly consumed raw, foodborne pathogen contamination of leafy greens has led to a large number of foodborne disease outbreaks and illnesses each year in the United States. Human noroviruses (hNoV) are the most common viral pathogen transmitted by leafy greens. In this dissertation, the persistence of the hNoV surrogate Tulane virus (TV) on pre-harvest lettuce and microgreens was investigated. Lettuces are the most studied leafy green model, while previous hNoV research has mainly focused on the post-harvest stage of production. Here, pre-harvest hydroponically grown lettuce were used to determine TV persistence on leafy greens. After inoculation on leaves at …

Process Interventions For Improving The Microbiological Safety Of Low Moisture Food Ingredients, Tushar Verma

Department of Food Science and Technology: Dissertations, Theses, and Student Research

The recurrence of Salmonella in low moisture foods and the implementation of the FSMA rule requires a need to validate legacy and novel processing technologies. In this dissertation, a legacy thermal (extrusion), a novel thermal (radiofrequency (RF) heating), and a non-thermal (chlorine dioxide) technology, were evaluated as intervention technologies for Salmonella in low moisture foods. The twin-screw extruder was performed at different levels of screw speeds, temperatures, moisture contents, and fat contents to understand the impact of processing conditions on Salmonella inactivation in oat flour. At temperature >65°C, the Salmonella population was below the detection limit. At 55°C, Salmonella reduction …

Improving Nutritional Properties And Extractability Of Pea Proteins For Human Consumption Via Fungal Bioprocessing, Camille Massmann

Electronic Theses and Dissertations

Yellow peas are a rich source of protein and phytochemicals. Peas are compatible with many diets restricted by sensitivities, allergies, or personal choice. As a result, peas are gaining popularity in food markets, despite the challenges they present. The biggest challenges for pea proteins in food markets are high content of fiber, starch, and saponins. These components cause processing challenges and create undesirable textures and bitter flavors. Pea proteins are typically extracted with alkaline extraction or air classification methods which result in 80% and 50% protein products respectively. With low protein purity, these products are not competitive with other, more …

An Impedimetric Aptasensing System For The Rapid Detection Of Salmonella Typhimurium, America Sotero

Graduate Theses and Dissertations

Salmonella Typhimurium is a foodborne pathogen associated with raw and undercooked eggs, poultry, beef, fruits, and vegetables. In the United States, Salmonella is responsible for approximately 1.2 million illnesses, 23,000 hospitalizations, and 450 deaths annually. For many years, conventional detection methods such as culture-dependent and PCR-based methods have been the “golden standards” for the detection of this pathogen due to their high sensitivity and reliability. However, they still have some disadvantages such as long enrichment steps and high costs that need to be overcome. The development of a rapid and reliable method for the detection of S. Typhimurium is needed …

Assessment Of Grain Safety In Developing Nations, Jose R. Mendoza

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Grains are the most widely consumed foods worldwide, with maize (Zea mays) being frequently consumed in developing countries where it feeds approximately 900 million people under the poverty line of 2 USD per day. While grain handling practices are acceptable in most developed nations, many developing nations still face challenges such as inadequate field management, drying, and storage. Faulty grain handling along with unavoidably humid climates result in recurrent fungal growth and spoilage, which compromises both the end-quality and safety of the harvest. This becomes particularly problematic where there is little awareness about health risks associated with poor …

Research Tools And Their Uses For Determining The Thermal Inactivation Kinetics Of Salmonella In Low-Moisture Foods, Soon Kiat Lau

Department of Food Science and Technology: Dissertations, Theses, and Student Research

The reputation of low-moisture foods as safe foods has been crumbling over the past decade due to repeated involvement in foodborne illness outbreaks. Although various pasteurization technologies exist, a majority are thermal processes and have not been well-characterized for pasteurizing low-moisture foods. In addition, the nature of a low-moisture food matrix introduces various experimental complications that are not encountered in high-moisture foods. In this dissertation, the development, building instructions, and characterization of various open source tools for studying the inactivation kinetics of microorganisms in low-moisture foods are described. The first tool is the TDT Sandwich, a dry heating device for …

