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Food Microbiology

2020

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Full-Text Articles in Food Science

Effects Of Tempeh Fermentation On Soy Free And Bound Phenolics: Release, Transformation, And Stimulated Production, Amadeus Driando Ahnan Dec 2020

Effects Of Tempeh Fermentation On Soy Free And Bound Phenolics: Release, Transformation, And Stimulated Production, Amadeus Driando Ahnan

Doctoral Dissertations

The fermentation of tempeh, a traditional source of protein originated in Indonesia, has been reported to enhance the health-promoting potentials of various grains, legumes, and beans. Tempeh fermentation on soybeans can modulate the bioavailability of phenolic compounds, particularly isoflavones, bioactive compounds that have been found to be protective against lung, prostrate, and colon cancers. However, the mechanism of the protective benefits was unknown. Using whole-food and in vitro models, this study addressed this research gap by investigating the effects of tempeh fermentation using various cultures on the compositions of soy free, bound, and minor phenolics, as well as their antioxidative, …


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 …


Non-Sterile Fermentation Of Food Waste Using Thermophilic And Alkaliphilic Bacillus Licheniformis Ynp5-Tsu For 2,3-Butanediol Production, Joshua A. O'Hair, Qing Jin, Dajun Yu, Jian Wu, Hengjian Wang, Suping Zhou, Haibo Huang Dec 2020

Non-Sterile Fermentation Of Food Waste Using Thermophilic And Alkaliphilic Bacillus Licheniformis Ynp5-Tsu For 2,3-Butanediol Production, Joshua A. O'Hair, Qing Jin, Dajun Yu, Jian Wu, Hengjian Wang, Suping Zhou, Haibo Huang

Agricultural and Environmental Sciences Faculty Research

Conversion of food waste into 2,3-butanediol (2,3-BDO) via microbial fermentation provides a promising way to reduce waste disposal to landfills and produce sustainable chemicals. However, sterilization of food waste, an energy- and capital-costly process, is generally required before fermentation to avoid any contamination, which reduces the energy net output and economic feasibility of food waste fermentation. In this study, we investigated the non-sterile fermentation of food waste to produce 2,3-BDO using a newly isolated thermophilic and alkaliphilic B. licheniformis YNP5-TSU. Three unitary food waste samples (i.e., pepper, pineapple, cabbage wastes) and one miscellaneous food waste mixture were respectively inoculated with …


Evaluation Of Listeria Innocua Transfer From Personal Protective Equipment (Ppe) To The Plant Environment And Effective Sanitation Procedures To Control It In Dairy Processing Facilities, Karen Nieto Dec 2020

Evaluation Of Listeria Innocua Transfer From Personal Protective Equipment (Ppe) To The Plant Environment And Effective Sanitation Procedures To Control It In Dairy Processing Facilities, Karen Nieto

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

Listeria monocytogenes can survive and grow under wet environmental conditions encountered in dairy facilities. Pasteurization of milk kills L. monocytogenes; however, recent listeriosis outbreaks have linked post-pasteurization contamination from the food environment to the final product. One of the sources of microbial contamination may include employees and their personal protective equipment (PPE), which often become in contact with equipment and food contact surfaces. To understand this issue, this study evaluates Listeria innocua, as a surrogate for Listeria monocytogenes, transfer from PPE to food products and surfaces encountered in dairy plants. Gloves, aprons, and boots were inoculated with L. …


Observed Defects Of Swiss Cheese Based On The Microbiome Contribution To The Production Of Organic Acids, Vannessa D. Campfield Dec 2020

Observed Defects Of Swiss Cheese Based On The Microbiome Contribution To The Production Of Organic Acids, Vannessa D. Campfield

