Food Microbiology Commons^™

Food Safety Risk In An Indoor Microgreen Cultivation System, Gina Marie Misra

Theses and Dissertations

Microgreens are immature sprouts of edible plants, sharing some similarities with sprouted seeds and petite leafy greens. Since they are most often grown in containers in buildings or greenhouses, they present a new area for food safety research at the intersection of the built environment and produce farming. Contamination by human pathogens has been extensively studied in other types of produce typically eaten raw, including sprouted seeds, which have been implicated in numerous outbreaks of salmonellosis over the last several decades. There is a paucity of knowledge about the microgreen sector of the fresh-cut industry; thus, it was determined that ...

Impact Of Selected Infrared Wavelengths Treatment On Inactivation Of Microbes On Rough Rice, Rebecca Bowie

Food Science Undergraduate Honors Theses

Formation of harmful microbes and their associated mycotoxins on rough rice during storage present negative socioeconomic impacts to producers and consumers. The objective for this study was to investigate the impact of treating rough rice with selected infrared (IR) wavelengths at different IR intensities and heating durations, followed by a tempering step for further inactivation of microbes (mold and bacteria) on the grain. Freshly-harvested long-grain, hybrid, rough rice (XL 745) with initial moisture content (IMC) of 18.4% wet basis (w.b.) was used. Two-hundred grams (200 g) of the samples were treated at different IR wavelengths (λ) which were ...

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 ...

Producer Willingness To Pay For Enhanced Packaging To Prevent Postharvest Decay Of Strawberries, Brian Coffey, Valentina Trinetta, Londa Nwadike, Umut Yucel

Journal of Applied Farm Economics

We surveyed specialty crop producers in Kansas and Missouri to determine producer willingness to pay for new active packaging technology that prevents postharvest loss and increases shelf life. The survey also asked demographic questions to determine the producer and operation traits for this growing segment of production agriculture. More than half of those surveyed were female, and 60% were under 50 years of age. Smaller operations tend to utilize direct marketing and social media activity more than larger operations. Parametric willingness to pay estimates are approximately $0.39 per cardboard flat to purchase the antifungal film that increases shelf life ...

Do Lactic Acid Bacteria In Fermented Foods Persist In The Gastrointestinal Tract: An In Vitro Investigation, Chloe M. Christensen, Car Reen Kok, Robert W. Hutkins

UCARE Research Products

It is now well established that the composition of the gastrointestinal (GI) microbiota has a profound influence on intestinal and overall health. Many contemporary diseases such as type two diabetes, IBS and obesity are associated with a dysbiotic microbiota. Therefore, researchers are interested in how diet and specific dietary components can modulate the gastrointestinal microbiota and possibly repair a dysbiotic state. One approach to improve gastrointestinal health is by consuming probiotics and prebiotics or a diet rich in fermented foods containing live microbes. Fermented foods are popular because of their enhanced preservation, safety, organoleptic, functionality, and nutritional properties. These fermented ...

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

Dissertations, Theses, & Student Research in Food Science and Technology

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 ...

Edible Films Made Of Corn Zein Protein And Cellulose Derivatives, Gloria Dukuzeyesu, Changmou Xu, Zhang Yue

UCARE Research Products

A composite edible film made of corn zein protein (Z) and cellulose derivatives (C) was successfully fabricated. Edible films are coatings used to wrap food products to protect them against microbial deterioration, loss of moisture, and to extend the shelf life of the product. These edible films are consumed together with the product . The mechanical properties, water vapor permeability, application on fruits, and shelf life of the composite film were studied. Zein demonstrated excellent packing characteristics; due to its high no polar contents and hydrophobic nature, zein film served as a moisture barrier. Hydroproxy methylcellulose (HPM) is tasteless, odorless and ...

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 ...