A Natural Antimicrobial From Bacillus Subtilis As A Biosanitizer For Resilient Membrane Biofilms, Pratishtha Verma

Electronic Theses and Dissertations

The microbial attachment and colonization on separation membranes lead to biofilm formation. Some selective isolates within the biofilm constitutive microflora acquire resistance and emerge predominant over prolonged use of the membrane. Thus, proving the cleaning and sanitization protocols to be ineffective in adequately removing resilient biofilms. This subsequently leads to selecting microbial resistance within the constitutive microflora to almost all antimicrobial treatments and hence, creates a need to develop novel alternative strategies to control biofilm formation on membrane surfaces. The first research project under this study was designed to understand the microbial interactions and emergence of predominance within biofilm constitutive …

The Exploration Of Nanotoxicological Copper And Interspecific Saccharomyces Hybrids, Matthew Joseph Winans Phd

Graduate Theses, Dissertations, and Problem Reports (ETD)

Nanotechnology takes advantage of cellular biology’s natural nanoscale operations by interacting with biomolecules differently than soluble or bulk materials, often altering normal cellular processes such as metabolism or growth. To gain a better understanding of how copper nanoparticles hybridized on cellulose fibers called carboxymethyl cellulose (CMC) affected growth of Saccharomyces cerevisiae, the mechanisms of toxicity were explored. Multiple methodologies covering genetics, proteomics, metallomics, and metabolomics were used during this investigation. The work that lead to this dissertation discovered that these cellulosic copper nanoparticles had a unique toxicity compared to copper. Further investigation suggested a possible ionic or molecular mimicry …

Comparison Of The Kinetic Parameters Of Escherichia Coli 0157:H7, Listeria Monocytogenes And Salmonella Typhimurium Derived From The Baranyi And Huang Models In A Chemically Defined Minimal Medium, Jose Isidro Fuentes

LSU Master's Theses

Microbial growth can be characterized by parameters such as lag time, growth rate, and maximum population density at any specific point of time. Mathematical models that predict microbial growth of foodborne pathogens are increasingly used in the food industry as a viable alternative to traditional methods of microbial enumeration. The Baranyi model has been widely used as the primary model of choice by many authors because of its performance and accuracy. The most recently developed Huang model has been less implemented and few comparisons between the Baranyi and Huang models have been made when modeling pathogenic growth. For this research, …

Understanding The Molecular Strategies Of Campylobacter Jejuni For Survival In Amoeba And Chicken., Deepti Pranay Samarth

Graduate Theses and Dissertations

Campylobacter jejuni endure to be major cause of gastroenteritis in humans worldwide. C. jejuni is fastidious in laboratory setup but can cause waterborne infection through contaminated water where none of these fastidious conditions are met. This dissertation presents an assortment of studies focused in reviewing three major factors which could present a helping hand to C. jejuni in its environmental survival viz. i) association with free-living amoebae (FLA) ii) horizontal gene transfer (HGT) contributing towards its genetic diversity iii). Viable but non-culturable (VBNC) state.

Acanthamoeba is a FLA linked to environmental survival of many intracellular pathogens, including C. jejuni. In …

Characterization Of Bacterial Isolates Obtained From Commercial Poultry Feed And Retail Food Using Whole Genome Sequence Analysis And Selected Biochemical Tests, Elena George Olson

Electronic Theses & Dissertations

The goals of this study is two-fold. The first part investigates bacterial isolates from commercial poultry feed and the second part deals with bacterial isolates recovered from retail food. In order to reduce pathogen contamination in poultry products identification of overall microbial populations in poultry production processing steps have always been considered an important monitoring tool for assessing sanitizer effectiveness and the corresponding responses of bacteria load levels on poultry carcasses. Bacterial isolates recovered from corn-based chicken feed were purified on aerobic plate count agar and eleven morphologically different colonies were selected for whole genome sequencing. In this part, the …

You Are What You Eat At Any Age: Carbon And Nitrogen Analysis Of Mummies From An Ancient Egyptian Necropolis, Stephen Funk, R. Paul Evans

Library/Life Sciences Undergraduate Poster Competition 2019

The BYU Egypt Project at Fag el-Gamus necropolis and adjacent Seila Pyramid has studied over 700 mummies excavated over the past 30 years. The necropolis includes an open area with densely located vertical burial shafts and a hill with horizontal burial shafts. The chronological and dietary history of the mummies was assessed using stable isotopy and 14C analysis of accessible biological samples.