Boise State University Theses and Dissertations

The United States Department of Agriculture downgrades on the order of 17% of all Swiss cheese produced in the United States due to defects. Many of these defects are related to improper eye formation, number, distribution, or size; leading to an industry loss of over $69 million per annum. The microbiome in Swiss-type cheeses plays a significant role in eye development due to production of organic acids and gaseous emissions contingent on bacterial abundance and phenotype. The relationship between bacteria and the organic acids they produce leading to Swiss cheese defects can be correlated using Next-generation sequencing and high-performance liquid …


Development Of Novel Pectinase And Xylanase Juice Clarification Enzymes Via A Combined Biorefinery And Immobilization Approach, Shady Hassan Dec 2020

Development Of Novel Pectinase And Xylanase Juice Clarification Enzymes Via A Combined Biorefinery And Immobilization Approach, Shady Hassan

Doctoral

Hydrolytic enzymes, such as pectinase and xylanase, maybe harnessed for numerous industrial applications in food industry. Therefore, economic factors such as achievement of optimum yieldsandoverall production costs, in addition to biocatalyst instability,are the main obstacles tothe industrial production and exploitation of a enzymes. For example, microbially-derived enzymes are typically produced in fermenters using expensive growth media, which may account for 30 to 40% of the production cost, and such expense may be compounded further by downstream processing operations.To counter such disadvantages, the major trend in industrial utilization of enzymes in cost-sensitive processes has been to immobilize such biocatalysts on a …


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 …


The Use Of Inorganic And Organic Acids As Short Duration Antimicrobial Dips On Mitigating Pathogens Present On Commercial Chicken During Peri-Harvest, Dana Kristen Dittoe Dec 2020

The Use Of Inorganic And Organic Acids As Short Duration Antimicrobial Dips On Mitigating Pathogens Present On Commercial Chicken During Peri-Harvest, Dana Kristen Dittoe

Graduate Theses and Dissertations

With poultry being the most consumed meat in the United States, poultry processors must provide consumers with safe, wholesome products. As a consequence, poultry processors are faced with the challenge of reducing the presence of foodborne pathogens such as Salmonella spp. and Campylobacter jejuni among raw poultry products. Though multi-hurdle approaches using antimicrobials are placed throughout processing to reduce these pathogens, Salmonella and C. jejuni still persist among raw poultry. Thus, it was the objective of the current dissertation to investigate various antimicrobials, organic and inorganic acids, as short duration dips and sprays as means to reduce common pathogens (Salmonella, …


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 …


An Agent-Based Simulator For The Gastrointestinal Pathway Of Listeria Monocytogenes, Ashrafur Rahman, Ali Asgary, Daniel Munther, Aamir Fazil, Ben A. Smith, Jianhong Wu Nov 2020

An Agent-Based Simulator For The Gastrointestinal Pathway Of Listeria Monocytogenes, Ashrafur Rahman, Ali Asgary, Daniel Munther, Aamir Fazil, Ben A. Smith, Jianhong Wu

Mathematics and Statistics Faculty Publications

We developed an agent-based gastric simulator for a human host to illustrate the within host survival mechanisms of Listeria monocytogenes. The simulator incorporates the gastric physiology and digestion processes that are critical for pathogen survival in the stomach. Mathematical formulations for the pH dynamics, stomach emptying time, and survival probability in the presence of gastric acid are integrated in the simulator to evaluate the portion of ingested bacteria that survives in the stomach and reaches the small intestine. The parameters are estimated using in vitro data relevant to the human stomach and L. monocytogenes. The simulator predicts that 5%–29% of …


Dynamic Between Biomass, Ph And Acid Lactic By Microorganisms In Fermentation Of Fresh Milk, Emmanuel Rodriguez, Aurelio Castillo, Paul A. Valle, Yolocuauhtli Salazar Nov 2020

Dynamic Between Biomass, Ph And Acid Lactic By Microorganisms In Fermentation Of Fresh Milk, Emmanuel Rodriguez, Aurelio Castillo, Paul A. Valle, Yolocuauhtli Salazar

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.


