Food Microbiology Commons^™

Protein And Lipid Characterization Of Acheta Domesticus, Bombyx Mori, And Locusta Migratoria Dry Flours, Emily N. Brogan

Graduate Theses, Dissertations, and Problem Reports (ETD)

Cricket (Acheta domesticus), silkworm pupae (Bombyx mori), and locust (Locusta migratoria) dry flours were obtained to examine the biochemical properties and composition of the flours. This study aimed to characterize the protein and lipid components of three insect species utilizing proximate composition analyses, amino acid composition analysis, protein solubility, SDS-PAGE, fatty acid composition analysis, and thin layer chromatography to determine lipid classes, and lipid extraction efficiency. Kjeldahl determined the cricket, locust, and silkworm flours contained 72.0%, 53.1%, and 71.2% protein, respectively. All proximate composition analyses were significantly (p< 0.05) different between species. Amino acid composition analysis revealed that the flours contained 3.6-3.9% and 0.90-1.5% of lysine and methionine, respectively. Many countries have cereal grains and legumes as a staple in their diet that contain these limiting amino acids. Essential amino acids were 22% of total amino acids. Protein solubility revealed that the three species studied were most soluble in alkaline environments with highest protein solubility occurring at pH 13 at 66% solubility in silkworm. Lowest solubility occurred in more acidic conditions between pH 4-5. SDS-PAGE revealed five major protein fractions with estimated molecular weights of 27 (cuticle proteins), 41 (arginine kinase), which has been identified as an allergen in shrimp, 42 (actin), 71 (hemocyanin), and 220 myosin) kDa. Soxhlet extraction determined cricket, silkworm, and locust flours contained 15.4%, 33.3%, and 11.4% lipid, respectively. The only omega-3 fatty acid found in the flours was α-linolenic acid. Silkworm flour contained the most α-linolenic acid at 33.3% of total fatty acids, followed by locust (13.7%), and cricket (0.6%). TLC resolved lipids for typical lipid classes. The four major lipid classes noted were triacylglycerol, free fatty acid, cholesterol, and phospholipid. Lipid extraction efficiency found that the organic solvents chloroform and methanol had the highest lipid extraction yield in both cricket (69.3%) and locust (93.0%). Methyl-tertiary-butyl ether (MTBE) extracted lipids most efficiently in the silkworm. Proteins and lipids found in insects need to be isolated to further or commercial use.

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 …

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

Radiofrequency Processing For Inactivation Of Salmonella Spp. And Enterococcus Faecium Nrrl B-2354 In Whole Black Peppercorn And Ground Black Pepper, Xinyao Wei

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

Black pepper has been implicated in several foodborne illness outbreaks and food product recalls due to Salmonella contamination. Conventional decontamination methods for black pepper are challenged by harmful residues or quality deterioration. Radiofrequency (RF) heating reduces the come-up time which allows to design a high-temperature short-time processing to inactivate Salmonella with minimal deterioration in product quality. The objectives of this study were to investigate RF heating for inactivation of Salmonella in whole black peppercorn and ground black pepper samples, evaluate Enterococcus faecium NRRL B-2354 as a surrogate for Salmonella, and assess quality deterioration during RF heating of whole black peppercorn …

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. …

Evaluation Of The Impact Of Tart Cherries Polyphenols On The Human Gut Microbiota And Phenolic Metabolites In Vitro And In Vivo, Alba Claudia Mayta-Apaza

Graduate Theses and Dissertations

Tart cherries are polyphenol abundant stone fruits claimed to exert health benefits further of its nutritional properties. The abundant phytochemicals content in tart cherries also referred as dietary polyphenols have been considered as an effective natural antioxidant when added in daily diet. However, it has been hypothesized the intervention of gut microbiota on the overall functionality of such compounds. This thesis contains a wide-ranging literature review focused on tart cherry as a crop, current market, functional food, and several health benefits. Furthermore, the research done describes and in vitro and in vivo assays of a short-term dietary intervention of tart …

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 …

Effects Of Pre-Chiller Temperature On The Microbial Ecology Of Whole Bird Carcass Rinses, Rachael Elizabeth Blevins

Graduate Theses and Dissertations

Upon entering a poultry processing facility, birds are already contaminated with a variety of microorganisms. It is the responsibility of the processor to reduce these numbers to deliver a wholesome product to customers. This is not an easy task as there are ample opportunities for further microbial contamination. Some of these opportunities are obvious. For example, any areas where contaminants could be washed off one bird and onto another are always an area for concern, i.e. the scalder or the chiller. There are numerous opportunities for contamination that are not so obvious. These incidents of contamination are not necessarily due …

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 …

Hybrid Extended Kalman Filtering And Noise Statistics Optimization For Produce Wash State Estimation, Vahid Azimi, Daniel Munther, Seyed Abolfazl Fakoorian, Thang Tien Nguyen, Daniel J. Simon

Mathematics and Statistics Faculty Publications

Food-borne diseases associated with fresh produce consistently cause serious public health issues. Although sanitization measures are utilized to enhance the safety of fresh produce, strategies that neglect the dynamic nature of commercial wash processes are limited, creating the potential for pathogen cross-contamination and major disease outbreaks. In light of this risk, there is an urgent need for new control approaches during produce washing to reduce the probability of outbreaks. As an important step in this direction, a hybrid extended Kalman filter (HEKF) and particle swarm optimization (PSO)-based noise statistics optimization are designed for a produce wash system. The HEKF uses …

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 …

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 …

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. …

Validation Of Extrusion Processing For The Safety Of Low-Moisture Foods, Tushar Verma

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

Salmonella in low-moisture foods is an emerging challenge due to numerous food product recalls and foodborne illness outbreaks. The new Food Safety Modernization Act requires the food processors to validate their process controls that indeed kills the desired number of bacteria. This research had two major objectives: 1) Develop a response surface model for Salmonella inactivation during the extrusion of low-moisture food 2) Evaluate the use of Enterococcus faecium NRRL B-2354 as an adequate surrogate for Salmonella during the extrusion of low-moisture food. Oat flour was selected as a low-moisture food model. For inoculation, cocktail of five different strains of …

Modeling The Survival Of Salmonella In Soy Sauce-Based Products Stored At Two Different Temperatures, Ana Cristina Arciniega Castillo

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

Acidified foods are defined in the regulations as “low acid foods to which acid(s) has been added to bring finished pH to 4.6 or below”. As the market for these products expands, an increasing number of them are being processed with reduced heat treatment, relying on acid alone to ensure the destruction of pathogens. When considering the survival rate of microbial pathogens in these products, pH, water activity, temperature, salt content and holding time are integral and must be considered together.

Despite improvements in production, handling, and distribution of food products in recent years, protecting consumers from foodborne illness still …

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 …

Phylogenetic Diversity Of The Bacterial Communities In Craft Beer, Lindsey Rodhouse

Graduate Theses and Dissertations

The craft beer industry is increasing in popularity in the United States. The craft brewing process typically does not use a pasteurization step, therefore the boiling process is the primary critical control step. Any microorganisms introduced after boiling, or those that are not killed during boiling, are likely to participate in fermentation and persist in the final product. Previous culture-based studies have isolated bacteria and yeast from craft beers at specific time points, but little research has been done on the process as a whole. The objectives of this research are to (1) track bacteria development throughout the brewing process …