Nutrition & Food Science
Permanent URI for this communityhttp://hdl.handle.net/1903/2267
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Item Determinants of Food Insecurity in the League of Arab States(2022) Sheikomar, Olfat Bakur; Sahyoun, Nadine R; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Background Food insecurity (FI) is widespread in the League of Arab States (LAS) due to factors including gender inequality, conflict, and political turmoil. However, limited data are available on its prevalence and determinants in that region. This dissertation aims to 1) validate the Food Insecurity Experience Scale (FIES), developed by the UN Food and Agriculture Organization, and assess the prevalence of FI in that region; 2) examine the association between FI, physical health, and mental well-being by sex and whether social support modifies this association in women; 3) examine the relationship between Palestinian live-in grandparents (GP) and the health and well-being of their grandchildren.Methods Rasch modeling was applied to the Gallup World Poll data to validate FIES in 19 countries of the region. Descriptive and logistic regression analyses were applied to data from 62,261 respondents aged 19 and over to examine determinants of FI. Logistic regression was also used to analyze the data of 2707 households and 8,034 children ages 0-17 from two surveys of Palestinian refugees. Results FIES met the Rasch assumptions indicating good internal validity. The prevalence of severe FI was 15.7% and women were at highest risk compared to men (17.6% vs. 14.1%, respectively, p<0.0001). Older age, living in rural areas, and high dependency ratio were associated with severe FI in women. High negative experience and low income were associated with severe FI, but good physical health and high positive experience with lower prevalence of severe FI. Having a live-in GP in the household was associated with grandchildren’s lower odds of experiencing an acute disease and higher odds of attending school. Conclusion FIES is a valid tool; however, cognitive testing of some items and omission of correlated ones may improve the scale. FI is highly prevalent and should be monitored to develop multi-sectoral intervention strategies. Mixed method studies are needed to better understand the relationship between grandparents and their grandchildren.Item Development of machine learning and advanced data analytical techniques to incorporate genomic data in predictive modeling for Salmonella enterica(2021) Karanth, Shraddha; Pradhan, Abani K; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The past few decades have seen a renaissance in the field of food safety, with the increasing usage of genomic data (e.g., whole genome sequencing (WGS)) in determining the cause of microbial foodborne illness, particularly for multi-serovar agents such as Salmonella enterica. However, utilizing such data in a preventative framework, specifically in the field of quantitative microbial risk assessment (QMRA) remains in its infancy, because incorporating such large-scale datasets in statistical models is hindered by the sheer number of variables/features introduced. Thus, the goal of this research is to introduce machine learning (ML)-based approaches to potentially incorporate WGS data in various stages of a risk assessment for Salmonella enterica. Specifically, we developed a machine learning-based workflow to obtain an association between gene presence/absence data from microbial whole genome sequences and severity of Salmonella-related health outcomes in host systems. A key contribution of this dissertation is assessing the applicability of Elastic Net model, a recursive feature selection technique, which resolves a well-known issue concerning WGS-based data analysis: variables/features outnumber the count of observations. Building on this finding, we developed a gene weighted Poisson regression method to incorporate genes into a dose-response framework for Salmonella enterica, thereby incorporating genetic variability directly into a risk assessment framework. Finally, we combined machine learning with count-based models to determine how significant genes interact with meteorological factors in impacting the severity of salmonellosis outbreaks. This dissertation uncovers some interesting findings. First, although commonly used classifiers (such as random forest) performed well in predicting disease severity, logistic regression, in conjunction with Elastic Net, performed significantly better. This finding is important, as the result of a logistic regression is generally more interpretable than that of other classifiers, easing its incorporation into predictive microbial modeling. Next, machine learning-supported count-based models, such as Poisson regression also proved to be a good fit for gene-informed dose-response modeling and determination of outbreak severity when combined with extrinsic factors such as atmospheric temperature and precipitation. Overall, this dissertation identified areas within a QMRA framework that could benefit