Life Sciences Commons^™

Understanding And Developing Safer Sanitation Agents And Strategies In Food Production Environments, Pragathi Kamarasu

Doctoral Dissertations

Food is a primary resource for survival of human beings, and it is also one of the primary resources for spread of infectious diseases. When both these factors come together it does not only cause ill effects on our health but also causes a burden on the food and agricultural industry. Through the help of science, us researchers and scientists have always tried to reduce this burden. And I hope like a drop of water in the ocean in some way my research contributes towards this. According to WHO currently in 2023 there are about 1 in 10 people falling …

Lactic Acid Bacteria Isolated From Fresh Vegetable Products: Potential Probiotic And Postbiotic Characteristics Including Immunomodulatory Effects, Fatima Khaled Alameri

Theses

The ability to perform effectively in the gastrointestinal system (GIT) is one of the most significant criteria for selecting the best probiotic bacteria. Thus, the present study aimed to investigate the potential probiotic characteristics of some selected lactic acid bacteria (LAB) isolated from vegetable products. Probiotic characteristics included tolerance to acid and bile, cholesterol removing ability, bile salt hydrolysis, resistance against lysozyme and antibiotics, production of exopolysaccharides (EPS), antimicrobial and hemolytic activities, and cell surface characteristics (auto-aggregation, co-aggregation, and hydrophobicity). Out of 46 isolates, 17 isolates that exhibited remarkable survivability under gastrointestinal conditions were selected for further analysis. Almost all …

Enhancement In Photoinactivation Of Food-Borne Pathogenic Bacteria With The Use Of Curcumin And Surfactants, Victor Ryu

Doctoral Dissertations

Photosensitizers and UV or visible light could photoinactivate bacteria. Curcumin was utilized as a food-grade photosensitizer, and an enhancement of its water-dispersibility, chemical stability, and antimicrobial activity when introduced into surfactant solutions was observed. Stock curcumin-surfactant solutions were prepared by titrating curcumin dissolved in ethanol into either Surfynol 465 or Tween 80 solutions (5 mM sodium citrate buffer). Stock curcumin surfactant solutions with different surfactant concentrations were diluted to 1 µM prior to irradiation. The resulting solutions also had surfactant concentrations below, near, and above their critical micelle concentrations (CMCs) of the respective surfactants. The antimicrobial activity of the curcumin-loaded …

Efficacy Of Selected Powdered Floor Treatments And Turmeric Rhizome Powder Against Salmonella, E. Coli, And L. Monocytogenes On Polyurethane-Concrete Flooring Material Carriers, Robert Sidney Fuller

Graduate Theses and Dissertations

The flooring in a food processing environment can become contaminated with pathogenic bacteria in many ways including foot and equipment traffic, incoming materials, and drain backups. Turmeric (Curcuma longa L.) rhizome powder and seventeen other commercially available powdered floor treatments with a variety of active ingredients including quaternary ammonium compounds (QAC), sodium percarbonate and similar perhydrates (SPC), urea, and borax, were investigated for reducing the levels of pathogens on flooring thereby reducing the risk of cross-contamination from the floor to food contact surfaces. Some of the commercially available floor treatments were Environmental Protection Agency (EPA) registered antimicrobials while others were …

Hemp Growth Factors And Extraction Methods Effect On Antimicrobial Activity Of Hemp Seed Oil: A Systematic Review, Klaudia Ostapczuk, Samuel Obeng Apori, Giovani Estrada, Furong Tian

Articles

The bioactive Hemp Seed Oil (HSO) is becoming very popular in the medical and research fields due to its antimicrobial properties against several diseases caused by bacteria and fungi. However, the effect of hemp-growing factors and extraction methods on the bioactivity of HSO does not receive adequate research attention. Therefore, this review aims to investigate the effect of growth factors and extraction methods on the antimicrobial activity of HSO. Articles were retrieved from Google Scholar and the Scopus database and screened against inclusion and exclusion criteria. The study revealed that HSO prefers warm climates and favorable humidity ranging from 20 …

