Food Microbiology Commons^™

Assessing Stress Responses To Atmospheric Cold Plasma Exposure Using Escherichia Coli Knock Out Mutants, Lu Han, Daniela Boehm, Sonal Patil, Patrick J. Cullen, Paula Bourke

Articles

Aim: This study investigated the effect of Atmospheric cold plasma (ACP) exposure induced stress on microbial inactivation patterns and the regulation of genes involved in the microbial stress response in conjunction with key processing parameters of exposure time and post treatment storage time.

Methods and Results: Cell suspensions of Escherichia coli BW 25113 and its isogenic knock-out mutants in rpoS, soxR, soxS, oxyR and dnaK genes were treated with high voltage ACP in a sealed package for 1, 3 and 5 min followed by 0, 1 and 24 h post-treatment storage. ROS densities and colony formation were …

Comparison Of Real-Time Pcr And Elisa-Based Methods For The Detection Of Beef And Pork In Processed Meat Products, Adam T. Perestam, Kayleigh K. Fujisaki, Omar Nava, Rosalee S. Hellberg

Food Science Faculty Articles and Research

Two commonly used methodologies for species detection within processed meat products are real-time polymerase chain reaction (PCR), a DNA-based method, and enzyme-linked immunosorbent assay (ELISA), a protein-based method. In this study, a real-time PCR assay was compared to a commercial ELISA kit based on sensitivity, specificity, agreement among duplicate samples, cost, time, and ease of use. Fifteen reference samples containing known percentages (0.1–99.9%, w/w) of pork and beef were analyzed in duplicate using both methods. Thirty commercial products, including sausages, pet treats, and canned meats, were also tested in duplicate with each method. Reference sample analysis showed real-time PCR was …

From Milpas To The Market: A Study On The Use Of Metal Silos For Safer And Better Storage Of Guatemalan Maize, José Rodrigo Mendoza

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

This project aimed to implement the use of metal silos to improve quality and safety of maize consumed by inhabitants of the highlands of Guatemala. This manuscript includes a literature review of the maize production chain in Guatemala, a survey about agricultural practices used in the region of study, as well as a characterization of the analyzed maize regarding its mycoflora, nutritional composition, and insect infestation. To better understand the current situation regarding agricultural practices and maize consumption, a survey was carried out. Sample consisted of 280 families representing 14 rural communities distributed in the townships of Todos Santos and …

Exploration Of Chemical And Biological Management Strategies For Diaphorina Citri The Primary Vector Of Candidatus Liberibacter Asiaticus, Gretta Marie Sharp

Biology Theses

Diaphorina citri (Hemipteran: Psyllidae), the Asian citrus psyllid, is a phloem-feeding, invasive species endemic to southern Asia that was first identified in the United States in Florida in 1998. Since introduction, D. citri has spread across the major citrus growing regions of the United States. This is of great concern to the citrus industry because D. citri is the primary vector of Candidatus Liberibacter asiaticus the causal agent of Haunglongbing (HLB). Haunglongbing is the most economically devastating disease of citrus causing an estimated 8.92 billion dollars lost in revenue and 4.62 billion dollars lost in gross domestic product between 2006-2007 …

The Use Of Lactic Acid Bacteria To Control The Growth Of Foodborne Pathogens On Fresh-Cut Fruits And Sprout Vegetables, Franca Gabriela Rossi

Master's Theses

Growing consumer awareness of the health benefits associated with fruits and vegetables and demand for easy to prepare products has prompted the development of a wide variety of minimally processed fruits and vegetables. Minimally processed fruits and vegetables are often peeled, cut, or diced which compromise the produces’ natural protective barriers, exposing a nutrient rich medium and providing an ideal environment for the growth of microorganisms, including foodborne pathogens. The germination conditions of sprout vegetables consisting of relatively high temperatures and humidity, low light and abundance of nutrients are also conducive to the proliferation of foodborne pathogens. Recent outbreaks and …

A Molecular Approach To Understanding The Effects Of Original-Xpc On The Modulation Of The Cecal Microbiota And The Survival Of Salmonella In The Poultry Host, Stephanie Roto

