Food Microbiology Commons^™

The Physicochemical Properties Of Soy Protein Hydrolysate And Its Formulation And Stability With Encapsulated Probiotic, John Stricklin Edwards

Graduate Theses and Dissertations

Soy protein isolate (SPI) and probiotics can serve as a functional ingredient and beneficial supplement, respectively, to food formulations, but few studies focus on the compatibility of these two ingredients. The objective of this study was to prepare soy protein isolate (SPI) from defatted soybean flour and identify an optimal hydrolysis protocol to create soy protein hydrolysates (SPH) with improved solubility and functional properties and achieve an optimum encapsulation technique for probiotics and to determine the in vitro viability of encapsulated probiotic cells with SPH in a gastrointestinal environment. The SPI was prepared using an alkaline extraction procedure for solubility …

Effect Of Storage Temperature On The Survival Or Growth Of Listeria Monocytogenes On Whole And Fresh-Cut Produce, Juan F. Moreira Calix

LSU Master's Theses

Whole and fresh-cut produce are minimally processed and, therefore susceptible to microbial contamination. This study examined the survival or growth of Listeria monocytogenes on whole, and fresh-cut produce at different storage temperatures. Fresh fruits (cantaloupes, pears, pineapples, papayas, and watermelon) and vegetables (broccoli, cauliflower, lettuce, kale, and green bell peppers) were cut into 25 g pieces and were spot inoculated with 0.5 mL (8 Log CFU/mL) of Listeria monocytogenes. Inoculated fresh-cut samples were stored at 4°C or 13°C for 6 days. To represent the outer surface of the produce, cantaloupes and green bell pepper disks (20 cm2) were cut with …

Effect Of Processing On Microbiota Accessible Carbohydrates In Whole Grains, Caroline Smith

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

There is potential to increase microbiota accessible carbohydrates (MAC) in whole grains through food processing. Therefore, different processing conditions for boiling and extrusion of whole wheat flour were studied for their effect on MAC. Processing conditions had a minimal effect on fermentation response using 2 fecal samples of disparate composition. However, the processing method had an impact on the fermentation of non-digestible carbohydrates and subsequent short chain fatty acids production, but only for a microbiome with high diversity and a predominance of microbes associated with dietary fiber intake. Subsequently, five processing methods: boiling, extrusion, unleavened bread, yeast bread, and sourdough …

Prevalence And Control Of Salmonella Spp. And Sanitary Indicator Microorganisms In Wild Caught And Farm Raised Catfish (Ictalurus Punctatus), Bilan Costley Jessie

LSU Doctoral Dissertations

Catfish inspections have transitioned from the U.S. Food and Drug Administration (FDA) to the United States Department of Agriculture (USDA). The USDA Food Safety and Inspection Service (FSIS) and Food Emergency Response Network (FERN) consider it important to assess the food safety risk associated with consuming catfish in the United States. Surveillance of farm-raised and wild-caught catfish for pathogens is relevant as a public safety protocol. The purpose of this study was to detect the prevalence of Salmonella spp., identify and examine isolates for antibiotic resistance to clinical treatments, evaluate the effectiveness of antimicrobial chemical treatments against Salmonella enterica, and …

Modeling Of Free Chlorine Consumption And Escherichia Coli O157:H7 Cross-Contamination During Fresh-Cut Produce Wash Cycles, Mohammadreza Dehghan Abnavi, Ali Alradaan, Daniel Munther, Chandrasekhar R. Kothapalli, Partha Srinivasan

Mathematics and Statistics Faculty Publications

Controlling the free chlorine (FC) availability in wash water during sanitization of fresh produce enhances our ability to reduce microbial levels and prevent cross-contamination. However, maintaining an ideal concentration of FC that could prevent the risk of contamination within the wash system is still a technical challenge in the industry, indicating the need to better understand wash water chemistry dynamics. Using bench-scale experiments and modeling approaches, we developed a comprehensive mathematical model to predict the FC concentration during fresh-cut produce wash processes for different lettuce types (romaine, iceberg, green leaf, and red leaf), carrots, and green cabbage as well as …

Seaweeds As Nutraceuticals For Health And Nutrition, Emer Shannon, Nissreen Abu-Ghannam