Effect Of Environmental Factors And Residual Sanitizers On Survival And Attachment Of Indicator Organism And Human Pathogens On Fresh Produce, Vijay Singh Chhetri

LSU Doctoral Dissertations

A comprehensive understanding of the behavior of microbial contaminants on produce surfaces in agricultural farms and during post-harvest activities is essential for the development of produce safety risk management strategies. Our studies investigated the survival and the attachment of E. coli on watermelon surfaces in agricultural settings with different levels of vegetation, and the effect of residual sanitizers on the survival and the attachment of E. coli O157: H7 and L. monocytogenes on spinach leaves. The attachment strength (S_R) of the E. coli cells on watermelon surfaces significantly increased (P<0.05) from 0.04 to 0.99 in the first 24 h, which was primarily due to the decrease in loosely attached population, given that the population of strongly attached cells was constant. The daily die-off rate of E. coli ranged from -0.12 …

A Comparative Analysis Of The Fermentation Capabilities Of Various Bifidobacterium Strains, Ella Oney

Honors Program: Senior Projects (Public)

Bifidobacterium is a genus of anaerobic bacteria that are commonly found to inhabit the gastrointestinal tract of many members of the animal kingdom. These microorganisms are adapted to obtain their carbon from the breakdown of complex carbohydrates. Marmosets, a mammal whose gut microbiome is inhabited by high levels of Bifidobacteria, consume gum Arabic as a major part of their diet. The purpose of this experiment is to determine whether Bifidobacterium strains isolated from the guts of marmosets are able to degrade and ferment this complex carbohydrate or one of its main constituents, arabinose. This was accomplished by inoculating isolates of …

Hydrodynamic Cavitation As In-Line Process To Control Common Dairy Sporeformers, Pratibha Chaudhary

Electronic Theses and Dissertations

Sporeforming bacteria and their endospores have the ability to survive thermal treatments and proliferate in the milk and dairy products to cause spoilages. We applied the effect of hydrodynamic cavitation in controlling these bacteria and their spores at pilot scale level. Our aim was to investigate a technology that would improve the microbial quality of milk and dairy products, and is capable of being scaled up to be adapted at industrial level. Cavitation damages the cell walls of the bacteria and their endospores (releasing dipicolinic acid, responsible for endospore resistance to extreme conditions), thereby making them susceptible to thermal treatments …

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

Graduate 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 …

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

Graduate 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 …

Survival And Inactivation Of Salmonella Enterica And Human Norovirus On Consumer Contact Surfaces, Dorra Simmons

LSU Doctoral Dissertations

Salmonella enterica and human norovirus (HuNoV) are the leading cause of bacterial and viral gastroenteritis worldwide, respectively. One of the most important transmission routes of these pathogens is contaminated surfaces. In this study, we investigated the survival and the disinfection of Salmonella enterica serovar Typhimurium (S. Typhimurium) and HuNoV on selected consumer contact surfaces.

