<p dir="ltr">Liquid hydrogen peroxide (LHP) and vapor hydrogen peroxide (VHP) efficacy as a sterilant for <i>Bacillus atrophaeus</i> and <i>Geobacillus stearothermophilus</i> spores in aseptic packaging systems under commercial sterilization conditions were evaluated in this research. The work centers on quantifying and modeling the kinetic parameters that impact peroxide sterilization efficacy, including the D and z values, that relate to the change in concentration required for a 1-log reduction in spore population and a novel Z_conc parameter This comprehensive study is divided into four key investigations, each contributing critical insights to the overall understanding of peroxide sterilization processes.</p><p dir="ltr">The first study examined the inactivation kinetics of <i>B. atrophaeus</i> spores in liquid hydrogen peroxide. By evaluating different concentrations (20%, 28%, and 33%) and temperatures (up to 82.2°C), the study revealed that higher concentrations and elevated temperatures significantly enhanced spore inactivation. The Weibull model provided a more accurate fit for the data, indicating a non-linear relationship between spore reduction and exposure time.</p><p dir="ltr">The second part of the research explored the use of VHP for sterilizing <i>B. atrophaeus</i> spores. With VHP concentrations of 2500 ppm and 4450 ppm at various temperatures, the study demonstrated that higher concentrations and temperatures are highly effective for spore inactivation. Both log-linear and Weibull models accurately described the inactivation kinetics, with the Weibull model showing a slightly better fit, emphasizing the potential of VHP in achieving commercial sterility.</p><p dir="ltr">The third investigation focused on developing predictive models for VHP concentration and its efficacy in spore inactivation. The study evaluated VHP concentrations ranging from 2.32 mg/L to 7.35 mg/L and their impact on spore inactivation rates. The Weibull model proved particularly effective in predicting the inactivation of <i>G. stearothermophilus</i> and <i>B. atrophaeus</i> spores, offering a robust tool for optimizing sterilization protocols in aseptic packaging.</p><p dir="ltr">The fourth and final study of the research investigated the influence of surface roughness on spore survival during VHP sterilization cycles on plastic packaging materials. Artificial roughness on high-density polyethylene (HDPE) coupons was created using sandpaper with different grits. <i>B. atrophaeus</i> spores were applied to both roughened and smooth HDPE surfaces. The study finds that rougher surfaces provide more shelter for spores, reducing sterilization efficacy. For example, surfaces roughened with P-36 grit showed a 2.75 log reduction in spore count, whereas smoother surfaces with P-220 grit achieved a 4.42 log reduction. Contact angle measurements indicated that increased roughness led to more hydrophilic surfaces, with water contact angles decreasing from 149.7° for the pristine sample to 105.4° for the P-36 sample. Scanning electron microscopy (SEM) images confirmed that spores were more likely to reside in the valleys of rough surfaces, highlighting the importance of surface characteristics in optimizing VHP sterilization protocols.</p><p dir="ltr">The findings of this dissertation underscore the significant impact of hydrogen peroxide concentration, application conditions, and packaging material surface properties on the efficacy of spore inactivation during sterilization. By providing a comprehensive understanding of these factors, the research contributes to the development of optimized aseptic sterilization protocols, enhancing the reliability and safety of aseptically packaged food and pharmaceutical products. This work will ensure compliance with regulatory standards and improve food safety in commercial manufacturing, laying a solid foundation for future research and practical applications in VHP sterilization technology.</p>

This dissertation examines how concerns about food system transformations affect how middle class consumers in Islamabad, Pakistan, perceive and approach food consumption in their everyday lives. The dissertation is situated in the context of risky food environments and food fears resulting from intensified, industrialised, and increasingly lengthened global food systems. Working within food geography and food environments paradigms, this dissertation explores how the transformation of food systems is associated with increasing anxiety about food security and safety for middle class urban consumers in Islamabad. Qualitative data gathered from semi-structured interviews and participant observation is used to illustrate the effects external influences, such as energy scarcity and violent events, have on everyday food environments. The dissertation examines the ways in which conceptualisations of 'good food', and trust relationships are negotiated in these dynamic food environments. The intensely geographical nature of these food environments and food systems, and the role of place-specific contexts on perceptions and adaptations related to food anxieties are emphasised. Situated in literatures on food anxiety and food consumption emerging from geography, food studies, and anthropology, this dissertation challenges dominant discourses on alternative and ethical consumption in a globalising food system. The results of this research not only contribute to literature on South Asia, but also contribute to consumption practices of a burgeoning middle class in developing countries.