Chemical Effects Of Cold Atmospheric Plasma On Food Nutrients, Juan Manuel Pérez Andrés Nov 2020

Chemical Effects Of Cold Atmospheric Plasma On Food Nutrients, Juan Manuel Pérez Andrés

Doctoral

A range of nonthermal techniques have demonstrated process efficacy in ensuring food product safety, extension of shelf-life and in general a retention of key quality attributes. However, various physical, chemical and biochemical effects of nonthermal techniques on both macro and micronutrients are evident, leading to both desirable and undesirable changes in food products. It is important to outline the effects of non-thermal techniques on food chemistry and the associated degradation mechanisms with the treatment of foods. Oxidation is one of the key mechanisms responsible for undesirable effects induced by non-thermal techniques. Degradation of key macromolecules largely depends on the processing …


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 …


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 …


Development Of Essential Oil Incorporated Active Film Based On Biodegradable Blends Of Poly (Lactide)/Poly (Butylene Adipate‑Co‑Terephthalate) For Food Packaging Application, Shubham Sharma, Sandra Barkauskaite, Swarna Jaiswal, Brendan Duffy, Amit Jaiswal Aug 2020

Development Of Essential Oil Incorporated Active Film Based On Biodegradable Blends Of Poly (Lactide)/Poly (Butylene Adipate‑Co‑Terephthalate) For Food Packaging Application, Shubham Sharma, Sandra Barkauskaite, Swarna Jaiswal, Brendan Duffy, Amit Jaiswal

Articles

Active packaging improves food safety and quality with the incorporation of certain additives such as antimicrobial agents. The PLA/PBAT films were prepared with two essential oils—eucalyptus oil and cinnamon oil of various concentrations (1%, 5%, and 10% w/w) and characterized their optical and mechanical properties, surface hydrophobicity, chemical composition, and antimicrobial activity. Cinnamon oil composite films were observed as thicker films (88.88 µm) than the eucalyptus oil films (54.46 µm). The highest UV-blocking properties were observed in cinnamon oil films. However, transparency and tensile properties of the cinnamon oil films decreases as the concentration increases. The tensile strength of the …


Effects Of Salt And Garlic Concentration On The Microbial Safety, Biochemical Properties, And Sensory Acceptance Of Spontaneously Fermented Beet Kvass, Abigail Hing Aug 2020

Effects Of Salt And Garlic Concentration On The Microbial Safety, Biochemical Properties, And Sensory Acceptance Of Spontaneously Fermented Beet Kvass, Abigail Hing

Electronic Theses and Dissertations

Fermentation is the process by which primarily lactic acid bacteria (LAB), an environmentally ubiquitous group of organisms, convert carbohydrates into several byproducts, including acid, ethanol and/or gas. Often these resulting byproducts create desirable foods with unique flavor attributes and an increased inherent safety due to acidification. Vegetables such as red beetroot are suitable commodities for fermentation, due to abundant nutrient sources to sustain the LAB population. However, sufficient growth of LAB may lead to the production of harmful biogenic amines, specifically histamine and tyramine which can cause an allergic reaction and poisoning at high levels. Additionally, red beetroot is grown …


Characterization And Antimicrobial Activity Of Biodegradable Active Packaging Enriched With Clove And Thyme Essential Oil For Food Packaging Application, Shubham Sharma, Sandra Barkauskaite, Brendan Duffy, Amit Jaiswal, Swarna Jaiswal Aug 2020

Characterization And Antimicrobial Activity Of Biodegradable Active Packaging Enriched With Clove And Thyme Essential Oil For Food Packaging Application, Shubham Sharma, Sandra Barkauskaite, Brendan Duffy, Amit Jaiswal, Swarna Jaiswal

