Food Microbiology Commons^™

Characteristics Of Yogurt And Culture Bacteria As Affected By Ingredients That Help Treat Leaky Gut, Ricardo Jose Santos Aleman

LSU Doctoral Dissertations

At least 100 million people have leaky gut syndrome. This syndrome is associated with multiple health problems such as diabetes, celiac disease, asthma, multiple sclerosis, and inflammatory bowel disease, costing more than $3 billion per year to treat. L-Glutamine, quercetin, slippery elm bark, marshmallow root, N-acetyl-d-glucosamine (NAG), licorice root, maitake mushrooms, and zinc orotate have been reported to help treat leaky gut.

The objectives were to explore the characteristics of yogurt and culture bacteria as affected by ingredients that help treat leaky gut. In yogurt, the pH, titratable acidity, syneresis, viscosity, color, Streptococcus thermophilus, Lactobacillus bulgaricus, yeast and mold and …

Effect Of Type Of Mulch And Biological Soil Amendments Of Animal Origin (Bsaao) On Microbial Food Safety Risk On Cucumbers And Carrots Irrigated With Contaminated Or Chlorinated Water, Juan Fernando Moreira Calix

LSU Doctoral Dissertations

A comprehensive understanding of the effect biological soil amendments of animal origin and physical soil amendments have on produce contamination is important for developing strategies to mitigate this risk. Our studies investigated the persistence of generic E. coli, E. coli O157:H7 and Salmonella spp. in soil and produce surfaces with different BSAAO and mulch applications, as well as the effectiveness of chlorine treatments in reducing enteric bacteria in the field. Cucumbers harvested from plots with paper mulch had the highest levels of E. coli (3.76 Log CFU/cm²) while samples from maize mulch had the lowest levels (1.68 …

Influence Of Hesperidin On The Physico-Chemical, Microbiological, And Sensory Characteristics Of Frozen Yogurt, Roberto Antonio Cedillos Hernández

LSU Master's Theses

Frozen yogurts contain yogurt culture bacteria which might impart health benefits to its consumers. Global frozen yogurt market sales are expected to grow 4.8% by 2028 which represents an important opportunity for the industry, consumers, and researchers. Polyphenols are metabolites found in plants which have antioxidant and anti-inflammatory properties and might prevent chronical diseases such as cancer, diabetes, and cardiovascular diseases. The objective of this study was to elucidate the effect of the polyphenol hesperidin on the physico-chemical, microbiological, and sensory characteristics of frozen yogurts. Hesperidin was incorporated in frozen yogurt at three concentrations (500, 250 and 125 mg/90g of …

Development Of A Non-Dairy Yogurt Alternative Using High Protein Brown And White Rice Flour, Anita Morris

LSU Doctoral Dissertations

There is a great demand for plant-based yogurt alternatives (YAs) due to societal prevalence of milk sensitivities and allergies as well as some consumers abstaining from animal-derived products. Producing YAs from rice flour has considerable potential because (1) rice is not a major food allergen, (2) using rice flour is more economical compared to plant milks, the main ingredient in commercially available YAs, and (3) there are no rice-based yogurt alternatives in today’s marketplace. The overall goals of this study were to develop probiotic YAs from brown and white rice flours, and to evaluate their storage stability, probiotic’s survival in …

Producing Bacterial Cellulose From Coffee (Coffea Arabica) Kombucha Fermentation And Assessment Of Its Efficacy To Remove Pathogenic Bacteria From Contaminated Water And A Pollutant Dye From Aqueous Solution, Federico Bueno

LSU Doctoral Dissertations

Bacterial cellulose (BC), composed of cellulosic nanofibrils, is synthesized by a symbiotic culture of bacteria and yeast during the fermentation of coffee kombucha (CK). BC may be used as a purification agent and adsorbent. The overall goal of this project was to synthesize BC from CK fermentation and assess its efficacy in removing pathogenic bacteria from contaminated water and a pollutant dye from aqueous solution. The objectives of this study were to: (1) compare BCs that were produced from different carbohydrate substrates in the fermentation of CK, (2) characterize dried BCs produced using various drying methods, (3) evaluate BC as …

