La presenten investigación busca determinar el efecto del nivel educativo de los jefes del hogar sobre la seguridad alimentaria de los hogares peruanos. El análisis se realiza a través del modelo Tobit con el fin de evidenciar cuales son los factores y en que cantidad; es decir, busca determinar si el impacto del nivel educativo de los padres es positivo o negativo, junto a otros determinantes dentro del hogar, y cuánta es la probabilidad de ocurrencia de que un hogar cuente con seguridad alimentaria. La investigación concluye que un hogar cuente con seguridad alimentaria, medida como el gasto alimentario del hogar, si los jefes del hogar tienen un nivel educativo más alto junto con mayores ingresos. / This research project aims to determine the effect of the educational level of household heads on the food security of Peruvian households. The analysis is carried out through the TOBIT model in order to show which are the factors and in what quantity. That is, aims to determine whether the impact of the parent’s educational level is positive or negative, together with other determinants within the household has food security. The research concludes that a household has food security, measured as the household’s food expenditure, if the heads of the household have a higher educational level along with higher income. / Trabajo de investigación

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Low water activity foods (LWAF), specifically nuts and dried fruits, have been generally considered safe because they do not support the growth of foodborne pathogens. However, many pathogens have been noted to survive in LWAF for considerable periods of time, and a number of recent outbreaks and recalls have implicated various types of nuts and dried fruits. The Food Safety Modernization Act requires food processors to develop preventive control plans that make ready-to-eat LWAF safer for consumers. The presented research was designed to investigate several aspects of LWAF safety by evaluating a steam process as a strategy to remove pathogen contamination from LWAF, modeling the inactivation of such treatments, and studying the thermal resistances of two E. coli strains in low-water activity solutions. Low-temperature, vacuum-assisted steam (vacuum-steam) was evaluated as a potential intervention and preventive control to remove pathogens from the surface of LWAF without using high-heat treatments that could damage product quality. The presented work examined the efficacy of vacuum-steam (<85°C) as a means to decontaminate the surface of whole macadamia nuts, dried apricot halves, and raisins from Salmonella spp., Listeria monocytogenes, and Shiga toxin-producing Escherichia coli (STEC) contamination. The low-temperature steam treatments successfully reduced all pathogens by >4 log CFU/g from the surfaces of the foods. Additionally, Pediococcus acidilactici, proved to be a surrogate organism for these pathogens and could be used to challenge and validate similar treatments within processing plants. The data were fit to models, which showed that food type significantly impacted the fit, with the Weibull model best describing bacterial inactivation kinetics on raisins and macadamia nuts, and the Gompertz model best describing reductions on the apricot halves. The models were challenged for validation of their abilities to predict times required for 3-log reductions using internal and external datasets, determining the usefulness to industry members who wish to design similar thermal treatments for LWAF. Comparing predicted values from internally constructed models to observed values generated from external data, models were shown to be limited in scope and application and could only be applied to pathogen inactivation on different LWAF or thermal processes in certain circumstances. First-order and Weibull model predictions of bacterial reductions on dried apricots had varied success in predicting times for 3-log reductions on other thermally treated LWAF. However, the models of bacterial reductions on thermally treated macadamia nuts frequently overestimated the times required for 3-log bacterial reductions for other LWAF. In an effort to understand the effect that reduced water activity has specifically on STEC, two strains were investigated for induced thermal resistance due to osmotic stress. Thermal resistance of STEC strains (O121:H19 and O157:H7) were evaluated on the basis of strain variation, culture preparation, and water activity (D- and z-values). At the lowest treatment temperature (56°C), O121 displayed greater heat resistance than O157, and the broth-grown samples exhibited greater heat resistance than the lawn-grown cells, but significant differences were not observed at higher temperatures. Samples in reduced-water activity solutions displayed reduced thermal resistance at 56°C, but the z-values were 29-43% higher than those of high-water activity samples. While water activity has been shown to impact thermal resistance of pathogens, comparisons of STEC thermal resistance according to the D- and z-values revealed that other factors also play roles in pathogen thermal resistance on LWAF. Results from the collection of experiments conclude that efficacy of thermal treatments is impacted by the physiological state of the cells, stress experienced in the food matrix, and characteristics of the food, including water activity and composition. / Doctor of Philosophy / Consumers expect foods they purchase to be safe to consume by themselves and family members, particularly those that are ready-to-eat with no additional cooking requirements. Many of these foods are low-water activity foods (LWAF), like nuts and dried fruits, with very little water content that could be used by bacteria. These foods may be preferred snack foods due to their affordability, long shelf lives, and health benefits over other types of snack foods. Until recently, LWAF were generally considered safe because they do not support the growth of foodborne pathogens due to the lack of moisture or water within the food. However, a number of recent outbreaks related to various types of nuts and dried fruits have proven that many pathogens can survive in dried foods, even if not actively growing, for considerable amounts of time. Designed to address these types of food safety issues, the Food Safety Modernization Act recognizes risks associated with foods and responded with regulations requiring food processors to take steps to make ready-to-eat LWAF, like nuts and dried fruits, safer for consumers. A popular strategy is to treat foods with heat to destroy pathogens, however the quality attributes of some nuts and dried fruits could be damaged by high-heat treatments like roasting. An alternative process uses a vacuum to form steam at lower temperatures, allowing for efficient heat transfer through water droplets to the surface of the foods, thus causing less damage to the foods without introducing too much moisture. This research evaluated how this process could be used by food processors to remove harmful bacteria from the surfaces of whole macadamia nuts, dried apricot halves, and raisins. Results indicated that the low-temperature steam treatments successfully reduced Salmonella, Listeria monocytogenes, and Shiga toxin-producing Escherichia coli (STEC) by >4 log CFU/g (>99.99%) from the surfaces of the foods. Additionally, a nonpathogenic lactic acid bacterium, Pediococcus acidilactici, exhibited similar or greater heat tolerance, which would allow food processors to use it as a substitute, or surrogate, for in-plant studies without introducing harmful bacteria into the food processing environment. Mathematical models were used to describe the trends of bacterial death due to the steam treatments, and the results indicated that the type of food significantly impacted the reduction of bacteria. The models were tested using additional data collected within our own laboratory, as well as others. Results indicated that some of the models could be used as predictors of bacterial death for similar LWAF but can only be applied with caution and consideration for the type of food and process. Additionally, two different E. coli strains associated with outbreaks (O121:H19 and O157:H7) were investigated to understand impacts of strain variation, growth method, and water activity on thermal resistance. Some differences in heat resistance were observed between the strains and between the growth methods. Additionally, the reduced water activity seemed to decrease the bacteria's ability to withstand some heat treatments. Overall, thermal resistance studies indicated that several factors, in addition to water activity, impact pathogens' development of resistance to heat treatments. The experiments' results show that there are complex relationships between bacteria and the food they inhabit. Food processors must consider these relationships in order to design the best thermal processes to make LWAF safe for consumers.