Articles

Bioactive packaging contains natural antimicrobial agents, which inhibit the growth of microorganisms and increase the food shelf life. Solvent casting method was used to prepare the Poly (lactide)-Poly (butylene adipate-co-terephthalate) (PLA-PBAT) film incorporated with the thyme oil and clove oil in various concentrations (1 wt%, 5 wt% and 10 wt%). The clove oil composite films depicted less green and more yellow as compared to thyme oil composite films. Clove oil composite film has shown an 80% increase in the UV blocking efficiency. The tensile strength (TS) of thyme oil and clove oil composite film decreases from 1.35 MPs (control film) …


Performance Of A Uv-A Led System For Degradation Of Aflatoxins B1 And M1 In Pure Water: Kinetics And Cytotoxicity Study, Judy Stanley, Ankit Patras, Brahmaiah Pendyala, Matthew J. Vergne, Rishipal R. Bansode Aug 2020

Performance Of A Uv-A Led System For Degradation Of Aflatoxins B1 And M1 In Pure Water: Kinetics And Cytotoxicity Study, Judy Stanley, Ankit Patras, Brahmaiah Pendyala, Matthew J. Vergne, Rishipal R. Bansode

Agricultural and Environmental Sciences Faculty Research

The efficacy of a UV-A light emitting diode system (LED) to reduce the concentrations of aflatoxin B1, aflatoxin M1 (AFB1, AFM1) in pure water was studied. This work investigates and reveals the kinetics and main mechanism(s) responsible for the destruction of aflatoxins in pure water and assesses the cytotoxicity in liver hepatocellular cells. Irradiation experiments were conducted using an LED system operating at 365 nm (monochromatic wave-length). Known concentrations of aflatoxins were spiked in water and irradiated at UV-A doses ranging from 0 to 1,200 mJ/cm2. The concentration of AFB1 and AFM1 was determined by HPLC with fluorescence detection. LC–MS/MS …


Enteric Biopolymer Composite Coatings To Enhance The Viability Of Powdered Probiotics During Preparation, Storage, And Simulated Digestions, Anyi Wang Aug 2020

Enteric Biopolymer Composite Coatings To Enhance The Viability Of Powdered Probiotics During Preparation, Storage, And Simulated Digestions, Anyi Wang

Doctoral Dissertations

Due to suppressed metabolisms, powdered probiotics are generally more stable and more convenient for applications than the liquid form, but much work is needed to improve viability of powdered probiotics during processing, storage, and digestions. The goal of this dissertation was to fabricate delivery systems with an enteric biopolymer coating and a core of powdered probiotic ingredients. The principle of preparing powdered probiotics was to directly mix a concentrated cell suspension with hygroscopic food ingredient powders. Amorphous spray-dried lactose (SDL) was first studied to prepared powdered Lactobacillus salivarius NRRL B-30514 in chapter 2. A smaller amount of cell suspension resulted …


Microemulsions Of Cinnamon And Orange Oils As An Antimicrobial Delivery System For Salmonella Biofilms On Stainless Steel, Jennifer Vuia-Riser Aug 2020

Microemulsions Of Cinnamon And Orange Oils As An Antimicrobial Delivery System For Salmonella Biofilms On Stainless Steel, Jennifer Vuia-Riser

Doctoral Dissertations

Essential oils (EOs) are natural antimicrobials that can be used to develop intervention strategies to inhibit pathogens, but EOs are lipophilic. Colloidal systems, such as microemulsions, are needed for food industry applications. This dissertation focused on the development and characterization of a microemulsion composed of cinnamon oil (CO, Cinnamomum zeylanicum) and orange oil (OO, Citrus sinensis) to be used against Salmonella Enteritidis H4267 biofilms formed on stainless steel disc surfaces.

