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Microbiology

2020

Articles 1 - 13 of 13

Full-Text Articles in Food Science

Micro-Physiological Models To Mimic Mucosal Barrier Complexity Of The Human Intestine In Vitro, Abhinav Sharma Dec 2020

Micro-Physiological Models To Mimic Mucosal Barrier Complexity Of The Human Intestine In Vitro, Abhinav Sharma

Doctoral Dissertations

The mucosal barrier in the intestine is vital to maintain selective absorption of nutrients while protecting internal tissues and maintaining symbiotic relationship with luminal microbiota. This bio-barrier consists of a cellular epithelial barrier and an acellular mucus barrier. Secreted mucus regulates barrier function via in situ biochemical and biophysical interaction with luminal content that continually evolves during digestion and absorption. Increasing evidence suggests that a mucus barrier is indispensable to maintain homeostasis in the gastrointestinal tract. However, the importance of mucus barrier is largely underrated for in vitro mucosal tissue modeling. The major gap is the lack of experimental material …

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An Impedimetric Aptasensing System For The Rapid Detection Of Salmonella Typhimurium, America Sotero Dec 2020

An Impedimetric Aptasensing System For The Rapid Detection Of Salmonella Typhimurium, America Sotero

Graduate Theses and Dissertations

Salmonella Typhimurium is a foodborne pathogen associated with raw and undercooked eggs, poultry, beef, fruits, and vegetables. In the United States, Salmonella is responsible for approximately 1.2 million illnesses, 23,000 hospitalizations, and 450 deaths annually. For many years, conventional detection methods such as culture-dependent and PCR-based methods have been the “golden standards” for the detection of this pathogen due to their high sensitivity and reliability. However, they still have some disadvantages such as long enrichment steps and high costs that need to be overcome. The development of a rapid and reliable method for the detection of S. Typhimurium is needed …

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Assessment Of Grain Safety In Developing Nations, Jose R. Mendoza Dec 2020

Assessment Of Grain Safety In Developing Nations, Jose R. Mendoza

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

Grains are the most widely consumed foods worldwide, with maize (Zea mays) being frequently consumed in developing countries where it feeds approximately 900 million people under the poverty line of 2 USD per day. While grain handling practices are acceptable in most developed nations, many developing nations still face challenges such as inadequate field management, drying, and storage. Faulty grain handling along with unavoidably humid climates result in recurrent fungal growth and spoilage, which compromises both the end-quality and safety of the harvest. This becomes particularly problematic where there is little awareness about health risks associated with poor …

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Molecular Identification And Characterization Of Viral Pathogens Infecting Sweet Cherry, Aaron J. Simkovich Oct 2020

Molecular Identification And Characterization Of Viral Pathogens Infecting Sweet Cherry, Aaron J. Simkovich

Electronic Thesis and Dissertation Repository

Stone fruits are a valuable crop grown worldwide, however pathogens such as viruses threaten fruit production by reducing tree health and fruit yield. In an orchard within the Niagara region of Ontario, symptoms typical of viral infection such as chlorosis and leaf deformation were seen on sweet cherry (Prunus avium L.) trees. Next generation sequencing was performed on symptomatic and asymptomatic leaves and four viruses were identified. On the tree displaying the most severe symptoms, Prune dwarf virus (PDV), was the only virus detected. A survey conducted during this work showed 42% of cherry trees on a single …

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Sensitivity Of Planktonic Cells Of Staphylococcus Aureus To Elevated Hydrostatic Pressure As Affected By Mild Heat, Carvacrol, Nisin, And Caprylic Acid, Jyothi George, Sadiye Aras, Md Niamul Kabir, Sabrina Wadood, Shahid Chowdhury, Aliyar Cyrus Fouladkhah Sep 2020

