Food Microbiology Commons^™

Development Of A Predictive Modeling System For Validation Of The Cumulative Mirobial Inactivation Of The Salmonellae In Pepperoni Utilizing A Non-Pathogenic Surrogate Microorganism (Enterococcus Faecalis), Scott Donald Stillwell

Graduate Theses and Dissertations

Salmonellosis is the most frequently occurring bacterial foodborne illness in the United States and the human case rate has not improved for the past two decades. The federal agency responsible for oversight of meat and poultry processors has announced the intent to extend existing pathogen reduction performance standards for Salmonella spp. to cover all classes of products including fermented sausages that are currently produced under HACCP plans that are validated for control of Escherichia coli O157:H7. The proposed regulatory modifications will require processors to revalidate HACCP plan controls to achieve either a 6.5 or a 7.0 log10 inactivation of the …

A Single Point Mutation In The Listerial Betl Sigma(A)-Dependent Promoter Leads To Improved Osmo- And Chill-Tolerance And A Morphological Shift At Elevated Osmolarity, Ronald F. Hoffman, Susan Mclernon, Audrey Feeney, Colin Hill, Roy D. Sleator

Department of Biological Sciences Publications

Betaine uptake in Listeria monocytogenes is mediated by three independent transport systems, the simplest of which in genetic terms is the secondary transporter BetL. Using a random mutagenesis approach, based on the E. coli XL1 Red mutator strain, we identified a single point mutation in a putative promoter region upstream of the BetL coding region which leads to a significant increase in betL transcript levels under osmo- and chill-stress conditions and a concomitant increase in stress tolerance. Furthermore, the mutation appears to counter the heretofore unreported “twisted” cell morphology observed for L. monocytogenes grown at elevated osmolarities in tryptone soy …

Aqueous Extract Of Nigella Sativa Seeds Suppresses Testicular Steroidogenesis In Mice Leydig Cells In Vitro., 5sheikh A. Saeed, Naheed Anwar, Qaiser Jabeen, Anwar Hassan Gilani

Department of Biological & Biomedical Sciences

10ABSTRACT 11Nigella sativa (black seed) is an important medicinal herb with folkloric use in wide range of diseases. It is 12well studied for its biological activities. However, there is limited information regarding its effect on the 13male reproductive system. This study describes the effect of the aqueous extract of N. sativa (NSE) on 14 testicular steroidogenesis from mice Leydig cells in vitro. Mice testicular cells were incubated in a media 15 containing either no treatment or NSE or LH alone or combination of LH and NSE. Incubations were 16 carried out for three hours in a shaking water bath at …

Innovative Food Product Development Using Molecular Gastronomy: A Focus On Flavour And Sensory Evaluation, Mark Traynor

Doctoral

The primary goal of this research was to develop novel ice cream products using the principles of molecular gastronomy. An ice cream model system (emulsion) was developed, in which the effects of ingredient levels on stability and formation were investigated and optimised using Response Surface Methodology (RSM). Two characteristic volatiles of banana (isoamyl acetate and furfuryl acetate) were added to the optimised emulsion, and their headspace emission was quantified using Solid Phase Microextraction with Gas Chromatography Mass Spectrometry. RSM was used to investigate the main and interactive effects of ingredient, salt and pH levels on the headspace emission of these …

Optimization Of Fermentation Conditions For The Utilization Of Brewing Waste To Develop A Nutraceutical Rich Liquid Product, Shilpi Gupta, Amit Jaiswal, Nissreen Abu-Ghannam

Articles

Utilization of brewers’ spent grain (BSG), for the development of a fermented liquid product rich in value-added phenolic compounds was investigated. Changes in and liberation of phenolic compounds and antioxidant activity during fermentation of BSG was studied. The effect of various particle size (PS), solid liquid (SL) ratio, fermentation time and rotation speed was optimized using response surface methodology (RSM) for the purpose of improving bacterial growth and the enhancement in the release of polyphenolic compounds. Contour maps generated using the response surface equation showed that the experimental variables significantly affected the response. A production of 10.4 log cfu/ml, 2.95 …

Utilisation Of Spent Dairy Yeast Kluyveromyces Marxianus For The Production Of Flavoured Yeast Extracts., Brendan Mccarra

Theses

Spent dairy yeast Kluyveromyces marxianus (SDYK), a by-product of whey to ethanol fermentations, was investigated as a natural biomass source for the production of alternative flavoured yeast extracts. SDYK which was characterised by a high protein content (55.3% (w/w) ± 0.8) and comparable levels of flavor enhancing amino acids to that of S. cerevisiae was prepared for induced autolysis at different pH values in the presence of inductors sodium chloride and the proteolytic enzyme papain. An induced autolysis process was developed for the production of flavoured yeast extracts in which pH and autolytic treatment applied were found to have a …