<p>  </p> <p>Food system STEM projects have the capacity to motivate high school students in urban schools. This study explored food as a context to engage students because everyone interacts with food on a daily basis and has had cultural experiences related to food. An integrated STEM approach in combination with a systems thinking approach challenged students to make transdisciplinary connections, view problems from different perspectives, analyze complex relationships, and develop 21st-century and career skills (Hilimire et al., 2014; Nanayakkara et al., 2017). The purpose of this study was to describe and explain the relevance students perceive in Ag+STEM content by measuring high school students' self-efficacy, intrinsic value, attainment value, cost value, and utility value after participating in a food system STEM project. The study was informed by Eccles and Wigfield’s (2020) Situated Expectancy Value Theory. The convenience sample of this study was comprised of high school students from metropolitan area schools. High school students completed a food system STEM project with a food system context. Quantitative data was collected using the developed Food System Motivation questionnaire. Data were collected through a retrospective pre-test and a post-test. Descriptive statistics were used to analyze the data including means and standard deviations. Relationships were explored by calculating correlations.</p> <p>There were four conclusions from this study. First, high school students were somewhat interested, felt it was important to do well, and agreed there were costs regarding participation in the food system STEM project. Second, high school students reported higher personal and local utility value motivation after completing the food system STEM project. Third, high school students were somewhat self-efficacious in completing the project tasks and completing the project tasks informed by their cultural identity and experiences. Fourth, intrinsic value and attainment value motivation (independent variables) were related to personal and local utility value motivation and project and cultural self-efficacy motivation (dependent variables). Implications for practice and recommendations for future research were discussed.</p>

Att ta itu med hållbarhet i livsmedel och minska livsmedelsindustrins miljöpåverkan har avgörande betydelse. Inom detta sammanhang har måltidsplanering framstått som en betydande faktor som påverkar matbeteendet och bidrar till att minska hushållsavfallet. Denna forskning fokuserar på att undersöka effekten och effektiviteten av en måltidsplanerings som syftar till att minska avfallet. För att åstadkomma detta användes en blandad Research through Design-process (RtD), som inkluderade metoder som brainstorming och observationsmetoder. Forskningsresultaten visar att genomförandet av en måltidsplanering framgångsrikt kan förbättra användningen av ingredienser inom hushållen, vilket leder till minskat avfall. Designegenskaper som stödjer individer i deras måltidsplanering identifierades: ha planeringen på ett och samma ställe, inkludera uppmaningar med syfte att uppmuntra individer att följa planen, och visa framstegen under hela måltidscykeln. Vidare identifierades designegenskaper som stödde matlagning i hemmet: att ha systemet och måltidsplanen synliga för användaren, samt att dela upp ingrediensen till måltiderna i fack. Sammantaget hjälper dessa identifierade designegenskaper individer att delta i måltidsplanering, vilket leder till minskat hushållsavfall. / Addressing food sustainability and reducing the environmental impact of the food industry are crucial concerns. Within this context, meal planning has emerged as a significant factor influencing food behaviour and contributing to the reduction of domestic waste. This research focuses on investigating the impact and effectiveness of a meal planning intervention aimed at the reduction of waste. To accomplish this, a mixed Research through Design (RtD) process was employed, incorporating methods such as brainstorming sessions and observational methods. The research findings reveal that implementing a meal planning intervention can successfully enhance ingredient utilisation within households, which leads to waste reduction. Design properties that support individuals in their meal planning efforts were identified: having the planning process all in one place, incorporating prompts to encourage individuals to adhere to the plan, and showcasing the progress throughout the meal cycle. Furthermore, design properties that supported cooking in the home were identified: having the system and the meal plan visible to the user, and dividing the ingredient for the meals into compartments. Overall, these identified design propertied collectively assist individuals in engaging in meal planning, leading to the reduction of domestic waste.