First, the antimicrobial activity of CO and OO against S. Enteritidis H4267, either used in combination or in a microemulsion system, was determined. CO had a greater antimicrobial …


Exploring The Connection Between Acid Exposure And Virulence In Listeria Monocytogenes, Minghao Li Aug 2020

Exploring The Connection Between Acid Exposure And Virulence In Listeria Monocytogenes, Minghao Li

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Listeria monocytogenes is a gram-positive food-borne pathogen that is widely dispersed in the environment and can cause listeriosis with high fatality rates when consumed in contaminated food products. They are capable of growing over a wide range condition. Listeria is also able to tolerate adverse conditions which allows the bacterium to survive in unfavorable environments. The ubiquitous nature of L. monocytogenes makes it difficult to eliminate from food systems. One major problem in the food industry is the survival of L. monocytogenes under sublethal low pH-environment since organic acids are widely used as food decontaminants. Prior research has suggested that …


Effect Of Long Pasteurization Run Times On Bacterial Numbers In Milk, Brynli Tattersall Aug 2020

Effect Of Long Pasteurization Run Times On Bacterial Numbers In Milk, Brynli Tattersall

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This project was funded by the Western Dairy Center to understand how long a milk pasteurizer can be operated before increases in bacterial numbers are observed in the pasteurized milk. While pasteurization kills pathogenic bacteria there are some non-pathogenic bacteria that can survive and have the ability to become attached to the surfaces in the cooling sections of the pasteurizer. Some bacteria can also produce spores that survive pasteurization even if the bacterial cells are killed. Temperatures in the cooling section remain in a range suitable for growth of these heat-tolerant bacteria and can allow germination of bacterial spores. While …


Biogenic Amines As A Product Of The Metabolism Of Proteins In Beer, Hayden Koller Aug 2020

Biogenic Amines As A Product Of The Metabolism Of Proteins In Beer, Hayden Koller

Electronic Theses and Dissertations

For many years the only beer that was commercially available in the United States were simple lagers and ales made primarily of barley (and other cereals), water, hops, and yeast. These beer varieties were simple and quick to produce with high levels of consistency. In the last 30 years the rise in craft and microbreweries have dramatically changed the landscape of brewing and beer. As smaller breweries rose in popularity so did the use of unique ingredients such as vegetables, fruits, herbs, meat, etc. along with higher gravity mashes and long barrel aging times. All these ingredients have a profound …


Development Of Headspace Analysis Of Living And Postharvest Fresh Produce Using Surface-Enhanced Raman Spectroscopy (Sers), Xinyi Du Jul 2020

Development Of Headspace Analysis Of Living And Postharvest Fresh Produce Using Surface-Enhanced Raman Spectroscopy (Sers), Xinyi Du

Masters Theses

The increasing market demand for fresh produce promotes a keen interest in developing a rapid, sensitive and reliable method for monitoring plant health and determining the shelf-life of postharvest produce. The objective of this study is to explore the capability of Surface-enhanced Raman spectroscopy (SERS) in these applications. SERS integrates Raman spectroscopy which measures molecular vibrations and nanotechnology which enhances the weak Raman signals. Herein, we developed two SERS methods based on a surface detection approach using nanoparticles solution and a headspace detection approach using gold nanoparticles (AuNPs) fibers, to detect biochemical changes during postharvest storage of arugula leaves. Compared …


Evaluation And Impact Of Food Safety Messages In New Media For Trending Recipes: Savory Jam On Youtube, Alison L. Brodt Jul 2020

Evaluation And Impact Of Food Safety Messages In New Media For Trending Recipes: Savory Jam On Youtube, Alison L. Brodt

Electronic Theses and Dissertations

Home canning has been used as a method of food preservation for hundreds of years. The United States has a regulatory agency known as the National Center for Home Food Preservation (NCHFP), which gives guidelines on canning safely to decrease the risk of foodborne illness. The NCHFP provides tips for fruit jams and jellies; however, savory jam is rising in popularity. Savory jam includes jams with a savory main ingredient, such as tomatoes, bacon, onion, or chili peppers. There are currently no guidelines for safe preparation of savory jams. Research is needed to see if recipes for savory jam are …


Improving Microbiological Safety Of Low Moisture Food Products Using Radio Frequency And Ethylene Oxide, Long Chen Jun 2020

