This dissertation is composed of three manuscripts focusing on food insecurity and food economics in the United States. The first manuscript titled ``Differences in Food Insecurity Across the Rural/Urban Spectrum - The Role of Trade Flows" uses county food trade data to examine its correlation with food insecurity rates based on a county's rural-urban continuum code. In addition, an Oaxaca-Blinder decomposition is employed to determine the causes of food insecurity rate differences between county's based on their rural-urban continuum codes. The second manuscript titled ``The Role of Infrastructure on Food Flows in the United States" uses county food trade data to examine the relationship between county infrastructure important to the food supply chain, such as roadways, ports, food processing and manufacturing plants, grocery stores, supercenters, and restaurants, and the impact on food trade between counties. Specifically, two types of food trade from two Standard Classification of Transported Goods categories are analyzed: agricultural products, and other food stuffs. A Poisson pseudo-maximum likelihood model is employed to account for the zero-trade flows observed between counties. The analysis determines that certain infrastructure has an important impact, and the impact can differ depending on the type of goods category. The third manuscript, "Reactions to Food Safety Recalls Among Food Insecure and Food Secure Households" examines the behavioral responses of food secure and food insecure persons to a hypothetical food safety recall using a vignette approach. The analysis finds that reactions can differ across demographics, including those of food insecure individuals. / Doctor of Philosophy / This dissertation focuses on two areas in agricultural and applied economics: food insecurity and food economics. In the first manuscript, I examine how certain types of food trade among counties in the United States impacts a county's food insecurity rate. I also determine how this impact changes based on a county's rural/urban status. Depending on the type of food that is traded, I find that food trade can have an impact on county food insecurity rates. Additionally, the impact of food trade on food insecurity rates differs depending on the rural/urban status of a county. In the second manuscript, I use county food trade data to analyze the drivers of food trade between counties in the United States. Specifically, I examine how a county's infrastructure encourages or discourages the trade of agricultural products and other foodstuffs. I find that infrastructure like roadways, food processing and manufacturing plants, and ports are important drivers of food trade between counties. Lastly, in the third manuscript, I study how food insecure and food secure persons might react differently to a food safety recall of eggs or romaine lettuce. Specifically, I determine how attributes such as price, travel time to a store, and risk of illness from consumption of a recalled food affect a person's decision to throw away, consume, or refund a recalled food. I find that price and travel time to a store impacts this decision. Additionally, I find that demographics such as a person's food insecurity status, race, age, and gender can influence their reaction to a food safety recall in some cases.

In 2024 a new method of conducting food safety control in Sweden will be implemented. One of the changes is the way businesses are classified according to the risk they pose; another is the transition to direct debiting instead of yearly fees. This changes the practice of food safety control in Sweden and the affected regulatory authorities and food business operators will need to alter their methods. This study aims to investigate if the implementation of these changes is efficient, how it is received by regulatory authorities and, by extension, how organisational changes in general affect the working environment and how attitudes can affect their implementation. A large-scale change is naturally met with some resistance that may affect how beneficial it ultimately is. In this case the changes seem to be moderately well-received but there is some criticism, most of which is connected to the reduction of control time for businesses close to consumers. There is also a worry that the change will be administratively heavy and large municipalities express more concern than small ones, possibly due to the large number of businesses they are responsible for. The transition to direct debiting is believed to be a positive change for food business operators but time-consuming for regulatory authorities. Further evaluation after these changes have come into force is needed to learn their actual effect on food safety control.

Bio-interface topography strongly affects the nature and efficiency of interactions with living cells and biological molecules, making hydrogels decorated with micro and nanostructures an attractive choice for a wide range of biomedical applications. Despite the distinct advantages of protein hydrogels, literature in the field has disproportionately focused on synthetic polymers to the point that most methods are inherently incompatible with proteins and heat-sensitive molecules. We report the development of multiple biomolecule-friendly technologies to construct microstructured protein and bacteriophage (bacterial virus) hydrogels. Firstly, ordered and sphericity-controllable microbumps were obtained on the surface of protein hydrogels using polystyrene microporous templates. Addition of protein nanogels resulted in the hierarchical nano-on-micro morphology on the microbumps, exhibiting bacterial repellency 100 times stronger than a flat hydrogel surface. The developed microstructures are therefore especially suitable for antifouling applications. The microstructures created on protein hydrogels paved the way for applying honeycomb template on proteinous bacterial viruses. We developed a high-throughput method to manufacture isolated, homogenous, pure and hybrid phage microgels. The crosslinked phages in each phage-exclusive microgel self-organized and exhibited a highly-aligned nanofibrous texture. Sprays of hybrid microgels loaded with potent virulent phage effectively reduced heavy loads of multidrug resistant Escherichia coli O157:H7 on food products by 6 logs. / Thesis / Doctor of Philosophy (PhD) / Bacteriophages (bacterial viruses), also known as phages, are natural bacteria predators. These viruses act as direct missiles, each phage targeting limited groups of bacteria. In addition, phages are an endless resource for self-propagating nanoparticles that can be used as building blocks for new material. I developed a platform for manufacturing a large quantity of microscale beads made of millions of phages. These micro-beads can be sprayed on fresh produce and meat to remove bacterial contamination (with the added benefit of not affecting taste or smell). I also printed phages on substrates, like an ink. The printed phage ink evolved into a patented technology for designing phage coatings on surfaces with very high surface area, like the small structures on our fingers. This phage coating was successfully used to test the existence of bacteria in liquids.