Sensitivity Of Planktonic Cells Of Staphylococcus Aureus To Elevated Hydrostatic Pressure As Affected By Mild Heat, Carvacrol, Nisin, And Caprylic Acid, Jyothi George, Sadiye Aras, Md Niamul Kabir, Sabrina Wadood, Shahid Chowdhury, Aliyar Cyrus Fouladkhah

Agricultural and Environmental Sciences Faculty Research

Current study investigated effects of elevated hydrostatic pressure exposure in the presence of mild heat and natural antimicrobials against Staphylococcus aureus. Hydrostatic pressure of 350 to 550 MPa with nisin (5000 IU/mL), carvacrol, or caprylic acid (0.5% v/v) were applied for the reduction in four-strain mixture of S. aureus in HEPES buffer at 4 and 40 °C for up to 7 min. Results were statistically analyzed by ANOVA and D-values were additionally calculated using best-fitted linear model. Prior to exposure to treatments at 4 °C, counts of the pathogen were 7.95 ± 0.4 log CFU/mL and were reduced (p < 0.05) to 6.44 ± 0.3 log CFU/mL after 7 min of treatment at 450 MPa. D-value associated with this treatment was 5.34 min (R2 …

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Dietary Oligosaccharides Modulate Bifidobacterial Production Of The Neurotransmitter Gamma-Aminobutyric Acid, Michelle Rozycki Sep 2020

Dietary Oligosaccharides Modulate Bifidobacterial Production Of The Neurotransmitter Gamma-Aminobutyric Acid, Michelle Rozycki

Masters Theses

Bifidobacteria are the predominant members of the infant gut, colonize adults to a lesser extent, and are recognized as beneficial microbes. Various bifidobacterial species produce ��-aminobutryic acid (GABA), the chief inhibitory neurotransmitter in the mammalian central nervous system. It is postulated that in order to produce GABA, the bifidobacterial genome must contain the gadB and gadC genes which encode a glutamate decarboxylase and a glutamate/GABA antiporter, respectively. Once exported by GadC, GABA is absorbed and transported systemically throughout the host. We hypothesize that specific dietary oligosaccharides will modulate bifidobacterial production of GABA due to varying intracellular concentrations of glutamate. To …

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Does Circularizing Source-Separated Food Waste Present A Risk To Our Food?, Astha Thakali May 2020

Does Circularizing Source-Separated Food Waste Present A Risk To Our Food?, Astha Thakali

Electronic Theses and Dissertations

About a third of the food produced annually is wasted. Food waste recycling can be a way to close the loop and attain a more sustainable food system, however, the system must be carefully monitored and managed to avoid the introduction and build-up of contaminants. To study the potential presence of contaminants in food waste, source-separated food waste was collected and screened for five classes of contaminants (physical contaminants, heavy metals, halogenated organic contaminants, pathogens, and antibiotic resistance genes) from two separate regulatory environments (voluntary vs mandated food separation). The regulatory environment did not affect the level of contamination, except …

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Research Tools And Their Uses For Determining The Thermal Inactivation Kinetics Of Salmonella In Low-Moisture Foods, Soon Kiat Lau Apr 2020

Research Tools And Their Uses For Determining The Thermal Inactivation Kinetics Of Salmonella In Low-Moisture Foods, Soon Kiat Lau

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

The reputation of low-moisture foods as safe foods has been crumbling over the past decade due to repeated involvement in foodborne illness outbreaks. Although various pasteurization technologies exist, a majority are thermal processes and have not been well-characterized for pasteurizing low-moisture foods. In addition, the nature of a low-moisture food matrix introduces various experimental complications that are not encountered in high-moisture foods. In this dissertation, the development, building instructions, and characterization of various open source tools for studying the inactivation kinetics of microorganisms in low-moisture foods are described. The first tool is the TDT Sandwich, a dry heating device for …

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Utilization Of Emulsion Chemistries For Delivery And Antiviral Application Of Carvacrol, Hao-Yuan Hsu Apr 2020

Utilization Of Emulsion Chemistries For Delivery And Antiviral Application Of Carvacrol, Hao-Yuan Hsu