Fish Gelatin Coating As An Antimicrobial Agent On Wild-Caught Louisiana Shrimp, Hunter S. Songy

LSU Master's Theses

Seafood has a short shelf-life because of its unstable nature. Shrimp has a shelf-life of only eight days. Edible coatings, like those made from gelatin, have been used to apply antimicrobial agents to food product surfaces. Organic acids are naturally occurring, low-cost options that have been proven to effectively reduce bacterial loads on food products and extend their shelf-life. Gelatin can be extracted from catfish skin, helping to reduce product waste. The purpose of this study was to determine the potential effectiveness of fish skin gelatin as an antimicrobial coating alone and in combination with lactic acid, and then compare …

Evaluation Of The Effectiveness Of Aeration During Washing To Dislodge Microorganisms From Cucumbers And Bell Peppers, Julysa Benitez

LSU Master's Theses

Microorganisms may attach firmly to produce matrices and could affect the efficacy of disinfectants. The purpose of this study is to evaluate the effectiveness of aeration to reduce microbial risk during washing and sanitizing of fresh produce. Bell peppers and cucumbers were spot inoculated with Listeria innocua, E. coli O157:H7, and Salmonella; after drying in the biosafety cabinet for 1h, these were washed with water or sanitized with 100 ppm of chlorine for 3 min with or without aeration. Bell pepper and cucumber samples were placed in sterile bags with PBS after treatment. Bell peppers were processed in the stomacher …

Effect Of Contact Time And Attachment Level Of Bacterial Pathogens On Efficacy Of Chlorine Treatment In Fresh Produce, Jyoti Aryal

LSU Master's Theses

Bacterial attachment or biofilm formation on produce surfaces may result in limited penetration ability of sanitizers. This study examined the wet and dry contact time (WCT or DCT) of produce during washing with sanitizer and evaluated the effect of attachment level of Listeria monocytogenes during storage on the efficacy of chlorine treatment. Spinach and bell peppers were inoculated with Listeria monocytogenes and Salmonella enterica. The produce was then washed by dipping into a 100 ppm of chlorine solution for 1 min and an additional 1, 3, or 5 minutes (WCT) or removed from the chlorine solution and held for 1, …

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 …

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 …

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, …

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 …

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 …

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 …

Efficacy Of Aqueous And Gaseous Chlorine Dioxide In Reducing Salmonella, E. Coli O157:H7, And Listeria Monocytogenes On Sweet Potatoes, Strawberries, And Blueberries, Phillip Luu

LSU Master's Theses

Chlorine dioxide, a stronger oxidizing agent, is effective against a broad spectrum of microorganisms. This study evaluated the efficacy of chlorine dioxide on reducing Salmonella, E. coli O157:H7, and Listeria monocytogenes on sweet potato (aqueous ClO₂), strawberries and blueberries (gaseous ClO₂). Sweet potatoes inoculated with multi-strain cocktails of each bacterial pathogen (10⁷ CFU/cm²) were treated with 5 ppm aqueous ClO₂ or water for 10, 20, and 30 minutes. Strawberries and blueberries spot inoculated with multi-strain cocktails of each bacterial pathogen (10⁷ CFU/g) were treated with gaseous ClO₂ sachets (63 mg/l for strawberry and 30 mg/l for blueberry) …

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 …

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 …

Evaluating The Effect Of Chitosan, Water-Soluble Chitosan And Chitosan Application Techniques On The Quality Of Refrigerated Catfish Fillets, Franklin Bonilla Torres

LSU Master's Theses

Chitosan (CH) is a biopolymer synthetized by deacetylation of chitin, it is found in the exoskeleton of crustaceans, cell wall of fungi, and insects. CH’s water insolubility limited the used of this compound in some food systems. However, enzymatic hydrolysis of CH yields water-soluble chitosan (WSC). The aim of this study was to evaluate the effect of chitosan, water-soluble chitosan, and chitosan application techniques on the quality of refrigerated catfish fillets. This research was conducted in two separated studies. In the first study, three solution treatments were prepared: (1) a 1% acetic acid (AA) solution, (2) a 0.5% CH solution …