from incorporating genetic information, and introduced ML models to incorporate such information.Item Food Insecurity, Service Awareness, Social Factors, and Quality of Life in Community-Dwelling Older Adults(2021) Vaudin, Anna Margaret; Sahyoun, Nadine R; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Older adults are at risk for food insecurity due to financial constraints, physical difficulties, social isolation, and the resulting limitations on food access. Social isolation has two components – objective, such as social contacts, and subjective, such as loneliness – and each may have a unique relationship with food insecurity. Unmet needs exist for services that aim to improve food access in older adults, and research is limited on how those who do use the services find out about them. Additionally, these services aim to improve quality of life (QOL), and yet this impact cannot be quantified because current tools do not capture the ways food affect QOL beyond nutritional status. This dissertation uses qualitative methods to understand (1) how food and eating impact QOL in community-dwelling older adults, (2) how individuals become aware of the services they use to address barriers to food and eating, and (3) the interaction between food security, loneliness, and QOL. In-depth interviews were conducted with 25 urban- and suburban-dwelling older adults. Interview scripts were transcribed and themes identified in the data using grounded theory methods. The first study showed that health and vitality, independence, mental and emotional well-being, socialization and support, and activities, both inside and outside the home, affected participants’ QOL. Food and eating affected QOL through access and choice, health and vitality, enjoyment of food, and food preparation. The second study showed that participants primarily found out about the resources they use through encounters in their daily lives, rather than service outreach. The final study showed that, compared with those who were food secure, those who were food insecure were more likely to report a negative effect of loneliness on their QOL, primarily experienced as depressive symptoms. This dissertation shows that food and eating affect older adults through not only the physiological effects of good nutrition, but also through social, psychological, and sensory effects on QOL. Additionally, the results point to the importance of social factors for both service awareness and mental health in those who face barriers to food and eating. Future studies and new tools are needed to quantify these impacts.Item DIET, FOOD SECURITY, SOCIAL RELATIONSHIPS AND DEPRESSIVE SYMPTOMS IN HOMEBOUND OLDER ADULTS IN THE UNITED STATES AND THEIR IMPACT ON HEALTHCARE UTILIZATION(2020) Ashour, Fayrouz A.; Sahyoun, Nadine R; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Homebound older adults may be at increased risk for malnutrition and social isolation, posing a potential threat to them aging in their communities and increasing healthcare cost. The Nutrition Service Program under Older Americans Act (OAANSP) was established to support older adults aging in place by delivering meals and providing nutrition-related services. Aims: 1) Examine diet quality of home-delivered meal (HDM) recipients; 2) examine direct and indirect associations between social relationships, depressive symptoms, food insecurity (FI) and diet quality; and 3) examine direct and indirect associations between social relationships, FI, diet quality and hospitalization. Methods: Data obtained from OAANSP Outcomes Evaluation study included: 1) client outcomes survey, 2) two 24-hour dietary recalls, and 3) Medicare healthcare utilization data. Dietary recalls examined diet quality by calculating 1) population-level mean HEI scores; and 2) usual vegetable and protein intakes. Diet quantity was compared to Dietary Guidelines for Americans 2010 (DGA), and structural equation modeling was used to examine direct and indirect relationships. Results: HDM recipients and controls have high prevalence of FI, 22.4% and 16.5%, respectively. HDM recipients who did not receive a meal on day of dietary recall (no-meal recipients) had significantly poorer diet quality than HDM recipients who received a meal (meal recipients) that day and control group. Quality of overall diet for meal recipients, no-meal recipients and controls did not meet recommendations for several food groups/nutrients. Compared to DGA, HDM and complementary foods were low in whole grains, dairy, fiber, and surpassed upper limit of consumption for saturated fats, refined grains, sodium and added sugar. High FI was associated with greater depressive symptoms and lower usual vegetable intake in control group. High FI was associated with lower usual protein intake in HDM recipients and controls. Both groups were at high risk for protein insufficiency, which was associated with greater hospitalization in the control group. Conclusions: HDM recipients and controls have high prevalence of FI, poor diet quality, and insufficient protein