Antilisterial Characteristics Of Volatile Essential Oils, Leeann L. Slaughter

Theses and Dissertations--Animal and Food Sciences

This study explored the in vitro and in situ antilisterial inhibitory activity of 16 essential oils during indirect exposure: Spanish Basil oil (Ocimum basilicum), Bay oil (Pimenta racemosa), Italian Bergamot oil (Citrus bergamia), Roman Chamomile oil (Anthemis nobilis), Sir Lanka Cinnamon oil (Cinnamomum zeylanicum), Citral, Clove Bud oil (Syzygium aromaticum), Cumin Seed oil (cuminum cyminum), Eucalyptus oil (Eucalyptus globulus), Eugenol, Geranium extract (Pelargonium graveolens), Marjoram oil (Origanum majorana), Neroli extract (Citrus aurantium), Peppermint oil (Mentha piperita L.), …

The Effect Of Non-Thermal Processing Technologies On Microbial Inactivation: An Investigation Into Sub-Lethal Injury Of Escherichia Coli And Pseudomonas Fluorescens, Rachel Halpin, L. Duffy, O. Cregenzán-Alberti,, J.G Lyng, F. Noci

Articles

In recent years, there has been an increased interest in food processing technologies that could lessen the thermal impact on food products. In the present study, thermosonication (TS) and pulsed electric fields (PEF), applied individually or in combination (TS/PEF), were investigated to determine their effects on inactivation and sub-lethal injury of Pseudomonas fluorescens and Escherichia coli. TS was applied at a low (L) and high (H) wave amplitude (18.6 μm and 27.9 μm, respectively), while PEF was applied at a low and high electrical field strength (29 kV cm⁻¹ and 32 kV cm⁻¹, respectively). In addition, …

Cloning, Expression, And Characterization Of Ara H 3, A Major Peanut Allergen, Cathryn E. Garvey

LSU New Orleans Theses and Dissertations

Abstract There are eight foods that contribute to food allergies in the western world and peanut is the most common. Currently, there are no medical treatments that can cure an individual of food allergy, so avoidance of the allergic food is the only option. In the United States, there are three immunodominant allergic proteins accountable for patient sensitization to peanut, Arachis hypogea 1, 2, and 3 (Ara h 1, Ara h 2, Ara h 3). Therefore, research into why peanuts are more allergic than other foods that have homologous proteins is critical and may be obtained by studying the structural …

Evidence Of Transmission Of Escherichia Coli O157:H7 To The Tissues Or Phyllo-Plane Of Wheat, From Contaminated Soil, Seeds Or Water, Bismarck Antonio Martinez

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

Escherichia coli O157:H7 is a human pathogen that can cause a wide spectrum of disease symptoms, such as bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Escherichia coli O157:H7 illness are mainly associated with undercooked beef; however, in recent years outbreaks have been linked to fresh produce such as spinach, lettuce, and sprouts. In 2009, flour was implicated as a contamination source in the consumption of raw cookie dough resulting in 77 illness-cases. The objective of this research was to determine the possible route of transmission of E. coli O157:H7 into the phyllo-plane of wheat using contaminated seed, soil …

Analysis Of Microbial Diversity By Amplicon Pyrosequencing, Ryan Legge

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

Microorganisms numerically dominate terrestrial biodiversity, and play important biochemical and geochemical roles in the environments they inhabit. To understand structure and function of complex ecosystems, it is essential to identify primary drivers of microbial diversity and community structure. Historically, the study of microbial ecology was reductive, limited to microbes able to be cultured and enumerated. Microbes meeting this criterion were thought to comprise the dominating members of the environments they were isolated from, however, estimates suggesting up to 99% of the endogenous species are uncultivable with existing methodologies; a concept that reflects experimental failure, rather than a verifiable conclusion. Therefore …

The Trade And Welfare Impacts Of Australian Quarantine Policies: The Case Of Pigmeat, John C. Beghin, Mark Melatos

Department of Agricultural Economics: Faculty Publications

We analyze the trade and welfare impact of quarantine measures imposed by Australia on imports of pigmeat. In particular, we account for changes to Australia’s pigmeat quarantine policy over time, including those changes related to the recent resolution of a WTO dispute between Australia and the European Union. Using a random utility model and applying it to corner solutions in import decisions, tariff equivalents (by major trading partner) are estimated for the different pigmeat quarantine regimes implemented by Australia during the period 1988-2009. The welfare impact on consumers, producers, and foreign exporters is computed using a partial equilibrium model calibrated …

Evaluation Of Prebiotic Fibers And Pectin On Probiotic Strains And Effect Of Bacteriocin-Like Substance On The Survival Of Listeria Monocytogenes, Dolar Pak

Graduate Theses and Dissertations

Probiotics and prebiotics have been shown to provide beneficial effects on the host health and there are numerous research efforts being conducted on a variety of specific applications. However, most prebiotic carbohydrates are lower molecular weight oligosaccharides; and the health benefits of higher molecular weight pectins have not been fully evaluated. According to reviews, pectins are fermented in the large intestine due to the cooperative activities of colonic bacteria with complementary enzymatic activities. There are very few studies that demonstrate the fermentability of high methoxy pectin and low methoxy pectin by pure cultures of human isolates or probiotic bacteria. Thus, …