Improving Microbiological Safety Of Low Moisture Food Products Using Radio Frequency And Ethylene Oxide, Long Chen

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Recent foodborne illness outbreaks in US associated with consumption of low-moisture foods (LMF) have heightened concerns of their microbial safety. Salmonella is a pathogen of major concern in LMF due to its ability to persist in low water activity (aw) environments. The disadvantages of existing decontamination technologies for LMF call for novel and efficient intervention technologies. Radio frequency (RF) and ethylene oxide (EtO) were evaluated in this dissertation for improving microbial food safety and quality of LMF. Cumin seeds and inshell hazelnuts were selected as model foods.

It took < 2 min of stationary RF heating to achieve > 5 log reductions of Salmonella in cumin seeds without …


Authentication Of Red Snapper (Lutjanus Campechanus) Fillets Using A Combination Of Real-Time Pcr And Dna Barcoding, Rachel B. Isaacs, Rosalee S. Hellberg May 2020

Authentication Of Red Snapper (Lutjanus Campechanus) Fillets Using A Combination Of Real-Time Pcr And Dna Barcoding, Rachel B. Isaacs, Rosalee S. Hellberg

Food Science Faculty Articles and Research

Red snapper (Lutjanus campechanus) is a historically overfished and highly valued species that is commonly substituted with other fish, such as tilapia, rockfish, and other snapper species. The objective of this study was to assess the ability of real-time PCR to be used as a screening tool to rapidly test commercial fillets for the presence of red snapper, followed by species identification of negative samples with DNA barcoding. A total of 24 frozen, fresh, or thawed (previously frozen) fillets labeled as “red snapper” were tested with real-time PCR, along with 54 fillets from fish that are common substitutes …


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 …


Thermal Inactivation Of Bacterial Pathogens And Fungal Spores Under Post-Process Contamination Scenarios In Maple Syrup Processing, Maria Fiore May 2020

Thermal Inactivation Of Bacterial Pathogens And Fungal Spores Under Post-Process Contamination Scenarios In Maple Syrup Processing, Maria Fiore

Electronic Theses and Dissertations

Maple syrup is produced by the extensive thermal evaporation of maple sap traditionally collected from the Acer saccharum tree and other maple varietals. The resulting low water activity product (Aw < 0.85) is classified by the FDA as a low risk food commodity, due to the moisture limitations which inhibit the growth of pathogenic microorganisms. However, recent outbreaks associated with other designated low risk products, including peanut butter and wheat flour, now challenge the current understanding of factors required to induce human illness. Among the most notorious bacterial pathogens, as few as ten bacterial cells, have been cited to cause infection. In addition to bacteria-based risks, fungal contaminants have also been noted to jeopardize safety due to the potential for mycotoxin production, penetrating beyond the immediate product surface.

The extensive heating process required to produce syrup from sap is sufficient to eradicate the majority of present microflora. However, post-process contamination scenarios, which are augmented by producer behaviors, can introduce microorganisms into the finished product. Among these risk factors include direct product contamination due to insufficient heating temperatures, or contamination of bottles, as a result of improper container storage. Therefore, the objectives of this work are to (i) determine …


Elucidating Basis Of Rice Discoloration And Developing Prevention Strategies, Zeinab Mohammadi Shad May 2020

Elucidating Basis Of Rice Discoloration And Developing Prevention Strategies, Zeinab Mohammadi Shad

Graduate Theses and Dissertations

Economically, discolored rice kernels have less market value, which can seriously impact farm net profit. The reasons for rice discoloration during storage have not been studied extensively and many questions remain. Therefore, the primary goal of this study was to improve understanding of the role and contributions of storage practices on rice quality degradation and discoloration. In this study, three rice cultivars including XL753 (hybrid), Roy J (pureline), and Titan were assessed for changes in quality and microbial kinetics. The rice samples at a high moisture content (MC) of 21% w.b. and a low MC of 16% were stored at …