A Syringe-Based Biosensor To Rapidly Detect Low Levels Of Escherichia Coli (Ecor13) In Drinking Water Using Engineered Bacteriophages, Troy C. Hinkley, Spencer Garing, Paras Jain, John Williford, Anne-Laure M. Le Ny, Kevin P. Nichols, Joseph E. Peters, Joey N. Talbert, Sam R. Nugen

Food Science and Human Nutrition Publications

A sanitized drinking water supply is an unconditional requirement for public health and the overall prosperity of humanity. Potential microbial and chemical contaminants of drinking water have been identified by a joint effort between the World Health Organization (WHO) and the United Nations Children’s Fund (UNICEF), who together establish guidelines that define, in part, that the presence of Escherichia coli (E. coli) in drinking water is an indication of inadequate sanitation and a significant health risk. As E. coli is a nearly ubiquitous resident of mammalian gastrointestinal tracts, no detectable counts in 100 mL of drinking water is the ...

Growing Torula Yeast (Candida Utilis) For Food Grade Fatty Acids, Zachary Christman

Theses, Dissertations, and Student Research in Agronomy and Horticulture

The focus of this article is the cultivation of a food grade yeast for the production of fatty acids without the restrictions of climate or growing season. Torula yeast (Candida utilis) was selected since it can grow on a wide variety of culture media and has over 60 years of use in the food industry. The fatty acid composition of Candida utilis grown on two different media are presented in this article; the first example using completely synthetic media and another using distiller’s vinasse. Also, the effect of different culturing conditions on the percentage of various fatty acids will ...

Moisture Sorption Behavior And Shelf Life Prediction Of Teff Seed And Flour, Baba Abdissa, Rudrayya Math, Kodandaramreddy Desham, Srinivasulu Korra

Journal of Applied Packaging Research

Moisture sorption isotherms of Teff seed and its flour were determined over the range of relative humidity (11–92%) using a gravimetric technique at constant temperature (27°C). The results obtained showed that the moisture sorption isotherm of both is almost similar and sigmoid with increasing equilibrium water content at the constant temperature. The curves start raising high above 64% RH indicating the products deteriorates faster above 64% RH. Hence the moisture content equilibrating to 64% RH was taken as critical for both Teff seed and flour variants. The sorption isotherm fits the GAB equation as per GAB generalized equation ...

Marine Toxins Targeting Kv1 Channels: Pharmacological Tools And Therapeutic Scaffolds, Rocio K. Finol-Urdaneta, Aleksandra Belovanovic, Milica Micic-Vicovac, Gemma K. Kinsella, Jeffrey R. Mcarthur, Ahmed Al-Sabi

Articles

Toxins from marine animals provide molecular tools for the study of many ion channels, including mammalian voltage-gated potassium channels of the Kv1 family. Selectivity profiling and molecular investigation of these toxins have contributed to the development of novel drug leads with therapeutic potential for the treatment of ion channel-related diseases or channelopathies. Here, we review specific peptide and small-molecule marine toxins modulating Kv1 channels and thus cover recent findings of bioactives found in the venoms of marine Gastropod (cone snails), Cnidarian (sea anemones), and small compounds from cyanobacteria. Furthermore, we discuss pivotal advancements at exploiting the interaction of κM-conotoxin RIIIJ ...

Characterization And Use Of Pathogen Specific Bacteriophages To Reduce The Viability Of Escherichia Coli O157:H7 Contamination On Fresh Produce, Badrinath Vengarai Jagannathan

Theses and Dissertations--Animal and Food Sciences

Fresh produce is one of the most common sources of food-borne outbreaks, involving various pathogenic microorganisms such as Escherichia coli. Recent outbreaks have clearly shown that post-harvest washing has limited effectiveness on decontaminating produce and may contribute to cross-contamination of produce due to various limitations. Excessive use of sanitizers and antibiotics has also led to the development of many antibiotic-resistant strains of bacteria that have made the food industry more vulnerable.

Bacteriophages are a bacterial viruses that can selectively infect and replicate within bacteria leading to cell lyse and death. Bacteriophages have become widely recognized due to their ability to ...

The Parmesan Cheese Model System: Alleviation Of Browning Defect In Parmesan Cheese, Megan Huegli Aubrey

Electronic Theses and Dissertations

In cold temperature storage, Parmesan cheese can develop an undesirable browning defect. Certain pyrazine compounds converted from methylglyoxal have been identified and associated with the brown pigmentations in Parmesan cheese samples. This study focused on creating a cheese model system to study variables that caused browning and variables that helped reduce or alleviate browning. The cheese making steps for the cheese model system were monitored by measuring pH and TA and the final composition for % fat, % moisture, % salt and pH. Additionally, the cooling curve was studied to ensure all wheels of cheese made were cooled similarly. Cheese made in the ...