<p dir="ltr">This dissertation delves into three projects within the realms of image processing, computer vision, and machine/deep learning. The primary objective of the first project is the detection of heavy metal particle concentrations using microfluidic paper-based devices. The second project revolves around the analysis of crystals within microscopic images. The third project centers around zero-shot action recognition in video sequences, utilizing a multi-modality deep learning framework that is refined through prompt tuning to enhance its performance.</p>

<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>

En la Municipalidad Provincial de Lambayeque se viene generando inseguridad alimentaria de la mano con los procesos de la gestión administrativa del PVL. Cabe mencionar que, el programa evidencia carencias respecto al proceso adquisición de insumos desde años anteriores realizándose de manera inadecuada y obviando la normativa ley de contrataciones del estado. A ello, el presente trabajo de investigación, tiene como objetivo general poder determinar la GA y su incidencia en la adquisición de insumos alimenticios en el programa del vaso de leche de la Municipalidad Provincial de Lambayeque 2021, lo cual se desarrollaron los siguientes objetivos: Describir la GA en el proceso adquisición de insumos alimenticios del Programa de Vaso de Leche; Analizar el procedimiento de la gestión administrativa que incide en la adquisición de insumos alimenticios del Programa Vaso de Leche y Proponer acciones internas para optimizar el proceso de adquisición de insumos alimenticios del Programa Vaso de Leche. Asimismo, la investigación se presenta como enfoque mixto debido a que se busca la recopilación, el análisis e incluso la integración en proporción a investigación cuantitativa y a la vez cualitativa, de tipo aplicada siendo de nivel descriptivo, aplicando la técnica documental para la realización. Finalmente, realizando la investigación se determinó que efectivamente existen carencias en el proceso. Por ello se recomiendan acciones internas para optimizar el proceso y así conseguir la finalidad del programa social alimentario denominado PVL. / In the Provincial Municipality of Lambayeque, food insecurity has been generated hand in hand with the administrative management processes of the PVL. It is worth mentioning that the program shows deficiencies regarding the process of acquiring inputs from previous years, being carried out inadequately and ignoring the state contracting law regulations. To this end, the present research work has the general objective of being able to determine the GA and its incidence in the acquisition of food supplies in the glass of milk program of the Provincial Municipality of Lambayeque 2021, which the following objectives were developed: Describe the GA in the process of acquiring food supplies from the Glass of Milk Program; Analyze the administrative management procedure that affects the acquisition of food supplies for the Glass of Milk Program and Propose internal actions to optimize the process of acquisition of food supplies for the Glass of Milk Program. Likewise, the research is presented as a mixed approach because it seeks the collection, analysis and even integration in proportion to quantitative and qualitative research, of an applied type being of a descriptive level, applying the documentary technique for the realization. Finally, carrying out the investigation, it was determined that there are indeed deficiencies in the process. For this reason, internal actions are recommended to optimize the process and thus achieve the purpose of the social food program called PVL