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 …

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 …

Use Of Different Ripening Inhibitors To Enhance Antimicrobial Activity Of Essential Oil Nanoemulsion, Victor Ryu

Masters Theses

The objective of this research was to study the impact of ripening inhibitor level and type on the formation, stability, and activity of antimicrobial thyme oil nanoemulsions formed by spontaneous emulsification. Oil-in-water antimicrobial nanoemulsions (10 wt%) were formed by titrating a mixture of essential oil, ripening inhibitor, and surfactant (Tween 80) into 5mM sodium citrate buffer (pH 3.5). Stable nanoemulsions containing small droplets (d < 70 nm) were formed. The antimicrobial activity of the nanoemulsions decreased with increasing ripening inhibitor concentration, which was attributed to a reduction in the amount of hydrophobic antimicrobial constituents transferred to the separated hydrophobic domain, mimicking bacterial cell membranes, by using dialysis and chromatography. The antimicrobial activity of the nanoemulsions also depended on the nature of the ripening inhibitor used: palm ≈ corn > canola > coconut which also depended on their ability to transfer hydrophobic antimicrobial constituents to the separated hydrophobic domain.

Influence Of Biomimetic Chelating Packaging On Natural Antimicrobial Efficacy, Paul Castrale

Masters Theses

The iron chelating molecule, ethylenediaminetetraacetic acid (EDTA) is used in food applications for the preservation of oxidation prone ingredients. Research has suggested that EDTA is also capable of enhancing the antimicrobial effectiveness of various compounds including naturally-derived antimicrobials. With consumer demand for cleaner food labels, there remains an opportunity to introduce new chelating technology to replace synthetically-derived EDTA. Through photographting and chemical conversion, hydroxamic acid ligands were covalently bound to polypropylene films resulting in polypropylene-graft-poly(hydroxamic acid) (PP-g-PHA). The resulting films demonstrated an ability to chelate 64 nmol/cm² from an iron saturated environment or 163 nmol/cm …

Switchgrass Extractives Have Potential As A Value-Added Antimicrobial Against Plant Pathogens And Foodborne Pathogens, Alexander Ian Bruce

Masters Theses

Panicum virgatum (switchgrass), a perennial grass native to North America, is a leading biomass feedstock candidate for the manufacture of cellulosic ethanol. Switchgrass is considered a viable option for biofuel production due to its cheap production cost and ability to grow on marginal land. Biofuel derived from switchgrass has been shown to be very energy efficient, producing 540% more renewable energy versus nonrenewable energy expended. Switchgrass-derived biofuel is also estimated to have greenhouse gas emissions that are 94% lower than emissions from gasoline (Schmer et al 2008). Biofuels are created through biochemical processes that utilize various enzymes and microorganisms for …

Antimicrobial Inhibitory Activities Of Phenolic Extracts From Four Selected Soybean Hulls In Culture And Chicken Skin Model Systems, And Preliminary Ace-Inhibitory Activity, Rajaa Abdulkair Abutheraa

Graduate Theses and Dissertations

Soybean components provide health benefits to humans. Soybean hulls, a major by-product of the soybean processing industry consist of complex carbohydrates, proteins, lipids and polyphenols such as anthocyanidins, proanthocyanidins and isoflavones. The polyphenolic compounds in the hulls give them various colors such as black, brown, green, yellow or even a mottled appearance. Studies have reported different soybean varieties with varying total phenolic compounds in their seed hulls, which have antioxidant property. Phenolic extracts can be used as substitutes for synthetic antimicrobials and preservatives to assist in preventing the growth of pathogens such as Salmonella Typhimurium, E coli 0157:H7, and Campylobacter …

Physicochemical And Toxicological Assessment Of Antimicrobial Ε-Polylysine-Pectin Complexes, Cynthia L. Lopez Pena