Graduate Theses and Dissertations

Salmonella is a foodborne pathogen commonly associated with poultry products; the economic burden to the U.S. is estimated to be approximately $693 million (without factoring in contaminated eggs). Recently, there has been pressure to withdraw sub-therapeutic levels of antibiotics (also known as antibiotic growth promoters; AGP) from poultry due to concern over antibiotic-resistant bacteria spreading to the human population. Therefore, various feed additives have been researched for their ability in providing protection against harmful pathogens and their potential growth promoting effects, both of which were attributes of poultry treated with AGP. This thesis consists of a comprehensive literature review that …

Comparative Efficacy Of Foaming And Non-Foaming Handsoap In Reduction Of Microorganisms In Handwashing, Danielle Marie Conover

Graduate Theses and Dissertations

Handwashing (HW) is a long established method to prevent disease transmission. Ensuring effectiveness of current HW methods is essential for optimal HW and enhanced disease prevention. The objectives of this research were to 1) conduct a survey of soap type and volume in food service establishments in Washington County, Arkansas; 2) investigate how soap type impacts HW behavior; and 3) determine the difference in microbial reduction between foaming (F) and liquid (L) handsoap. For Objective 1, food service establishments in Washington County, AR were selected based on exclusion criteria and random number generations, and handsoap samples were collected to determine …

A Novel And Rapid Staphylococcus Aureus Bacterial Identification Method Utilizing Immunomagnetic Beads And Single Cell Laser-Light Scattering, Kaylagh Hollen

All NMU Master's Theses

Staphylococcus aureus is the most commonly isolated human associated bacterial pathogen. It plays an important role in skin and soft-tissue infections, pneumonia, endocarditis, osteomyelitis, foreign-body infections, and sepsis. S. aureus diagnosis and treatment requires a minimum of 24-48. With this in mind, previous studies suggest that faster pathogen identification has been linked to improved patient outcomes. Improved patient outcomes including a reduction in hospitalization time, decreased risk of nosocomial infections, and decreased in medical costs. The impact of faster identification on patient outcome has led us to develop an alternative method of S. aureus identification via ImmunoMagnetic Separation (IMS) and …

The Effect Of Salt Reduction On The Microbial Composition And Quality Characteristics Of Sliced Roast Beef And Turkey, Chad Gary Bower

Department of Animal Science: Dissertations, Theses, and Student Research

This study analyzed the effects of salt reduction on microbiological composition and quality characteristics of deli-style turkey breast and roast beef. Turkey breast and roast beef were manufactured with four different salt concentrations: 1.0%, 1.5%, 2.0%, and 2.5% on a meat block basis in addition to sugar, phosphate, and water. Samples were cooked, chilled overnight, sliced, and packaged. On the day of slicing, samples were evaluated for water activity, cooking yield, proximate composition and percent salt. Samples were evaluated throughout 18w of refrigerated storage for pH, texture profile analysis, aerobic plate count (APC), and anaerobic plate count. Bacterial communities were …

Assessment Of Microbial And Growth Response Of Broilers Fed A Commercial Prebiotic, Sang In Lee

Graduate Theses and Dissertations

Prebiotic refers to nondigestible food ingredients that enhance the health of the host by selectively promoting one or more number of beneficial bacteria. Gibson and Roberfroid (1995) initially described prebiotics as compounds that neither hydrolyzed nor absorbed in upper part of the gastrointestinal tract, selectively stimulates growth of beneficial bacteria, enhance health of the host and able to amend microorganism population to healthier states. Prebiotics are particularly attractive supplements in animal production due to their variety of effects including production of short chain fatty acids, pH amendments and suppression of pathogen colonization. In addition, prebiotics were emphasized as antibiotic alternatives …

Synbiotic Ice Cream As A Probiotic Carrier Tested In A Human Blind Crossover Trial, Erin M. Mcnamara

Department of Nutrition and Health Sciences: Dissertations, Theses, and Student Research

Diet is an important factor in gastrointestinal health. A synbiotic food option utilizing prebiotic and probiotic ingredients may be beneficial for improving gastrointestinal health. To conduct a human subject study of synbiotic ice cream containing prebiotic (inulin) and two strains of probiotics (Lactobacillus casei KE99 and Bifidobacterium bifidum) to determine its effectiveness as a carrier for a these ingredients and to identify any negative gastrointestinal side effects.