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 ...

Validation Of A Fluorescence-Based Bacteria Enumeration And Viability Determination Method Using Image Cytometry, Matthew R. Hodgkin

Electronic Theses and Dissertations

Craft beer production in the United States has been increasing significantly in recent years. As production and participation in the industry increases, so have consumer demands for more beer options. Breweries have met this call with experimentation of ingredients in their beer and also the styles they brew. One such beer, the sour beer, is an example of this experimentation and new product development. Sour beers are a style that differ from most other beers by how they are manufactured. Instead of being fermented with only yeast, both a lactic acid-producing bacteria and yeast are used. With increased competition amongst ...

The Anti-Campylobacter Activity And Mechanisms Of Pinocembrin Action, Anja Klančnik, Katarina Šimunović, Jasna Kovac, Orhan Sahin, Zuowei Wu, Darinka Vučković, Maja Abram, Qijing Zhang, Sonja Smole Možina

Veterinary Diagnostic and Production Animal Medicine Publications

We investigated the anti-Campylobacter activity of pinocembrin and its mechanism of action, as well as Campylobacter responses to pinocembrin treatment at the genetic and phenotypic levels, using C. jejuni NCTC 11168 and a multidrug efflux system repressor mutant (11168ΔcmeR). At its minimal inhibitory concentration, pinocembrin significantly increased cell membrane permeability of Campylobacter. Interestingly, at sub-inhibitory concentrations, pinocembrin did not significantly alter membrane functionality and it increased bacterial fitness. Treatment with pinocembrin evoked decreased expression of ribosomal proteins and down-regulation of several NADH dehydrogenase I chain subunits and proteins involved in iron uptake. This suggests altered protein production and redox cycle ...

The Physicochemical Properties Of Soy Protein Hydrolysate And Its Formulation And Stability With Encapsulated Probiotic, John Stricklin Edwards

Theses and Dissertations

Soy protein isolate (SPI) and probiotics can serve as a functional ingredient and beneficial supplement, respectively, to food formulations, but few studies focus on the compatibility of these two ingredients. The objective of this study was to prepare soy protein isolate (SPI) from defatted soybean flour and identify an optimal hydrolysis protocol to create soy protein hydrolysates (SPH) with improved solubility and functional properties and achieve an optimum encapsulation technique for probiotics and to determine the in vitro viability of encapsulated probiotic cells with SPH in a gastrointestinal environment. The SPI was prepared using an alkaline extraction procedure for solubility ...

Effect Of Storage Temperature On The Survival Or Growth Of Listeria Monocytogenes On Whole And Fresh-Cut Produce, Juan F. Moreira Calix

LSU Master's Theses

Whole and fresh-cut produce are minimally processed and, therefore susceptible to microbial contamination. This study examined the survival or growth of Listeria monocytogenes on whole, and fresh-cut produce at different storage temperatures. Fresh fruits (cantaloupes, pears, pineapples, papayas, and watermelon) and vegetables (broccoli, cauliflower, lettuce, kale, and green bell peppers) were cut into 25 g pieces and were spot inoculated with 0.5 mL (8 Log CFU/mL) of Listeria monocytogenes. Inoculated fresh-cut samples were stored at 4°C or 13°C for 6 days. To represent the outer surface of the produce, cantaloupes and green bell pepper disks (20 ...

Effect Of Processing On Microbiota Accessible Carbohydrates In Whole Grains, Caroline Smith

Dissertations, Theses, & Student Research in Food Science and Technology

There is potential to increase microbiota accessible carbohydrates (MAC) in whole grains through food processing. Therefore, different processing conditions for boiling and extrusion of whole wheat flour were studied for their effect on MAC. Processing conditions had a minimal effect on fermentation response using 2 fecal samples of disparate composition. However, the processing method had an impact on the fermentation of non-digestible carbohydrates and subsequent short chain fatty acids production, but only for a microbiome with high diversity and a predominance of microbes associated with dietary fiber intake. Subsequently, five processing methods: boiling, extrusion, unleavened bread, yeast bread, and sourdough ...