Reducing the frequency of Salmonella in broiler flocks is important from both the standpoints of food safety consumer protection and industry viability. The goal of this dissertation is to provide a more complete identification, characterization and assessment of significance of the risk factors potentially associated with broiler flock Salmonella status as the flock progresses through sequential segments of the production continuum. The sequential segments of the continuum are: broiler breeders and hatchery, transportation from hatchery to grow-out farm, grow-out, transportation from farm to processing plant and processing. In this study broiler flocks were sampled through an entire grow-out production cycle, starting from the flock?s arrival from the hatchery to the grow-out farm, then, at the end of grow-out, upon arrival to the processing plant, and at the pre-chill and post-chill points of processing. Litter samples and drag swabs of the litter were collected in the grow-out house prior to placement and after the harvest of the flock. Epidemiological tools, questionnaires and checklists, were developed and utilized together with the company production records, soil, climatologic and other data to characterize potential risk factors of grow-out broiler flock Salmonella status. Regression modeling was used to investigate associations between the described risk factors and the sampled flock?s Salmonella status. Interrelationship of the flock and grow-out environment Salmonella status at the sequential production segments was studied as a risk factor. Models were built to describe the risk factors of Salmonella contamination of the litter and drag swabs collected in the grow-out house prior to placement of the birds. Following, models were built to identify the risk factors associated with broiler flock Salmonella status upon delivery from the hatchery to the farm and at the end of the grow-out.

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The development of rapid detection methods for bacterial contamination in the industrial agriculture sector is vital for improving food safety and public health. Furthermore, it is important to tailor these rapid methods for low-resource settings, because the majority of foodborne illness outbreaks occur in developing nations. Currently, the most widely used methods rely on nucleic acid testing using the polymerase chain reaction (PCR). This detection reaction provides repeatable results, is highly sensitive, and is highly specific, as it can detect a single strain within a species. However, PCR is reliant on proper sample pre-treatment to remove inhibitory contaminants which can affect downstream results, which leads to a trade-off between detection time and sensitivity of results. Rolling circle amplification (RCA) is another potential detection reaction which has the same advantages and is also better suited to low-resource settings, as it works at room temperature. This thesis reports on the development of a rapid sample preparation method that can be seamlessly integrated into simple PCR and is also well suited to low-resource settings due to the low cost and high availability of the required reagents. A modification of the hot sodium hydroxide plus tris (HotSHOT) lysis reaction was implemented to extract genomic DNA (gDNA), which was then captured onto cellulose filter paper, allowing for multiple samples to be simultaneously processed in under 30 minutes. This pre-treatment can even recover gDNA for detection from samples that would have caused complete inhibition of PCR. The calculated limit of detection (LoD) of extraction followed by simple PCR was similar to that of government-approved commercial kits, without needing a lengthy bacterial enrichment step. Improvements are needed to make this a truly quantitative detection system. Finally, our paper-based pre-treatment was integrated into an RCA reaction to detect at least 105 cells, which provides proof-of-concept for combining paper-based sample preparation with isothermal amplification of target nucleic acids. / Thesis / Master of Applied Science (MASc)