The study started with baseline data collection including a food frequency, a three day food recall, and one stool sample. The study was a 12 week crossover design with three weeks consuming …

Decay Of Macroalgae And Leaves And Their Relation To Detrital Food Webs, Megan E. Grandinetti

Masters Theses & Specialist Projects

This project addressed if decaying macroalgae and leaf detritus play a major role in the detrital pool of a 7th-order karst riverine system. Decay rates, macroinvertebrates colonization patterns, and change in δ13C values of Cladophora, Platanus occidentalis, and a mix of Acer negundo and A. saccharinum were tracked during summer and autumn months for portions of multiple years.

Packs of air-dried Cladophora, Acer, and P. occidentalis were placed in mesh bags and put in groups (n=4) in wire baskets. Seven baskets were submerged in riffle (0.5 m) and deeper run (2 m) habitats. Benthic organic matter was collected with each …

An Analysis Of Bacterial Contamination Of Chicken Eggs And Antimicrobial Resistance, Holly Spitzer

All College Thesis Program, 2016-2019

Chicken eggs are a major component of American diets, with an average yearly consumption of approximately 250 eggs per person (American Humane Society). While highly nutritious, eggs are also one of the leading causes of food poisoning and food borne illness in the United States. Eggs may become contaminated by a number of different types of bacteria during production, including Salmonella, a group of bacteria that, according to the CDC, causes more than 1.2 million cases of food borne illness in the United States every year. In an effort to decrease the frequency of bacterial contamination, many food producers …

Antibacterial Effects Of Peppermint, Mentha Piperita Essential Oil In Free-Form And In Nanoparticles On Pseudomonas Fluorescens, Car Reen Kok, Junsi Yang, Ozan Ciftci, Robert W. Hutkins

UCARE: Research Products

Mentha piperita, commonly known as peppermint originally came from Europe and the Middle East and its oil is commonly used in traditional medicine and aromatherapy. Like many other free essential oils (EO), peppermint oil is believed to possess antimicrobial properties.

However, the application of EO in food as an antimicrobial agent has yet to be established. This would require proper formulation of the EO for it to be viable in foods. This study aims to test the effects of both free Mentha piperita EO and Mentha piperita EO nanoparticles against Pseudomonas fluorescens and compare their inhibitory effects. We used nanoparticles …

Studies Of Debaryomyces Hansenii Killer Toxin And Its Effect On Pathogenic Bloodstream Candida Isolates, Rhaisa A. Crespo Ramírez

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

Candida species are normal commensal organisms found in the skin, mouth, and gastrointestinal and genitourinary tracts of humans. Candida albicans is a normal component of the gut flora, and the oral and genital cavities. However, this organism is an opportunistic pathogen and it is one of the most frequently isolated species from patients with nosocomial fungal infections. Candida infections have grown in recent years due to antimycotics resistance and the extensive use of antibiotics. This has pushed scientists to look for alternative therapeutic agents to treat fungal infections.

Yeasts can produce toxic proteins called “mycocins” or “killer toxins” that can …

Effect Of Reduced Sodium Cheese On The Growth Of Pathogenic Bacteria And Inactivation Of Listeria Innocua Using Supercritical Fluid Extraction With Co2, Suyapa Padilla Antunez

Master's Theses

Listeria monocytogenes continues to challenge the dairy industry in causing post-process contamination of cheeses. To reduce risk of contamination, it is crucial to understand the growth and survival of pathogenic bacteria in cheese products and to develop post-process mitigation strategies. This study evaluated the fate of pathogens in reduced and regular sodium Mozzarella cheese, and the potential of Supercritical Fluid Extraction with CO₂ (SFE) to reduce Listeria innocua on Mozzarella and Queso Fresco. The survival of L. monocytogenes, Salmonella, and E.coli O157:H7 (2-3 log CFU/g) in reduced sodium Mozzarella (1.62%), compared to regular sodium Mozzarella cheese (2.15%) …