In the case of S. Typhimurium, formica laminate, stainless steel, and plastic cutting board surfaces were inoculated with different microbial loads of cells collected at log (6 h), stationary (24 h), or LTS (14 days) phases. The disinfection efficacy of two disinfectants (sodium hypochlorite or …

Delivering Entrapped Lactobacillus Plantarum Ncimb 8826 With Cereal-Legume Infant-Weaning Food To Improve Children's Gastrointestinal Health, Emmanuel Kyereh

LSU Doctoral Dissertations

Diarrhea remains the second leading cause of death among children under five globally, about one in five children’s deaths are attributable to it. In recent years,’ probiotics have been used as an alternative therapy measure to manage the situation. A promising delivery method that entraps probiotics in infant formula may help prevent or reduce diarrhea. The overall objectives of this study were to deliver entrapped Lactobacillus Plantarum NCIMB 8826 with maize-legume fortified complementary weaning food to reduce diarrhea and improve the gut microbiota. Both in vitro and in vivo models were used in this study and a mouse (C57BL/6 mice …

Microbiological Safety Assessment Of Fresh Fruits And Vegetables Collected From Main Markets Of Multan, Pakistan, Bina Rida, Farah Deeba

Journal of Bioresource Management

Most of the research related to food-borne human pathogens is conducted on the transmission of pathogens from foods of animal origin. However, recent studies showed that fruits and vegetables are the sources of many disease outbreaks. This study was carried out to assess the current knowledge and future developments for the microbial safety of fresh fruits and vegetables. The eight different fruits and vegetables, Grape (Vitis vinifera), Banana (Musa acuminate), Orange (Citrus sinensis), Apple (Malus domestica Borkh), Carrott (Daucus carota), Cucumber (Cucumis sativus), Green chili (Capsicum annuum …

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

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

This article focuses on breeding resistant strawberries to the fungus Verticillium dahliae, common name Verticillium wilt. This is a serious fungal disease that can result in a loss of 50% or more of a strawberry harvest when grown in infested soil. The main goal is to provide an example of how a cultivar can be made more resistant to a plant pathogen with the use of plant breeding methods.

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 …

Relationships Between Factors Influencing Biofilm Formation And Pathogen Retention In Complex Rhizosphere Microbial Communities, Aaron Coristine

Theses and Dissertations (Comprehensive)

Riparian wetlands are unique habitats facilitating all forms of life. The riverbanks of these environments provide ideal conditions for bacteria, plants, and higher organisms. Of particular interest to this research was the variation in microbial community structure at high, intermediate and poor water quality impacted areas. Assessing the capabilities of plants to retain microbial pathogens was identified. Root systems and corresponding soil are ideal locations for bacterial deposition, resulting in attachment at these areas. Biofilm production in these regions is important for long-term establishment, leading to persistence and potential naturalization. Opportunistic pathogens originating from mammalian fecal matter are introduced into …

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

Graduate 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 respective …

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

Graduate 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. …

Is Tb Testing Associated With Increased Blood Interferon-Gamma Levels?, Aideen E. Kennedy, Jim O'Mahony, Noel Byrne, John Macsharry, Riona G. Sayers

Department of Biological Sciences Publications

The Republic of Ireland reports a relatively low prevalence of Johne’s disease (JD) compared to international counterparts. Postulated reasons for this include a lower average herd size and a grass-based production system. Ireland also engages in high levels of bovine tuberculosis (bTB) testing. As interferon-gamma (IFN-γ) is believed to play a key role in protecting against JD, it is our hypothesis that administration of purified protein derivative (PPD), as part of the bTB test, is associated with a systemic increase in IFN-γ production, which may potentially limit clinical progression of the disease. We studied 265 cows (202 Friesian and 63 …

Persistence Of Enteric Viruses On Surfaces Under Varying Environmental Conditions, Nicole L. Turnage

Graduate Theses and Dissertations

Human enteric viruses such as human norovirus (hNoV) and Aichivirus A (AiV) are common foodborne viruses with hNoVs being identified as the leading causative agent of foodborne illnesses in the U.S. Moreover, hNoVs have been identified as the leading cause of nonbacterial acute gastroenteritis in the U.S. and worldwide. Fomite surface contamination is a major transmission route for enteric viruses. The application of an optimized virus recovery method from fomites is essential for better understanding of virus persistence under varying environmental conditions (EC). This study aimed to optimize a surface sampling method for virus recovery from nonporous food contact surfaces …