Doctoral Dissertations

ε-Polylysine is an appealing FDA-approved, all natural antimicrobial biopolymer effective against a wide range of microorganisms. Its implementation is greatly limited by its strong cationic charge, which has been linked to instability in food systems, perceived astringency and bitterness, and the ability to inhibit lipid digestion. Previous studies have shown that controlled complexation of ε-polylysine with anionic pectin is able to prevent instability and astringency in simplified model food systems, while maintaining the antimicrobial character of polylysine. Isothermal titration calorimetry, micro-electrophoresis, microscopy, and turbidity analyses of the stability of electrostatic pectin-polylysine complexes in the presence of strongly anionic κ-carrageenan, and …

Concomitant Uptake Of Antimicrobials And Salmonella In Soil And Into Lettuce Following Wastewater Irrigation, J. Brett Sallach, Yuping Zhang, Laurie Hodges, Daniel D. Snow, Xu Li, Shannon L. Bartelt-Hunt

Department of Civil and Environmental Engineering: Faculty Publications

The use of wastewater for irrigation may introduce antimicrobials and human pathogens into the food supply through vegetative uptake. The objective of this study was to investigate the uptake of three antimicrobials and Salmonella in two lettuce cultivars. After repeated subirrigation with synthetic wastewater, lettuce leaves and soil were collected at three sequential harvests. The internalization frequency of Salmonella in lettuce was low. A soil horizon-influenced Salmonella concentration gradient was determined with concentrations in bottom soil 2 log CFU/g higher than in top soil. Lincomycin and sulfamethoxazole were recovered from lettuce leaves at concentrations as high as 822 ng/g and …

Enhancement Of Antimicrobial Activity Of Naturally Occuring Phenolic Compounds By Nano-Particle Mediated Delivery Against Listeria Monocytogenes, Escherichia Coli O157:H7, And Salmonella Typhimurium, Madhuram Ravichandran

Graduate Theses and Dissertations

Food-borne illnesses are of major concern in the U.S. and worldwide. Salmonella,Listeria,E. coli O157:H7 continue to be some of the major foodborne pathogens. Recurring recalls due to these pathogens demand critical antimicrobial strategies to decontaminate the food through its procession from farm to fork. In our study, we combined the effectiveness of naturally occurring phenolic compounds individually, with/ without ethylenediamine tetraacetic acid (EDTA) and/or Nisin and nanoparticle delivery to improve the antimicrobial potential of the compounds against Listeria monocytogenes (L.m.), Salmonella Typhimurium (S.T.), and Escherichia coli O157:H7 (E.c.), in brain …

Aqueous Extracts Of Hibiscus Sabdariffa As Antimicrobials In Foods, Kristen Liane Higginbotham

Masters Theses

Hibiscus sabdariffa L. is a tropical shrub species cultivated in multiple countries and is mainly produced for its red calyces that are used for a tea beverage. Aqueous, lyophilized extracts of Hibiscus were examined for their chemical composition and antimicrobial activity against Escherichia coli O157:H7, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), and Listeria monocytogenes.

Lyophilized, dialyzed extracts of commercially aquired calyces were examined in microbiological medium and milk at various fat levels for antimicrobial activity against E. coli O157:H7 and S.aureus. Extracts were either filtered or autoclaved to sterilize and tested in microbiological medium. Autoclaved extracts were more effective …

Isolation And Partial Characterization Of Bioactive Fucoxanthin From Himanthalia Elongata Brown Seaweed: A Tlc-Based Approach, Gaurav Rajauria, Nissreen Abu-Ghannam

Articles

Seaweeds are important sources of carotenoids, and numerous studies have shown the beneficial effects of these pigments on human health. In the present study, Himanthalia elongata brown seaweed was extracted with a mixture of low polarity solvents, and the crude extract was separated using analytical thin-layer chromatography (TLC).The separated compounds were tested for their potential antioxidant capacity and antimicrobial activity against Listeria monocytogenes bacteria using TLC bioautography approach. For bio-autography, the coloured band on TLC chromatogram was visualized after spraying with DPPH and triphenyltetrazolium chloride reagents which screen antioxidant and antimicrobial compounds, respectively, and only one active compound was screened …