我國向以「美食王國」享譽國際，各種美食不但曾為國人共同驕傲，亦帶來大量觀光人潮與經濟收入。未料，2011年5月「塑化劑事件」揭開我國食安風暴之黑幕，此後毒澱粉事件、黑心油事件等一連串黑心事件爆發，不但使國人對政府食品安全行政管制失去信心，亦讓我國美食商譽嚴重受創。 政府雖於每次食安事件爆發後，隨即召開相應之各種食安會議，提出相關管制改革措施；更透過數次修改食安法，不斷提高對違反法規黑心食品相關業者之罰則。然而食安事件仍不斷爆發，黑心食品不但數量未曾減少，反而製造、加工方法更趨黑心；顯示我國食品安全行政管制完全失靈，傳統法執行制度陷入困境，亟需改革。 我國食安法於2013年6月進行重大修正，此次修正納入以預防原則為前提之風險分析模式，風險分析模式係由歐盟開始發展，主要包括風險評估、風險管理及風險溝通。我國雖擬納入風險分析模式革新食品安全管制，惟食安法似僅將核心置於風險評估之制度設計，有關風險管理措施著墨不多，風險溝通更是付之闕如。因此，修法2年多以來，食品安全仍未能有效管制，食安事件爆發後，更是主管機關手忙腳亂，消費者人心惶惶。 有鑑於傳統法執行制度陷入困境，無法完成食安管制之任務，食安法除納入風險分析模式外，尚設立三級管理機制，亦即採取公私協力與自主規制之手段，主要透過業者自我管理、建立通報系統等措施強化食安管制。藉由與私部門之合作，固可提高食安管制之專業與效率，惟因我國未能體察社會民情與企業文化之差異，徒使自主規制成為政府卸責之藉口，有待進一步檢討。 因此，我國應就食品安全管制應就立法政策、風險分析及供應鏈管制等三方面，徹底檢討並提出解決辦法。 / In Taiwan, “Delicious Food” is well known world wide, and is one of the most proud of issue for Taiwanese. Small eats, and a lot of them, are the big things in Taiwan, and attracted a lot of tourists and brought a favorable income. Unfortunately, the Taiwan food scandal was started by the overuse one of plasticizer as a clouding agent in numerous food and beverage. It followed by “Toxic starch” and “Evil oil event”, which led to lose confidence and ruin administrative regulation of food safety to Taiwan government. Furthermore, there was a huge impact on Taiwan delicious food goodwill in the world. After uncovered each food scandal, Taiwan government tried to organize numerous food safety conferences, and has taken measures to restrain food safety regulation. In addition to food safety law revision, the penalty provision has been enhanced for unscrupulous vendors of food industry. However, food scandal is keeping on going, and the events are increasing in numbers these years. The food manufacturing and refining processes has become more evil. It means that food safety administrative regulation is run out of order, and the traditional law enforcement has faced the difficulty in this changing era. Since June 2013, food safety law revision included the brand new “Risk Analysis” model into “Precautionary Principle” concept. Risk analysis started over by European Union (EU), which is a politico-economic union of 28 member states that are located primarily in Europe. “Risk Analysis” model has three components, including risk evaluation, risk management and risk communication. In Taiwan, we have already taken “Risk Analysis” model on board for the innovation of food safety regulation, but Food Safety Law focused in the accounting system design of risk evaluation. There is only few in the risk management, and no statements in risk communication. Two years after food safety law revision, we still found the administration office has difficulty in facing the new food scandal, and the general populations are still worry about food safety issue. In order to reform the traditional law enforcement in food safety, the Act Governing Food Safety and Sanitation Taiwan included the risk analysis model first. Furthermore, in Taiwan’s food safety regime, the three-tier quality control system refers to self-management by food businesses, testing by independent institutions, and inspections by the government. It means that public-private partnerships (PPP) and self-regulation become a part of new regulation system. Through the cooperation between Taiwan Food and Drug Administration (TFDA) and private industrial association, the professionalism and efficiency of food safety regulation will be enhanced, but this kind of cooperation might be become the reasons of shirking the responsibility of government. Further investigation is mandatory.

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