Articles

Throughout human history, seaweeds have been used as food, folk remedies, dyes, and as mineral-rich fertilisers. Seaweeds as nutraceuticals or functional foods with dietary benefits beyond their fundamental macronutrient content are now a major research and industrial development concept. The occurrence of dietary and lifestyle related diseases, notably type 2 diabetes, obesity, cancer, and metabolic syndrome has become a health epidemic in developed countries. Global epidemiological studies have shown that countries where seaweed is consumed on a regular basis have significantly fewer instances of obesity and dietary-related disease. This review outlines recent developments in seaweed applications for human health from …

Evaluation Of Chilling Efficiency, Meat Tenderness, And Microbial Analysis Of Broiler Carcasses Using Sub-Zero Saline Solutions, Samira Viliani

Master's Theses

The poultry industry is seeking an advanced chilling system that can improve chilling efficiency, microbial safety, and water consumption without compromising meat quality. The objective of this study was to evaluate the effects of sub-zero saline chilling methods on chilling efficiency, breast fillet tenderness and microbial reduction of broiler carcasses. Following evisceration and rinsing, broiler carcasses were randomly assigned to one of three chilling solutions: 1) 0% salt or ice water control (0% NaCl/0.5^oC), 2) 3% salt (3% NaCl/-1.8^oC), and 3) 4% salt (4% NaCl/-2.41^oC) solutions. Broiler carcasses in sub-zero saline solutions reached the …

Occurrence Of Aflatoxin And Zearalenone In Concentrate Feeds And Milk Contamination With Aflatoxin M1 And Bacterial Pathogens In Malawi, Chunala Alexico Njombwa

LSU Doctoral Dissertations

Multiple studies were conducted in Malawi to: 1) evaluate knowledge and perception of dairy farmers towards molds, mycotoxins and associated adverse effects; 2) evaluate dairy farmers’ knowledge and perception on milk contamination, proper milk handling practices and adverse health effects associated with raw milk consumption; 3) determine levels of aflatoxins and zearalenone (ZEN) in concentrate feedstuffs; 4) assess prevalence and levels of aflatoxin M₁(AFM₁) in raw milk, dietary exposure and estimate HCC risks to children and adults; 5) assess Salmonella and E. colicontamination in raw and processed milk from selected small scale farms and major …

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, …

Selectivity Of Infrared Heat Treatment On Inactivation Of Mycotoxigenic Fungi On Stored Grain, Shantae A. Wilson

Graduate Theses and Dissertations

Selective Infrared (IR) heating holds great potential to decontaminate spores of unsafe fungi in corn. The objectives for this study were to investigate the impact of exposing corn to infrared energy at selected peak wavelengths (λ), infrared intensities and treatment durations, followed by tempering for further inactivation of microbes on the grain and explore a method for decontaminating Aspergillus flavus (A. flavus) spores on corn. Freshly harvested corn with initial moisture contents (IMCs) of 16%, 20%, and 24% wet basis (w.b.) were used. The corn samples were treated at different infrared wavelengths (3.2, 4.5, and 5.8 μm) for 20, 40 …

Potential Antimicrobials For Controlling Listeria Monocytogenes In Frankfurters, Aaron Rashad Bodie

Graduate Theses and Dissertations

Listeria monocytogenes is a pathogenic microorganism that causes Listeriosis. Listeriosis is a highly mortal disease with approximately 20% mortality rate. Listeria is psychrophilic, therefore it is able to survive in the refrigerator. This affects foods at cool storage such as fresh produce and RTE meats. To ensure the safety of RTE meat, post processing treatments are used such as vacuum packing, edible films, dip and treatment. One-way RTE can be treated is with the use of antimicrobials. However, in the past chemical substances were used. Currently, consumers want more natural and organic preservatives to combat health problems from toxic components …

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 …

Sustainability Assessment Of U.S. Beef Processing And Its Antimicrobial Systems, Shaobin Li

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

With the increasing meat demand and awareness of sustainability, concerns have been raised regarding the sustainability of beef production and processing. However, scarce data and inadequate sustainability assessment frameworks for the U.S. beef processing industry limit the ability to develop new technologies and policies comprehensively without shifting sustainability burdens. To fill those gaps, various assessments of the U.S. beef processing industry were conducted from multiple perspectives regarding the environmental, economic, microbial effectiveness of its antimicrobial systems, and human health impacts from foodborne illness, occupational hazards, and environmental pollution.