<p dir="ltr">Seafood plays a pivotal role in global economies, livelihoods, and nutritional security. However, climate change and global pandemics pose significant threats to seafood harvests, production, supply chains, and marketing channels. The focus of my thesis is to understand the impact of external factors on our seafood resources and explore adaptive strategies in the face of uncertainties. We utilize economics techniques to study human-nature systems by zooming into social elements (government agencies, industry stakeholders, and fish farmers/fishermen) and aquatic resources. The three essays of my thesis delve into this inquiry from the perspectives of government, industry, and market, accordingly.</p><p dir="ltr">The first chapter in my thesis, <i>Climate Change and Snow Crab Harvest - Applying Random Effect Estimators with Instrumental Variable</i>, estimates the snow crab harvest function with unbalanced panel data of eastern Bering Sea snow crab, Canadian snow crab, Japanese snow crab, and Barents Sea snow crab. Specifically, we analyze the relationship between snow crab biomass, stock, and catch. To address the endogeneity of stock in the harvest function, climate change indicators are selected as instrumental variables. We identify that the Arctic Sea ice extent is effective in addressing the endogeneity and the random effects instrumental variable model with error components two stage least squares estimator performs the best to control heterogeneity. We find that a 1% increase in snow crab fishing effort is associated with a 0.42% increase in snow crab harvest, and a 1% increase in snow crab stock causes a 0.98% increase in snow crab harvest. The reported estimates indicate a large stock-harvest elasticity and provide supporting evidence for government fishery agencies to prioritize stock enhancement in policy designs.</p><p dir="ltr">The second chapter, <i>Online Media Sentiment Analysis of Shrimp and Salmon in the United States</i>, employs online media analytics on shrimp and salmon in the US to provide insights into consumer perceptions and potential demand signals for seafood. Search hits and mentions are quantified for top sources, domains, and prevalent terms. In addition, sentiment drivers and sentiment values are identified and calculated using natural language processing tools. The results reveal that the occurrence of peak mentions does not necessarily coincide with the peak of net sentiment, and farmed seafood consistently exhibits lower net sentiments compared to their wild counterparts. Autoregressive modeling is conducted to predict the dynamics of seafood’s net sentiments. The regional analysis demonstrates that public attitudes toward both farmed shrimp and salmon in the East North Central region exhibit a more positive net sentiment, while the New England and Middle Atlantic regions tend to have a lower net sentiment for farmed shrimp and salmon, respectively. The fitted forecast model serves as a supplementary tool for industry stakeholders to quickly respond to future public perceptions. Regional statistics also help the seafood industry tailor business strategies to different regions.</p><p dir="ltr">In the third chapter, <i>Comparative Case Study of Small-Scale Fish Processing for Local Seafood Supply</i><i>,</i> we examine the feasibility of utilizing a shared-use commercial kitchen and on-farm kitchen to support small-scale local fish processing, which helps diversify marketing channels in the US Midwest and supply seafood to local food systems. A case study of each facility type is assessed for economic viability for fish farmers. The financial analysis suggests farmers interested in processing tilapia or rainbow trout from 2,500 lbs to 5,000 lbs per year utilize rental commercial kitchens. A minimum of 15% markup and processing of 10,000 lbs/year tilapia is required to make the on-farm kitchen option more viable. For farmers who process rainbow trout, 10,000 lbs/year with a 10% markup using an on-farm kitchen is a better choice. Factoring in the stochastic variability of raw product prices, rental rates, and set-up costs, we provide simulated ranges for economic metrics including profitability index, payback period, and net present values. The reports of estimated costs, revenues, and breakeven prices, provide fish farmers with suggested selling prices, kitchen choices, and production levels to achieve optimum profits under risks.</p>