Lactic Acid Production Using Sweet Potato Processing Waste, Irene Pagana

Graduate Theses and Dissertations

Organic waste generated from industrial sweet potato canning is estimated to be 30% of incoming raw material. This waste contains carbohydrates (sugars and starch) that could be used as substrates for the production of useful compounds via fermentation (e.g. lactic acid), resulting in the production of value-added products. The goal of this research project is to produce a substrate from the sweet potato processing waste material that supports the growth of lactic acid bacteria, which results in the production of lactic acid. The sweet potato waste product was characterized, and found to contain 16.5% solids. The solids components were 18.5% …

The Effect Of Chlorine And Ozone In Controlling Microbes On Organically Grown Cilantro And Carrots, Adam Holtz

BioResource and Agricultural Engineering

This senior project investigates the relative efficacy of ozonated water and chlorinated water for the purpose of sanitizing freshly-harvested organic produce. The aim of this study was to assist the Cal Poly Organic Farm in deciding whether or not to invest in an ozone generator. The crops used for testing were grown organically in the same field. Carrots and cilantro were harvested and promptly treated with 5 ppm ozone solution or 25 ppm sodium hypochlorite solution. Carrots were sampled at 0, 7, and 14 days storage to determine microbial populations. Cilantro was similarly tested at 0, 6, and 12 days …

Sanitation Assessment Of Food Contact Surfaces And Lethality Of Moist Heat And A Disinfectant Against Listeria Strains Inoculated On Deli Slicer Components, Sabelo Muzikayise Masuku

Graduate Theses and Dissertations

The overall objectives of this study were to: evaluate the efficacy of different cleaning cloth types and cloth-disinfectant combinations in reducing food contact surface contamination to acceptable levels; determine the optimum moist heat and moist heat + sanitizer treatments that can significantly reduce the number of Listeria strains on deli slicer components; and investigate if the moist heat treatment used in this study induced the viable-but-non-culturable (VBNC) state in Listeria cells. The efficacy of wiping cloths was measured using ATP-bioluminescence and total plate count methods using four different wiping cloths and silver dihydrogen citrate sanitizer on food contact surfaces. The …

Effect Of Enzymatic Treatments On The Physiochemical Properties Of Different Corn Starches, Curtis Robert Luckett

Graduate Theses and Dissertations

Amylose readily reassociates to form films and crystalline structures that are resistant to digestion by amylolytic enzymes and known as resistant starch type III (RS3). This study investigated the RS3 formation and cereal coating properties from enzyme-modified corn starches with varying amylose contents, including Hylon VII (70% amylose), Hylon V (50% amylose), and common corn (25% amylose). For RS3 formation, corn starches were first gelatinized and then hydrolyzed using β-amylase to varying degrees. The resultant hydrolyzed starch was debranched with isoamylase and then exposed to 3 times of temperature cycling at 135/133/133°C for 30 min and 95°C for 24 hr …

Validation Of Thermal Processing To Control Salmonella Spp. And Clostridium Perfringens During Prime Rib Preparation From Intact And Non-Intact Meat, Maria A. Calle

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

Beef prime rib is a delicacy cooked at low temperatures for long period and extended hot holding prior to consumption. Due to the potential survival and outgrowth of foodborne pathogens, this process may pose a public health risk. Considering an increase in the availability of non-intact beef, the microbial safety of the preparation of prime rib from intact and mechanically tenderized beef was evaluated.

In the first study, lethality of the prime rib (from intact and non-intact, blade tenderized beef) cooking process to Salmonella spp. was evaluated. Boneless beef rib eye was surface inoculated with a five-strain cocktail of Salmonella …

Role Of Lactic Acid Bacteria As A Bio-Sanitizer To Prevent Attachment Of Listeria Monocytogenes On Deli Slicer Contact Surfaces, And The Influence Of Listeria Innocua On The Attachment Of L. Monocytogenes On Selected Materials Located In The Food-Processing Environment, Jean Baptiste Ndahetuye

Graduate Theses and Dissertations

Listeria monocytogenes an important foodborne pathogen that continues to be a serious problem for the food industry. This pathogen contaminates food primarily during post-harvest in the food-processing environment. Its ecology in the food-processing environment is not well understood but previous research has demonstrated the ability of L. monocytogenes to survive on food contact surfaces after cleaning and disinfection. The current study explored the attachment of three lactic acid bacteria (LAB) strains, Lactobacillus animalis , Lb. amylovorus and Pediococcus acidilactici , their combination in a cocktail, and their influence to prevent the attachment of L. monocytogenes at room temperature by examining …

Feed Supplementation With Natural Extracts Of Cranberry And Its Efficacy On Campylobacter Colonization In Poultry, Ann Woo-Ming

Graduate Theses and Dissertations

Campylobacter spp. has been identified as one of the leading causative agents of food borne diarrheal illness. Epidemiological evidence has shown that poultry is the main source for human infection. Poultry are asymptomatic carriers of Campylobacter within their gastrointestinal tract, with colonization levels reaching 106-108 cfu/g cecal content. Surveys of domestic poultry flocks have estimated that approximately 90% of flocks are positive for Campylobacter colonization. Risk assessment studies have determined that by reducing levels of Campylobacter colonization during rearing, incidences of human infection will be significantly reduced. Currently there are no consistently effective treatments to eliminate Campylobacter from poultry flocks. …