intake. Increasing funding for OAANSP can allow program expansion and improvement of HDM. Validated tools to examine social relationships and additional contributors to FI are neededItem USE OF RISK ASSESSMENT MODELING TECHNIQUES TO DEVELOP QUANTITATIVE RISK-BASED HAZARD ANALYSIS AND CRITICAL CONTROL POINT (RB-HACCP) PLANS(2017) Williams, Elizabeth Noelia; Buchanan, Robert L; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Hazard Analysis and Critical Control Point (HACCP) is the internationally recognized system to assure the safety of food products and the foundation of food safety programs worldwide. However, its success is limited by its inability to relate stringency to measurable public health impacts and its inherent qualitative nature. The aim of this research was to incorporate quantitative microbiological risk assessment (QMRA) techniques into HACCP to develop risk-based HACCP (RB-HACCP) plans. The research hypothesized that the Critical Control Points (CCPs) are steps in the process that significantly reduce the mean and/or variance of a hazard and that these can be identified and quantified using risk assessment modeling techniques such as sensitivity analysis (SA) and what-if scenario analysis, as well as providing a more objective means in considering Critical Limits (CLs). QMRA models were developed for two distinctly different commercial food products, frankfurters and cold-smoked salmon (CSS). The former has a definitive inactivation step while the latter achieves control through a series of partial control steps. Modular Product Pathogen Pathway risk assessment models were developed to identify potential risk-based CCPs (RB-CCPs) for the control of Listeria monocytogenes. Steps of the processes within modules were evaluated and prioritized using SA to determine the relative contribution of the process steps to control L. monocytogenes. What-if scenario analyses were subsequently used to quantitatively determine the consequences of system deviations, thereby allowing risk-based CLs (RB-CLs) to be set and the most-effective risk mitigation strategies to be identified. This conceptual framework, combined with relevant plant-specific data, was used to identify RB-CCPs and RB-CLs, thereby producing RB-HACCP plans that are linked with public health goals to lower the risk of listeriosis. This allowed a direct comparison between current industry HACCP plans for frankfurters and CSS with RB-HACCP plans derived from the risk assessments. The comparison suggests that the use of RB-HACCP plans may offer advantages in developing the “preventive controls” risk management food safety plans required under the FDA Food Safety Modernization Act of 2011.Item Formative research regarding social support programs and young adults living with type one diabetes(2015) Brady, Patrick James; Song, Hee-Jung; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Little research has been conducted regarding social support programs (SSPs) for young adults with Type 1 Diabetes Mellitus (T1DM). Formative research was conducted including: in-depth interviews with individuals who have organized or lead SSPs, a survey of young adults with T1DM, and forming a community advisory board to develop themes and discussion points for a SSP. Eight interviews were conducted. The perceived benefits of and barriers to attending a SSP, the perceived barriers to managing a SSP, and topics important for young adults were described. 38 individuals completed the survey and were included in the analysis. The survey identified ever attended a SSP as significant in the perception of tangible and affectionate support. Two CAB meetings resulted in six themes and discussion points to be used as a framework for a proposed SSP. This study suggests the benefit of SSPs for young adults and provides insight into the role of SSPs in managing T1DM.Item Electronic Interventions to Improve Health Behaviors in College Students(2014) Schweitzer, Amy; Lei, David K.Y.; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Introduction: In transitioning from adolescence to adulthood, college students are faced with significant challenges to their health habits. Time, independence and stress have been known to result in poor eating and exercise habits which can lead to increased disease risk. Objective: To assess whether an electronic health intervention can improve health habits in college students. Methods: A 24-week diet and physical activity program was delivered by e-mail to 148 college students. The intervention involved weekly tailored, interactive diet and physical activity goals. The control group received non-diet-non-exercise-related health fact sheets. Baseline, 12-week, and 24-week diet and physical activity surveys were completed online. BMI, neck circumference, waist circumference, and percent fat mass (FM%) by bioelectrical impedance analysis were measured at baseline, week 12 and week 24. Results: Students were 18-20 years old 70% female from a diverse college campus (46% Caucasian, 23% Asian, 20% African American, 5% Hispanic, and 6% other). At