Life Sciences Commons^™

Antimicrobial Activity Of Essential Oils And Their Components Against Lactic Acid Bacteria, Laurel Dunn Gann

Masters Theses

Efficacy of plant essential oils against spoilage lactic acid bacteria was examined using two different study methods with the goal of determining minimum inhibitory (MIC) and minimum lethal concentrations (MLC) of the essential oils. The initial study included the incorporation of the essential oils, or their major constituents, into agar to allow uniform dispersion of the substance throughout an agar surface. Individual cultures of nine lactic acid bacteria species (Pediococcus acidilactici, Pediococcus damnosus, Lactobacillus fermentum, Lactobacillus fructivorans, Lactobacillus brevis, Lactobacillus buchneri, Lactobacillus plantarum, Leuconostoc mesenteroides, and Leuconostoc citrovorum) were spot …

Inhibition Of Spoilage Yeasts Using Spice Essential Oils And Their Components, Audra Ann Wallis

Masters Theses

Clove bud, cinnamon bark, and thyme oil, along with their components cinnamaldehyde, cinnamic acid, eugenol, carvacrol, and thymol, are widely acknowledged to have antimicrobial properties against bacteria. However, less is know about the inhibitory properties of essential oil components against spoilage yeasts. In this study a minimum inhibitory concentration (MIC) for these essential oils and components was determined using an agar dilution assay for Torulaspora delbrueckii, Candida krusei, Schizosaccharomyces pombe and Zygosaccharomyces bailii. The efficacy of essential oil components eugenol, carvacrol, cinnamaldehyde and thymol then were evaluated in a model salad dressing. The MIC against all yeasts for cinnamaldehyde and …

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 …

A Comparison Of Salmonella Enterica Serovars: Are Prevalence, Virulence And Responses To Environmental Conditions Serovar Or Strain Dependent?, Nan Zhang

Masters Theses

Salmonella are considered the leading cause of foodborne illnesses with frequent outbreaks in United States. While more than 2500 serovars have been identified, Salmonella Typhimurium and Salmonella Enteritidis are primarily responsible for most human infections while Salmonella Kentucky and Salmonella Heidelburg are currently the most prevalent serovars associated with poultry contamination. The relationship between virulence and prevalence is not fully understood, but may be a result of environmental stress exposure such as acid stress. In this research, organic acid (acetate) and inorganic acid (hydrogen chloride) were applied to 15 different serovars isolated from human infections or poultry. The growth curves …

Transparent Dispersions Of Milk Fat-Based Solid Lipid Nanoparticles For Delivery Of Beta-Carotene, Linhan Zhang

Masters Theses

Solid lipid nanoparticles (SLNs) are a category of delivery systems applicable to various bioactive compounds in the food industry. Compared to conventional emulsions that have a fluidic oil phase, the mobility and release of bioactive compounds can be controlled by encapsulation in the solid lipid matrix with appropriate properties. Common approaches of preparing SLNs are high energy methods and solvent evaporation methods, which have can lead to degradation of compounds during processing and residues of organic solvent, respectively. In this thesis, a low energy approach based on the phase inversion temperature method has been used to prepare SLNs based on …

Chemical Disinfectants For Inactivation Of Human Norovirus Surrogates, Cong Cao

Masters Theses

Human noroviruses (HNoVs) are considered the leading cause of acute non-bacterial gastroenteritis worldwide. Effective chemical disinfectants to inactivate HNoVs are needed. Since HNoVs cannot be cultivated in the lab, cultivable surrogates, feline calicivirus (FCV-F9) and murine norovirus (MNV-1), are used to determine inactivation using infectivity plaque assays. This study aimed to: 1) determine the ability of benzalkonium chloride (BAC) and potassium peroxymonosulfate (KPMS) to inactivate FCV-F9 and MNV-1 in vitro using suspension and carrier tests under clean and simulated dirty (5% fetal bovine serum) conditions over 1 h at room temperature; 2) determine inactivation of FCV-F9 and MNV-1 in suspension …