Use Of The Mitochondrial Control Region As A Potential Dna Mini-Barcoding Target For The Identification Of Canned Tuna Species, Jacquelyn K. Mitchell, Rosalee S. Hellberg

Food Science Faculty Articles and Research

In this study, a DNA mini-barcoding methodology was developed for the differentiation of species commonly found in canned tuna. Primers were designed to target a 236-base pair (bp) fragment of the mitochondrial control region (CR) and a 179-bp fragment of the first internal transcribed spacer region (ITS1). Phylogenetic analysis revealed the ability to differentiate 13 tuna species on the basis of the CR mini-barcode, except in a few cases of species introgression. Supplementary use of ITS1 allowed for differentiation of introgressed Atlantic bluefin tuna (Thunnus thynnus) and albacore tuna (Thunnus alalunga), while differentiation of introgressed Atlantic …

Effect Of Green Tea On Interaction Of Lipid Oxidation Products With Sarcoplasmic And Myofibrillar Protein Homogenates Extracted From Bovine Top Round Muscle, Nahathai Stapornkul, Tatiana Prytkova, Lilian Were

Food Science Faculty Articles and Research

The interaction between lipid oxidation products and bovine sarcoplasmic (SP) and myofibrillar protein (MP) homogenates in the presence of green tea was investigated. To monitor the effect of green tea on lipid oxidation, aldehydes were measured while effect on protein was monitored via changes in myoglobin, thiols, and tryptophan fluorescence over nine days of refrigerated storage. The presence of SP and MP decreased free aldehydes in the buffers. The SP bound more aldehydes than MP. The tea compounds exhibited more favorable binding energies than aldehydes near histidine 64 close to the heme moiety of myoglobin. Addition of tea lowered tryptophan …

High Throughput Genomic Sequencing Of Bioaerosols In Broiler Chicken Production Facilities, Kate M. O’Brien, Michael S. Chimenti, Morgan Farnell, Tom Tabler, Thomas Bair, Joey Lynn Bray, Matthew W. Nonnenmann

Faculty Publications

Chronic inhalation exposure to agricultural dust promotes the development of chronic respiratory diseases among poultry workers. Poultry dust is composed of dander, chicken feed, litter bedding and microbes. However, the microbial composition and abundance has not been fully elucidated. Genomic DNA was extracted from settled dust and personal inhalable dust collected while performing litter sampling or mortality collection tasks. DNA libraries were sequenced using a paired-end sequencing-by-synthesis approach on an Illumina HiSeq 2500. Sequencing data showed that poultry dust is predominantly composed of bacteria (64–67%) with a small quantity of avian, human and feed DNA (< 2% of total reads). Staphylococcus sp. AL1, Salinicoccus carnicancri and Lactobacillus crispatus were the most abundant bacterial species in personal exposure samples of inhalable dust. Settled dust had a moderate relative abundance of these species as well as Staphylococcus lentus and Lactobacillus salivarius. There was a statistical difference between the microbial composition of aerosolized and settled dust. Unlike settled dust composition, aerosolized dust composition had little variance between samples. These data provide an extensive analysis of the microbial composition and relative abundance in personal inhalable poultry dust and settled poultry dust.

Acoustic Emission Of Lactococcus Lactis Ssp. Lactis C2 Infected With Three Bacteriophages C2, Sk1 And Ml3, Luxi Meng

Theses and Dissertations--Animal and Food Sciences

The objective of this research was to monitor the Acoustic Emission (AE) produced by Lactococcus lactis ssp. lactis C2 infected with three bacteriophages (c2, sk1 and ml3 at 90 min) using an acoustic emission-monitoring device which was designed at University of Kentucky in Lexington KY. The acoustic emission data was collected and then analyzed. These Acoustic Emission (AE) data suggested that bacteriophage ml3, sk1 and c2 can easily be distinguished by the differences in Absolute Energy (ABE), Centroid Frequency (CF) and Peak Frequency (PF) signals. The AE data suggested that bacteriophage sk1 and c2 caused greater stress on the lactis …