Effect Of Hot Water Conditioning On Microbial Safety And Quality Of In-Shell Pecans, Karuna Kharel

LSU Master's Theses

Hot water conditioning of in-shell pecans is one common practice followed by industries to facilitate shelling. It also acts as a preventive control for potential microbiological contamination that might occur during pre- and post-harvest processes. However, heat treatment may have an effect on the eating quality of nuts. The main objectives of the study were to develop a post-harvest hot water treatment intervention as a kill step to destroy foodborne pathogens on in-shell pecans and evaluate the effect of treatments on physicochemical properties, consumer acceptance and purchase intent of dehulled and roasted pecans. The time (1-5 min) and temperature (70, …

Heat, Acid And Osmotic Stress Tolerance Of Leuconostoc Mesenteroides As Influenced By Prior Exposure To Various Mild Stress Conditions, Ingrid C. Osorio Rodriguez

LSU Master's Theses

The importance of Leuconostoc mesenteroides is recognized for its contribution to taste in cultured dairy products. It has been cited for its potential role as a probiotic. Consumer demand exists for new dairy products with health benefits. In the manufacture of probiotic-products survival of Leuconostoc mesenteroides would depend on its ability to tolerate challenging processing and storage conditions. Improved viability by prior exposure to mild stresses can increase stress tolerance toward a more severe stress. Furthermore, it can result in cross-protection due to connection of several proteins in response to stresses. Objective was to evaluate the effect of prior …

Interaction Of Cocoa Powder With Intestinal Microbiota, Martha M. Escoto Sabillon

LSU Master's Theses

Cocoa is the fully fermented and dried seed of the cacao tree (Theobroma cacao L.) which has prebiotic properties, due to their high concentration of polyphenols. Therefore, the ingestion of cocoa could cause changes in the proportions of the intestinal microbiota that can influence the intestinal immune response. The objective of this study was to determine the effect of alkalization process of the cocoa bean in the diversity of the gut microbiota. The samples were “lavado” unprocessed cocoa powder, “natural” unprocessed cocoa powder, “D-11-S” as alkalized cocoa powder, “D-11-B” heavily alkalized cocoa powder, and raw cocoa “shells” and a control …

Isolation, Detection, And Prevention Of Foodborne Bacteria In Irrigation Water And Dairy Food, Mohammed Saleemallah Alhejaili

LSU Doctoral Dissertations

Foodborne microorganisms can be beneficial to humans or cause disease. Salmonella is one of the most causative foodborne disease outbreaks in the U.S.A. Salmonella has been detected in surface water used in irrigation, and can survive for weeks to years in water. The purpose of the study was to detect low levels of Salmonella spp. by comparing surfactant modified zeolite (SMZ) filtration and Activated Carbon (AC) filtration with the Environmental Protection Agency (EPA) method 1200. Also, to determine the generic E.coli counts and if there was a direct correlation of Salmonella to generic E. coli in irrigation water. The EPA …

A Preliminary Study To Evaluate Issues Involved Under In Vivo Conditions Of A Delivery System Containing Immobilized Lactobacillus Plantarum Ncimb 8826 On Rice Bran Fiber Extract, Chen Liu

LSU Master's Theses

Gut diseases like diarrhea, irritable bowel symptoms, and inflammatory bowel disease (IBD) can be treated with probiotics therapy. Probiotics have been recognized for their ability to promote the development of gut health and improve immune system. However, a difficulty involved with the use of probiotics is the need for and the ability to deliver a sufficient concentration of viable probiotic to the appropriate site. This can be difficult since the most common (and probably easiest) method of delivering the probiotic is orally. As such, the probiotic must be capable of surviving the hostile conditions of passage through the G.I. tract. …