Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 9 of 9

Full-Text Articles in Life Sciences

Biopolymer Electrospun Nanofiber Mats To Inactivate And Remove Bacteria, Katrina Ann Rieger Nov 2016

Biopolymer Electrospun Nanofiber Mats To Inactivate And Remove Bacteria, Katrina Ann Rieger

Doctoral Dissertations

The persistence of antibiotic resistance in bacterial pathogens remains a primary concern for immunocompromised and critically-ill hospital patients. Hospital associated infections can be deadly and reduce the successes of medical advancements, such as, cancer therapies and medical implants. Thus, it is imperative to develop materials that can (i) deliver new antibiotics with accuracy, as well as (ii) uptake pathogenic microbes. In this work, we will demonstrate that electrospun nanofiber mats offer a promising platform for both of these objectives because of their high surface-to-volume ratio, interconnected high porosity, gas permeability, and ability to contour to virtually any surface. To provide ...


Label-Free And Aptamer-Based Surface Enhanced Raman Spectroscopy For Detection Of Food Contaminants, Shintaro Pang Nov 2016

Label-Free And Aptamer-Based Surface Enhanced Raman Spectroscopy For Detection Of Food Contaminants, Shintaro Pang

Doctoral Dissertations

The development of analytical methods to detect food contaminants is a critical step for improving food safety. Surface enhanced Raman spectroscopy (SERS) is an emerging detection technology that has the potential to rapidly, accurately and sensitively detect a wide variety of food contaminants. However, SERS detection becomes a challenge in real complex matrix, such as food, since non-specific matrix signals have the potential to drown out target associated Raman peaks. In this dissertation, we focused on the development and application of label-free, aptamer-based SERS in order to improve the accuracy and specificity of target contaminant detection in food. To accomplish ...


Bacteriophage-Based Colorimetric Detection Of Escherichia Coli In Drinking Water, Juhong Chen Nov 2016

Bacteriophage-Based Colorimetric Detection Of Escherichia Coli In Drinking Water, Juhong Chen

Doctoral Dissertations

One of the major safety causes in drinking water is from the bacteria contamination, especially in developing countries and resource-limited settings. Although many of these Escherichia coli (E. coli) strains in drinking water are nonpathogenic, they sever as the indicator for bacterial contamination. And, the more widely used method to detect E. coli in drinking water is to determine the activity of β-galactosidase (β-gal), which is released by E. coli. Rapid, sensitive and inexpensive detection of E. coli in drinking water can reduce the risk of food-borne bacteria infection and stop the disease widely spreading.

In this degree research, phage-based ...


Encapsulation Of Probiotic Microorganisms In Food-Grade Hydrogel Microbeads For Improving Long-Term Storage And Oral Delivery, Timothy W. Yeung Nov 2016

Encapsulation Of Probiotic Microorganisms In Food-Grade Hydrogel Microbeads For Improving Long-Term Storage And Oral Delivery, Timothy W. Yeung

Masters Theses

Probiotics die over time during processing, storage and digestion, resulting in reduced health benefits to the consumer. Microencapsulation of microorganisms is an effective way to improve probiotic viability by restricting cell exposure to extreme conditions through the gastrointestinal tract until release in the colon. In this work, appearance and survival of encapsulated probiotic species from two genera was explored. Lactococcus lactis and Bifidobacterium longum were suspended in calcium alginate microbeads by spraying droplets of alginate-probiotic mixture into calcium chloride solution. This produced uniformly shaped transparent microbeads with high encapsulation yield. Encapsulating Lactococcus lactis extended viability during dry room temperature storage ...


Distribution Of Enterotoxigenic Clostridium Perfringens Spores In U.S. Retail Spices, Chi-An Lee Nov 2016

Distribution Of Enterotoxigenic Clostridium Perfringens Spores In U.S. Retail Spices, Chi-An Lee

Masters Theses

246 samples of bulk and packaged spices from retail stores in the western, southeastern, southern, midwestern, and northeastern areas of the U.S. were examined for the presence of Clostridium -perfringens. Isolates were checked for the presence of the lecithinase gene (cpa) and enterotoxin genes (cpe) by PCR. Enterotoxin formation during sporulation was investigated using the Oxoid Toxin Detection Kit. Forty-three confirmed isolates (from 17% of total samples) were cpa-positive. Of those, 27 were cpe-positive. Together, levels of C. perfringens spores ranged from 3.6-2400/gm. The amount of enterotoxin in cell extracts ranged from 2-16 ng/ml ...


Novel Advancements For Improving Sprout Safety, Kyle S. Landry Jul 2016

Novel Advancements For Improving Sprout Safety, Kyle S. Landry

Doctoral Dissertations

All varieties of bean sprouts (mung bean, alfalfa, broccoli, and radish) are classified as a “super-food” and are common staples for health conscious consumers. Along with the proposed health benefits, there is also an inherent risk of foodborne illness. When sprouts are cooked, there is little risk of illness. The purpose of this dissertation was to explore novel techniques to minimize or prevent the incidence of foodborne illness associated with the consumption of sprouts. Three areas were investigated: 1) the use of a biocontrol organism, 2) the use of a novel spontaneous carvacrol nanoemulsion, and 3) the influence of the ...


Enzymatic Digestion Improved Bacteria Separation From Leafy Green Vegetables, Danhui Wang Jul 2016

Enzymatic Digestion Improved Bacteria Separation From Leafy Green Vegetables, Danhui Wang

Masters Theses

An effective and rapid method for the separation of bacteria from food matrix remains a bottleneck for rapid bacteria detection for food safety. Bacteria can strongly attach to the food surface or internalize within the matrix which makes their isolation extremely difficult. Traditional methods of separating bacteria from foods routinely involve stomaching, blending and shaking, however these methods may not be efficient at removing all the bacteria from complex matrices. Here, we investigate the benefits of using enzyme digestion followed by immunomagnetic separation to isolate Salmonella from spinach and lettuce. Enzymatic digestion using pectinase and cellulase was able to break ...


Echerichia Coli Biofilm Formation In Musca Domestica Crops, Lufan Wang Mar 2016

Echerichia Coli Biofilm Formation In Musca Domestica Crops, Lufan Wang

Masters Theses

The house fly, Musca domestica can transmit human pathogens including Escherichia coli O157:H7 through regurgitation of ingested bacteria from the crop which is a foregut organ of house fly and stores the excess ingested nutrients. Interactions between the ingested bacteria and the crop have a direct influence on bacteria persistence, survival and ultimately fly vector competence. In this research, in situ crop vessel assay was developed to investigate bacterial growth within fly crops up to 48 hours post-ingestion. Flies were fasted for 12 h prior to feeding E. coli O157:H7 pEGFP and then fed bacteria with ...


Influence Of Inoculum Preparation Upon Sensitivity Of Common Food Borne Pathogens To Emulsion Based Antimicrobials, Dillon Sd Murray Mar 2016

Influence Of Inoculum Preparation Upon Sensitivity Of Common Food Borne Pathogens To Emulsion Based Antimicrobials, Dillon Sd Murray

Masters Theses

Antimicrobial optimization procedures use the most resistant bacterial culture that could be present in the food to determine the levels of treatment needed to ensure safety. These procedures usually only focus on one method of preparing these inoculums for testing despite prior research showing that the preparation of the culture can influence how the culture reacts to a treatment. In this work, planktonic cells grown in a liquid media and sessile cells grown on a similar solid media were subjected to identical emulsion based antimicrobial systems. The cultures were monitored over time and their numbers periodically enumerated. Weibullian destruction models ...