Aptameric Sensors: In Vitro Selection Of Dna That Binds Bromocresol Purple, Derek B. Miller

Honors Undergraduate Theses

Aptamers being used as sensors is an emerging field that has capabilities of being tomorrow’s diagnostic tools. As aptameric sensors have become more popular, their visualization systems have been limited. The majority of today’s aptameric sensors require expensive machinery such as a fluorometer in order to visualize results. We propose a system that will cut the need for instrumentation and be detected via the naked eye. With the selection of an aptamer to bind the pH indicating dye bromocresol purple (BCP) this may be achieved. When rendered active, the binding towards BCP will facilitate a color change from yellow to …

Unraveling The Dose-Response Puzzle Of L. Monocytogenes: A Mechanistic Approach, S. M.Ashrafur Rahman, Daniel Munther, Aamir Fazil, Ben Smith, Jianhong Wu

Mathematics and Statistics Faculty Publications

Food-borne disease outbreaks caused by Listeria monocytogenes continue to impose heavy burdens on public health in North America and globally. To explore the threat L. monocytogenes presents to the elderly, pregnant woman and immuno-compromised individuals, many studies have focused on in-host infection mechanisms and risk evaluation in terms of dose-response outcomes. However, the connection of these two foci has received little attention, leaving risk prediction with an insufficient mechanistic basis. Consequently, there is a critical need to quantifiably link in-host infection pathways with the dose-response paradigm. To better understand these relationships, we propose a new mathematical model to describe the …

Effect Of Phytosanitary Irradiation And Methyl Bromide Fumigation On The Physical, Sensory, And Microbiological Quality Of Blueberries And Sweet Cherries, Karen Thang, Kimberly Au, Cyril Rakovski, Anuradha Prakash

Food Science Faculty Articles and Research

Background

The objective of this study was to determine whether irradiation could serve as a suitable phytosanitary treatment alternative to methyl bromide (MB) fumigation for blueberries and sweet cherry and also to determine the effect of phytosanitary irradiation treatment on survival of Salmonella spp. and Listeria monocytogenes on these fruit. ‘Bluecrop’ blueberries (Vaccinium corymbosum) and ‘Sweetheart’ cherries (Prunus avium) were irradiated at 0.4 kGy or fumigated with methyl bromide and evaluated for quality attributes during storage.

Results

Irradiation caused an immediate decrease in firmness of both fruit without further significant change during storage. Fumigated fruit, in …

Prebiotics And Synbiotics: Dietary Strategies For Improving Gut Health, Janina A. Krumbeck, Maria X. Maldonado-Gomez, Amanda E. Ramer-Tait, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

Purpose of review — A wide range of dietary carbohydrates, including prebiotic food ingredients, fermentable fibers, and milk oligosaccharides, are able to produce significant changes in the intestinal microbiota. These shifts in the microbial community are often characterized by increased levels of bifidobacteria and lactobacilli. More recent studies have revealed that species of Faecalibacterium, Akkermansia, and other less well studied members may also be enriched. We review the implications of these recent studies on future design of prebiotics and synbiotics to promote gastrointestinal health.

Recent findings — Investigations assessing the clinical outcomes associated with dietary modification of the …

Microbiological Control And Mechanisms Of Action Of High Voltage Atmospheric Cold Plasma, Lu Han

Doctoral

Dielectric barrier discharge-atmospheric cold plasma (DBD-ACP) is a promising non-thermal technology effective against a wide range of microorganisms. These studies were performed using a custom built DBD-ACP system. The inactivation efficacy was found to be governed by a series of critical control parameters, including treatment time, mode of exposure (Direct/Indirect exposure), applied voltage, applied gas content but was also very dependent on the characteristics of treatment targets. In this study, these parameters were investigated using in-package design along with a post-treatment storage procedure to align with industrial processing times as well as mitigation of post-process contamination. A range of food …

Controlling Microbial Safety Challenges Of Meat Using High Voltage Atmospheric Cold Plasma, Lu Han, Dana Ziuzina, Caitlin Marie Heslin, Daniela Boehm, Apurva Patange, David Millan-Sango, Vasilis Valdramidis, Patrick J. Cullen, Paula Bourke