First, process-level water and energy usage at a typical large-size beef processing …

In Vitro And In Vivo (Mouse Model) Investigation Of The Efficacy Of Probiotic Bacteria Lactobacillus Casei And Lactobacillus Rhamnosus Incorporated In Tomato Juice, Bennett Atta Dzandu

LSU Doctoral Dissertations

Fruit and vegetable production in Ghana were estimated at 371,811 tons in 2017 with tomatoes ranked among the top four most cultivated vegetables. The majority of the production goes to waste due to spoilage and lack of processing. Probiotics have recently gained much attention owing to claims about their potential health benefits. However, the inability of certain probiotics to survive gastric conditions remain a potential setback. Tomatoes can be processed into value added products including those fortified with probiotics. Such value-added products can be used as protectant for the delivery of probiotics to improve gut health. The objective of this …

Use Of Gamma Irradiation As An Intervention Treatment To Inactivate Escherichia Coli O157:H7 In Freshly Extracted Apple Juice, Dielle Aurelia Fernandes

Food Science (MS) Theses

Escherichia coli O157:H7 can contaminate dropped apples used for juicing via contact with manure or fecally tainted irrigation water and attach to the flesh of the apple through bruises and wounds where surface sanitizers are not effective. The goal of this project was to determine the efficacy of gamma irradiation at the maximum allowed dose of 1000 Gy to inactivate Escherichia coli O157: H7 in whole apples used for juicing. Whole apples were punctured to simulate wounds which were then inoculated with an outbreak strain of E.coli O157:H7 and subjected to gamma irradiation at doses upto 1000 Gy. The D-value …

Antimicrobial Properties Of Different Chitosans Against Gram-Negative And Gram-Positive Foodborne Pathogens In Food Products, Nancy Katherine Rubio Zapata

LSU Doctoral Dissertations

Chitosan is a polymer derived of the deacetylation of chitin that is one of the most abundant material in nature. Chitosan solutions applied as edible coatings, and dipping solutions have shown positive results in the extension of shelf life on seafood and meat products. The purpose of this study was to evaluate the antimicrobial activities of a newly invented high molecular weight water-soluble (HMWWS) chitosan against selected Gram-negative (Salmonella Typhimurium, Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio cholerae) and Gram-positive (Listeria monocytogenes, Staphylococcus aureus, and Bacillus cereus) foodborne pathogens (initial inoculation of 6.5 Log). Chitosans with …

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 …

Improving The Food Safety Of Louisiana Strawberry Industry, Jose L. Brandao Delgado

LSU Doctoral Dissertations

Escherichia coli O157:H7, Salmonella sp., and Listeria monocytogenes have been linked to foodborne outbreaks in produce. The most recent outbreaks in produce have been associated with irrigation water due to infiltration of well water or water run-off from contaminated sources. The Food Safety Modernization Act (FSMA) requires all irrigation water to be safe for use on produce, as a strategy to reduce foodborne illnesses. A surfactant modified zeolite (SMZ) filtration system could provide produce farmers with a sustainable low-cost system for high-quality and safe irrigation water. The objective of this study was to evaluate the effectiveness of hexadecyltrimethylammonium …

Reducing The Risk: Psychological And Technological Approaches For Improving Handwashing Practices In The Foodservice Industry, Jeffrey Allan Clark

Graduate Theses and Dissertations

As Americans are spending greater portions of their dollar on food consumed outside the home, the foodservice industry plays more of an integral part of daily existence compared to previous generations. Given the numerous annual foodborne illness outbreaks that threaten human lives while undermining confidence in the food supply, food safety is a pertinent issue for industry stakeholders, government regulators, and consumers. Food worker handwashing reduces the risk of foodborne illness transmission, yet compliance with this simple behavior is a complex problem. This dissertation addresses, predominantly, the issue of sub-optimal handwashing practices through applying psychology and technology, including wearable computers …

Characterization And Evaluation Of The Probiotic Properties Of The Sporeforming Bacteria, Bacillus Coagulans Unique Is-2, Amy Garrison

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

Probiotics are live organisms, that when consumed in adequate amounts, confer a health benefit to the host. To achieve probiotic status, each potential strain’s functional properties and their safety to the consumer must be comprehensively evaluated. Probiotic effects have been observed to be strain specific, therefore each new strain of interest must be characterized according to their phenotypic and genetic characteristics. There is a list of characteristics that potential probiotic strains should have to be considered as a probiotic. Potential probiotic strains should be evaluated for their acid and bile salt resistance, antimicrobial activity and adherence and colonization to intestinal …