baseline, 23% were overweight/obese by BMI, 88% reported consuming <5 fruits and vegetables daily, 59% consumed >10% of kcalories from saturated fat, although 91% met or exceeded 150 minutes/week of moderate-vigorous exercise. Seventy-one percent of students completed all study visits. Repeated measures ANOVA showed a significant treatment by linear time interaction for saturated fat. A significant change from baseline saturated fat intake was detected between the treatment groups at week 24 (mean change ± standard error 0.7±0.42% of kcal for control and -0.3±0.30% of kcal for intervention). Differences in saturated fat intake between the two treatment groups were more evident in those whose intake exceeded recommendations. BMI, neck circumference, waist circumference, FM%, weekly minutes of moderate and vigorous physical activity as well as intake of fruit, vegetables, and added sugar were not significantly different between treatment groups. Conclusion: College students enrolled in an interactive electronic health intervention decreased saturated fat intake compared to control. Furthermore, the decrease observed in the intervention group was mainly due to those whose intake of saturated fat intake was above the recommended 10% of total kcalories. Further development of the electronic intervention program is needed to maximize health benefits in college students.Item ASSESSMENT OF PREHARVEST MICROBIAL QUALITY OF CANTALOUPES AND PUBLIC HEALTH RISKS ASSOCIATED WITH CANTALOUPES CONTAMINATED WITH LISTERIA MONOCYTOGENES(2014) Wang, Miao; Pradhan, Abani K; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Cantaloupe has been recognized as a common vehicle for foodborne infections among fresh produce commodities. A severe multistate outbreak of Listeria monocytogenes associated with the consumption of whole cantaloupe resulted in 33 deaths in 2011. Quantitative microbial risk assessment (QMRA) modeling in food safety risk analysis has been acknowledged as an efficient tool to estimate and provide knowledge needed to manage potential public health risks associated with foodborne pathogens. The objectives of this study were to (i) conduct a microbiological survey of pre-harvest cantaloupes from farms in mid-Atlantic region, and (ii) develop a "farm to table" QMRA model for L. monocytogenes in cantaloupe. The results of the regional microbiological survey indicated a 5.3% (2/38) prevalence of generic Escherichia coli and negative for L. monocytogenes and Salmonella on cantaloupe during harvest season. A QMRA model was developed based on a thorough review of data from scientific publications and communications with fresh-cut processing industry. The model was simulated with Monte Carlo technique for 100,000 iterations in @Risk. The model estimated the public health risks associated with the consumption of both fresh-cut and whole cantaloupes in the U.S. The model demonstrated the risk associated with the consumption of a serving of fresh-cut cantaloupe is around 10 times higher than that for whole cantaloupe. Using the baseline model, the estimated median number of listeriosis cases per year associated with the consumption of fresh-cut cantaloupe among susceptible subpopulation and general healthy population are 0.0368 and 0.00134, respectively. Sensitivity analysis suggested temperature control during retail (correlation coefficient: 0.69) and home storage (correlation coefficient: 0.48) are two critical factors in mitigating the risk for fresh-cut cantaloupe consumption while home storage temperature (correlation coefficient: 0.79) after cutting is the most important factor for whole cantaloupe consumption. The QMRA model provided critical information for risk management and identified the critical data gaps including initial contamination and prevalence for future risk assessments of melon.Item The Role of Organic Matrices (dried turkey manure) in the Contamination and Survival of Salmonella spp. on Baby Spinach Leaves(2012) Oni, Ruth Adeola; Buchanan, Robert L; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Microbiological safety of fresh produce has attracted attention due to constant produce outbreaks. Manure contaminated with enteric pathogens has been identified as a major pre-harvest contamination source. This study investigated the survival of Salmonella in dust particles generated from dehydrated turkey manure, and how this could serve as an airborne contamination of leafy greens. Laboratory trials of the UV resistance of Salmonella in manure dust were also conducted to assess its protective effect; along with greenhouse studies to determine the survival of Salmonella in manure dust on spinach leaves. Results indicate survival times were inversely related to moisture content and particle size of manure dust. The presence of manure particles substantially enhanced the pathogen's survival under UV and reduced its inactivation on spinach leaves. This study presents data that could be used to assess the potential role of aerosolized manure as a pre-harvest risk factor for contamination of leafy greens.