Articles

Atmospheric cold plasma (ACP) is a non-thermal technology, effective against a wide range of pathogenic microorganisms. Inactivation efficacy results from plasma generated reactive species. These may interact with any organic components in a test matrix including the target microorganism, thus food components may exert a protective effect against the antimicrobial mode of action. The effect of an in-package high voltage ACP process applied in conjunction with common meat processing MAP gas compositions as well as bacteria type and meat model media composition have been investigated to determine the applicability of this technology for decontamination of safety challenges associated with meat …

Proteomics Study Of Pre-Harvest Sprouting In Wheat, Pramod Khadka

Electronic Theses and Dissertations

Pre-harvest sprouting (PHS) of wheat (Triticum aestivum L.) is a condition characterized by the early germination of spikes during moist environmental conditions. PHS lowers yield, degrades the quality of grain and thus limits the profits of wheat producers groups. During this investigation, proteomics studies of PHS-resistant and PHS-susceptible wheat embryos were conducted at different imbibition time periods via a cutting-edge technology called iTRAQ. Proteomic analysis revealed that 190 differentially expressed proteins might be involved in various cellular functions, such as carbohydrate metabolism, nitrogen metabolism, stress response, redox regulation, ATP synthesis, and protein translation, during this untimely germination of the wheat …

Comparative Study Of The D-Values Of Salmonella Spp. And Enterococcus Faecium In Wheat Flour, Didier Dodier

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

Low-moisture foods contaminated with Salmonella spp. have been implicated in several foodborne illness outbreaks in the United States. The food industry has to incorporate preventive control in their process and validate thermal processes to assure food safety. The thermal destruction of Enterococcus faecium ATTC 8459 and Salmonella spp. was determined at 3 water activity levels (0.11, 0.18 and 0.33) at 80ºC, 85ºC and 90ºC. Aerobic plates counts petrifilms were used as non-selective medium for both bacteria, Enterobacteriaceae petrifilms were used as selective medium for Salmonella spp., and peptone water modified with sodium azide as a selective medium for Enterococcus faecium …

Inactivation Of Escherichia Coli O157:H7 And Shiga Toxin Producing E. Coli (Stec) Throughout Beef Summer Sausage Production And The Use Of High Pressure Processing As An Alternative Intervention To Thermal Processing, Eric L. Oliver

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

Escherichia coli O157:H7 and six additional serogroups of Shiga Toxin-producing E. coli (STEC-7) have been implicated in foodborne illness outbreaks related to fermented sausage products and are considered adulterants by the USDA-FSIS. The objective of this study was to evaluate high pressure processing (HPP) as an alternative to thermal treatment to reduce STEC-7 meeting the USDA-FSIS performance standards (5.0-log reduction). A rifampicin-resistant, non-pathogenic E. coli (surrogate) cocktail, was used in manufacturing testing. Sausages were fermented at ~42.2°C, slowly increased to 54.4°C internal temperature, cold showered, and chilled for 6 hours. Sampling occurred post-fermentation (PF; pH 5.0), internal temperature 48.9°C (I-48.9°C), …

Efficacy Of Galactooliosaccharide (Gos) And/Or Rhamnose-Based Synbiotics In Enhancing Ecological Performance Of Lactobacillus Reuteri In The Human Gut And Characterization Of Its Gos Metabolic System, Monchaya Rattanaprasert

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

Probiotic L. reuteri has potential to produce antimicrobial compounds and secrete immunosuppressive factors. These metabolic attributes could benefit the human host by providing colonization resistance (competitive and metabolic exclusion) against enteropathogens and mitigating inflammation. As metabolically active cells are fundamental to such probiotic properties, synbiotic approaches that supply L. reuteri with a source(s) of carbon, energy, and/or external electron acceptor for cell growth in the gut environment could therefore prompt the probiotic to engage in beneficial activities. In this study, the efficacy of GOS and/or rhamnose-based synbiotic approaches in promoting colonization persistence and metabolic activity of L. reuteri was evaluated. …