There were an estimated 11.1% of households experiencing food insecurity in the U.S. in 2018, meaning that they did not have the adequate resources to access safe, nutritious food at some point in the year. In order to support people experiencing food insecurity and related-hunger, national organizations, regional food banks, and local programs operate to recover, organize, and distribute the food available to them. Food recovery work falls into a regulatory grey-area. Should anyone consuming donated food become ill, the food handlers would not be criminally or civilly liable if they distributed it in good faith. There are no federal regulations covering food handling in food recovery, though some states do have such regulations. As a result, safe food handling guidance, education, and training is offered through organized networks and Cooperative Extension. Participating in educational programs increases safe food handling knowledge, however volunteers and employees in food recovery organizations have also been observed to unsafely handle food. Additionally, these resources can be limited in their scope and some are only accessible through membership in pre-existing networks such as Feeding America. The purpose of this work is to further document how food is handled in food recovery and compliment that by collecting the experiences and perceptions of these food handlers as well as Cooperative Extension educators who support them. This work utilized a mixed-methods approach to quantify behaviors and experiences, which compliments qualitatively collected contextual information. Food handlers serving with a university-based student food recovery program, which works to distribute unserved and unsold food from on-campus dining centers, were observed improperly washing their hands, inconsistently keeping records, and using unclean or otherwise contaminated equipment. These behaviors could be addressed through rolespecific education representing their unique operations. Virginia Cooperative Extension (VCE) educators were used as a case study to measure their experiences when supporting food recovery, with 41% of respondents having previously supporting an organization or program. Topics covered ranged from safe food handling, network leadership, financial planning, and farming/gardening. VCE educators expressed a sense of altruism when supporting food recovery organizations, but also experienced challenges such as not having enough time to fully engage or the organization not having adequate equipment to enact their support. VCE educators who had not previously supported these organizations expressed wanting to learn more about food recovery work and how VCE can support them. Employees of food banks believe current food safety education could be improved by offering role-specific information in customizable formats so the food handlers can translate their knowledge into action. Future education should also focus on problemsolving, so food handlers feel empowered to react to expected challenges. Lastly, to account for challenges experienced while conducting this research, future projects within the context of food recovery should consider the limited time available of potential participants, offer compensation for their participation, and maximize pre-existing networks when connecting with them. / Doctor of Philosophy / There were an estimated 11.1% of households experiencing food insecurity in the U.S. in 2018, meaning that they did not have the adequate resources to access safe, nutritious food at some point in the past year. In order to support people experiencing food insecurity and related-hunger, national organizations, regional food banks, and local programs operate to recover, organize, and distribute the food available to them. Food recovery work falls into a regulatory grey-area. Food handlers are not criminally or civilly liable should anyone become ill as a result of consuming food when it is donated in good faith, and guidance in the form of food handling regulations for food recovery varies from state-to-state and is not addressed federally. As a result, safe food handling education and training is offered through organized networks and Cooperative Extension. Participating in educational programs increases safe food handling knowledge, however volunteers and employees in food recovery organizations have also been observed to unsafely handle food. Additionally, these resources can be limited in their scope with some only accessible through membership in pre-existing networks. The purpose of this work is to further document how food is handled in food recovery, which will complement the collection of experiences and perceptions of food handlers and Virginia Cooperative Extension (VCE) educators who support them. Volunteers serving with a university-based student food recovery program, which works to distribute unserved and unsold food from their on-campus dining centers, exhibited a combination of safe and unsafe food handling behaviors which could be addressed through role-specific education representing their unique operations. VCE educators expressed a sense of altruism when supporting food recovery organizations across a range of topics, however they also expressed wanting to know more about their operations and how VCE can support them. Employees of food banks believe current food safety education could be improved by offering role-specific information in a variety of formats paired so the food handlers can translate their knowledge into action. Lastly, to account for challenges experienced while conducting this research, future projects within the context of food recovery should consider limited time potential participants have to serve as well as maximize preexisting networks when recruiting them.

The growing popularity of farmers' markets coupled with a high percentage of produce-related foodborne outbreaks highlights the need for an emphasis on food safety within these markets to protect farmers, patrons and local economies. The number of farmers' markets registered in the United States has almost tripled in the last 15 years. Fresh produce constitutes the majority of food sold at farmers'markets. Between 1998 and 2008, raw produce accounted for almost half of the 4,589 foodborne illness outbreaks linked to a specific commodity. This research was conducted to identify practices at farmers' markets which may contribute to an increased risk of contamination, assess the microbial quality of produce sold at farmers' markets, as well as to develop a food safety management plan template for market managers to utilize to build their own food safety plan. Using an observational data collection method, risky food safety practices were identified at Southwest Virginia farmers' markets. While market managers and vendors in three of the five markets observed had formal food safety training, numerous risky food safety behaviors were still observed including temperature abuse, cross contamination opportunities, and poor personal hygiene and sanitation. Additionally, the microbial quality of produce from Southwest Virginia farmers' markets was compared to produce sold at retail using culture based microbiological plating and molecular methods. Total aerobic bacteria and coliforms were enumerated, and the presence of Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus and generic E. coli were determined. A significantly greater quantity of total aerobic bacteria was isolated from farmers' market leafy greens, onions and tomatoes when compared to a retail grocery store (P=0.0011, P=0.0395, and P<0.0001, respectively). Additionally, one or more target pathogen was isolated from 28 farmers' market samples and 16 retail grocery store samples. The observed risky food safety behaviors along with the bacterial data collected emphasize the need for a pathogen reduction focus on fresh produce not only at farmers' markets, but also with growers and other retail outlets. To help promote proper food safety practices at farmers' markets, a farmers' market food safety management plan (FSMP) template was developed to address the top five risk factors contributing to foodborne illness as identified by the Centers for Disease Control and Prevention (CDC). The FSMP was evaluated for practicality and feasibility through interviews with market mangers in North Carolina and Virginia. Most market managers (66.7%) agreed that the FSMP was practical for their market while only 33.3% agreed that they could implement the plan immediately. Revisions suggested to the FSMP will be made and it will be made available in Virginia and North Carolina in spring 2016. / Ph. D.