Masters Theses

Human norovirus (HuNoVs) are the most common enteric pathogen around the world that cause ~50% of foodborne illness of disease outbreaks annually. HuNoVs are the member of the Caliciviridae family, which consist of small (38 nm), unenveloped, single stranded RNA (ssRNA) viruses. Norovirus are divided into 5 genogroup (GI, GII, GIII, GIV, GV, GVI and GVII). The GI, GII, and GIV cause human illness, in addition, GII.4 genotype cause the most human disease. Due to HuNoVs are difficult cultured in vitro, the cultivable HuNoVs surrogates have been widely studied. Recently, some studies have been conducted with HuNoVs surrogates, for …

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Effect Of Homofermentative Inoculant On Fermentation Characteristics And Nutritive Values Of Corn Silage, Nafeesa Qudsia Hanif, Iffat Tahira, Nighat Sultana, Mujahid Hasan Mar 2020

Effect Of Homofermentative Inoculant On Fermentation Characteristics And Nutritive Values Of Corn Silage, Nafeesa Qudsia Hanif, Iffat Tahira, Nighat Sultana, Mujahid Hasan

Journal of Bioresource Management

An in vitro study was planned to assess the effects of a homofermentative microbial inoculant on the fermentation parameters and nutritive value of corn silage. The inoculant was applied at concentrations of 5x104cfu/g of forage (T1), 1x105cfu/g of forage (T2) 1.5x105cfu/g of forage (T3) and a negative control group (T0) without bacterial inoculant in three replicates each. At day 3, 7, 45 and 90 of the experiment individual buckets were opened to characterize the material, quick acidification, dry matter recovery, and aerobic stability of silage respectively. The temperature of the trial samples was 32.75±1.92 …

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Assessing Growth And Methods Of Decontamination Of Listeria Monocytogenes In Brushes And Brines Used For Production Of Washed-Rind Cheese, Rosalind Grace Neale Jan 2020

Assessing Growth And Methods Of Decontamination Of Listeria Monocytogenes In Brushes And Brines Used For Production Of Washed-Rind Cheese, Rosalind Grace Neale

Graduate College Dissertations and Theses

Washed-rind, or smear-ripened, cheeses are considered high-risk for contamination with Listeria monocytogenes due to favorable growth conditions on the cheese rind and multiple points for contamination during post-production cheese care and aging. Foodborne illness outbreaks have implicated wash solutions and washing tools as potential vectors for transmission of L. monocytogenes. In order to evaluate the risk posed by the wash solutions and cheese brushes independently, a three-objective study was developed to investigate the growth potential of L. monocytogenes in cheese washing solutions (Objective I) and the transfer potential of L. monocytogenes between wash solution and cheese brush bristles of three …

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The Exploration Of Nanotoxicological Copper And Interspecific Saccharomyces Hybrids, Matthew Joseph Winans Phd Jan 2020

The Exploration Of Nanotoxicological Copper And Interspecific Saccharomyces Hybrids, Matthew Joseph Winans Phd

Graduate Theses, Dissertations, and Problem Reports

Nanotechnology takes advantage of cellular biology’s natural nanoscale operations by interacting with biomolecules differently than soluble or bulk materials, often altering normal cellular processes such as metabolism or growth. To gain a better understanding of how copper nanoparticles hybridized on cellulose fibers called carboxymethyl cellulose (CMC) affected growth of Saccharomyces cerevisiae, the mechanisms of toxicity were explored. Multiple methodologies covering genetics, proteomics, metallomics, and metabolomics were used during this investigation. The work that lead to this dissertation discovered that these cellulosic copper nanoparticles had a unique toxicity compared to copper. Further investigation suggested a possible ionic or molecular mimicry …

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A Natural Antimicrobial From Bacillus Subtilis As A Biosanitizer For Resilient Membrane Biofilms, Pratishtha Verma Jan 2020

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 …

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