Antimicrobial Efficacy Of Edible Soy Protein Isolate Films And Coatings Incorporated With Hop Ethanol Extract And The Influence On Shelf-Life And Sensory Attributes Of Bologna, Jamie R. G. Skudlarek

Theses and Dissertations--Animal and Food Sciences

There is demand for improved security of refrigerated ready-to-eat meats. Antimicrobial edible films and coatings could function as an added barrier against post-processing contamination. Hops and hop extracts are known for their antimicrobial efficacy which is attributed to key antimicrobial components including humulones, lupulones, xanthohumol and various terpenoids. Yet, hop ethanol extract has not been studied as an antimicrobial to incorporate into edible protein films and/or coatings. The overall objective of this research was to evaluate hop ethanol extract as an antimicrobial agent incorporated into edible soy protein isolate (SPI) films and coatings, and the influence on the shelf-life and …

The Antimicrobial Activity Of Cold Pressed Terpeneless Valencia Orange Oil At Cold Temperatures, Sean Jeffrey Pendleton

Graduate Theses and Dissertations

This research was undertaken to identify an antimicrobial for use during chilling in beef processing, including periods of temperature abuse, as well as to evaluate membrane filtration as means to remove essential oils from bacteria to prevent further antibacterial action. Cold pressed terpeneless Valencia orange oil was examined in combination with various temperatures (37°C, 10°C, and 4°C) to determine its antimicrobial activity against various strains of bacteria. The strains were tested using a ninety-six well microtiter plate method, with or without membrane filtration. The compound 2, 3, 5-triphenyl tetrazolium chloride was used as a growth indicator. Serial, two fold dilutions …

Antimicrobial Activity Of Plant Essential Oils Using Food Model Media: Efficacy, Synergistic Potential And Interaction With Food Components, Jorge Gutierrez, Catherine Barry-Ryan, Paula Bourke

Articles

The aim of this study was to optimise the antimicrobial efficacy of plant essential oils (EOs) for control of Listeria spp. and spoilage bacteria using food model media based on lettuce, meat and milk. The EOs evaluated were lemon balm, marjoram, oregano and thyme and their minimum inhibitory concentrations (MIC) were determined against Enterobacter spp., Listeria spp., Lactobacillus spp., and Pseudomonas spp. using the agar dilution method and/or the absorbance based microplate assay. MICs were significantly lower in lettuce and beef media than in TSB. Listeria strains were more sensitive than spoilage bacteria, and oregano and thyme were the most …

The Anti-Microbial Efficacy Of Plant Essential Oil Combinations And Interactions With Food Ingredients, Jorge Gutierrez, Catherine Barry-Ryan, Paula Bourke

Articles

The objective of this study was to evaluate the efficacy of plant essential oils (EOs) in combination and to investigate the effect of food ingredients on their efficacy. The EOs assessed in combination included basil, lemon balm, marjoram, oregano, rosemary, sage and thyme. Combinations of EOs were initially screened against Bacillus cereus, Escherichia coli, Listeria monocytogenes and Pseudomonas aeruginosa using the spot-on-agar test. The influence of varying concentrations of EO combinations on efficacy was also monitored using E. coli. These preliminary studies showed promising results for oregano in combination with basil, thyme or marjoram. The checkerboard method was then used …

Colloidal Particles As Antimicrobial Carrier Systems, Dustin W. Carnahan

Masters Theses 1911 - February 2014

The objective of this thesis is to develop a method by which antimicrobials are delivered into a food product as a concentrated dose to the specific area in which the microorganism is growing without interference from the food matrix. More specifically, we plan to achieve this by delivering the antimicrobials nisin and lysozyme attached to nanoparticles and emulsion droplets. We hypothesize that (a) the attachment to a delivery vessel may increase the local concentration of the antimicrobial in the vicinity of the bacterial pathogens and (b) that the size and charge of the nanoparticle following attachment of the antimicrobials will …