Coffee grown in the United States represents less than 1% of the world's supply, and most of it comes from the state of Hawai'i. Kona coffee, grown on the western side of the island of Hawai'i, is the most recognized and the highest value Hawaiian coffee. The majority of this coffee is sun-dried after harvest and washing. Sun-dried coffee should reach 12-13% moisture within 4 to 6 days. Sun-drying will reduce both the moisture content and the water activity (aw). Reducing aw below 0.75, especially in the first week of drying, is important for preventing or limiting mold growth. The purpose of this study was to 1) compare drying rates of Kona coffee bean batches using aw and moisture content % measurements, 2) evaluate factors affecting the drying time of sun-dried Kona coffee, and 3) provide recommendations for post-harvest processing of sun-dried Kona coffee to optimize quality and safety. Ten farms in the Kona coffee region of Hawai'i were visited in the fall of 2017 to record data on the drying rate of coffee bean batches and to record observations on the post-harvest handling and storage of coffee beans and the environmental conditions that may affect the quality and microbial contamination of drying coffee. The coffee drying surfaces, physical enclosures, fan use, and elevation varied among farms. Daily measurements of coffee moisture level, water activity, depth of bean layer and temperature were recorded along with air temperature, relative humidity and cloud cover during drying for 30 batches. Most sun-dried batches reached 13% moisture in 6 to 10 days. Initial moisture content (31.6 4.3%), and drying yard characteristics varied greatly among farms. Coffee batches reached 0.75 aw within 6 days on average, but some batches required more than 10 days. Moisture content and aw measurements were weakly correlated and water activity level increased at times during drying for some batches. Allowing airflow around drying beans and maintaining a bean layer depth of less than 5 cm appeared to improve drying rates. Drying coffee parchments within 7 days post-harvest can inhibit growth of molds that may impact quality or molds that could produce mycotoxin. Controlling the drying conditions, including raking the layered beans, and monitoring moisture content can accelerate, or improve the consistency of, batch drying time. / Doctor of Philosophy / Coffee grown in the United States represents less than 1% of the world’s supply, and most of it comes from the state of Hawai’i. Kona coffee, grown on the western side of the island of Hawai’i, is the most recognized and the highest value Hawaiian coffee. The majority of this coffee is sun-dried after harvest and washing. Sun-dried coffee should reach 12-13% moisture within 4 to 6 days. Sun-drying will reduce both the moisture content and the water activity (aw*). (*Water activity is the measurement of water vapor pressure generated by the free or non-chemically bound water in foods and other products. Water activity (range of 0 to 1) is an important indicator for the shelf life of foods and the occurrence and growth of microorganisms). Reducing aw below 0.75, especially in the first week of drying, is important for preventing or limiting mold growth. The purpose of this study was to 1) compare drying rates of Kona coffee bean batches using aw and moisture content % measurements, 2) evaluate factors affecting the drying time of sun-dried Kona coffee, and 3) provide recommendations for post-harvest processing of sun-dried Kona coffee to optimize quality and safety. Ten farms in the Kona coffee region of Hawai’i were visited in the fall of 2017 to record data on the drying rate of coffee bean batches and to record observations on the post-harvest handling and storage of coffee beans and the environmental conditions that may affect the quality and microbial contamination of drying coffee. The coffee drying surfaces, physical enclosures, fan use, and elevation varied among farms. Daily measurements of coffee moisture level, water activity, depth of bean layer and temperature were recorded along with air temperature, relative humidity and cloud cover during drying for 30 batches. Most sun-dried batches reached 13% moisture in 6 to 10 days. Initial moisture content (27 to 36 %), and drying yard characteristics varied greatly among farms. Coffee batches reached 0.75 aw within 6 days on average, but some batches required more than 10 days. Moisture content and aw measurements were weakly correlated and water activity level increased at times during drying for some batches. Allowing airflow around drying beans and maintaining a bean layer depth of less than 5 cm appeared to improve drying rates. Drying coffee parchments within 7 days post-harvest can inhibit growth of molds that may impact quality or molds that could produce mycotoxin. Controlling the drying conditions, including raking the layered beans, and monitoring moisture content can accelerate, or improve the consistency of, batch drying time.

The demand for biodegradable packaging materials as an alternative to synthetic ones to reduce environmental cost has seen an increase in recent years. In addition, functionalizing the packaging film to provide specific advantages like antimicrobial properties has yet to be explored thoroughly. This study considers adding antimicrobial agents to improve the quality and safety of actively packaged fresh produce using an antimicrobial enzyme (lysozyme) immobilized on a biopolymer based packaging film (corn-zein). The developed packaging material is aimed as an active biodegradable packaging to reduce bacterial contamination on the surface of fresh organic produce, specifically tomatoes. The study uses glutaraldehyde and glyoxal as binding agents to immobilize the enzyme on the packaging film. The effect of concentration of glutaraldehyde and glyoxal on the controlled release of the enzyme was studied. Concentrations of 0.1 and 0.2 g/g lysozyme: cross linking agent had controlled release properties. However, concentrations of 0 or 0.05 are about 20-30% more effective at inactivating bacteria. Antimicrobial activity in the constructed zein films are also tested against selected pathogens (Salmonella Newport and Listeria monocytogenes). Developed zein based film is tested against inoculated tomatoes to determine the efficacy of the films in reducing the pathogen population. The inoculated tomatoes are stored at room temperature over a storage period of one week. The film was able to reduce Listeria monocytogenes population by three logs but was unable to reduce the population of Salmonella Newport. / Master of Science

Risk analysis is a powerful science-based tool that can be used to control and mitigate microbial food safety hazards. Codex recommends conducting preliminary risk management activities (PRMAs) to initiate risk analysis and to plan the risk assessment process. The information learned from these PRMAs should be utilized to construct a quantitative microbial risk assessment (QMRA) model. Then, risk management activities can utilize the QMRA model to identify and select microbial risk management (MRM) options. In this project, Codex recommendations for conducting risk analysis were followed to analyze the risk of acquiring salmonellosis from whole broiler (meat chickens) consumption within the United States. At the first stage, the risk of Salmonella on whole broilers was quantitatively estimated by attributing reported annual salmonellosis to whole broilers. A quantitative microbial risk assessment (QMRA) model was constructed to build an informative risk analysis model based on performance criteria, while minimizing associated modeling complications. The QMRA model was constructed in Excel® (Microsoft Corporation, Redmond, WA, USA) with the @RISK® Add-ins software (Palisade Corp., Ithaca, NY, USA). @RISK® software was used to perform Monte Carlo simulations that account for attendant uncertainties. After the model was tested and calibrated, it estimated the annual salmonellosis cases from whole broilers as 216,408 case/year that corresponds to the number of salmonellosis reported by Center for Disease and Control Prevention (CDC). Furthermore, sensitivity analysis was performed where 16 sensitive inputs (potential places for food safety interventions) and 10 data gaps (inputs that significantly affect the overall uncertainty) were reported. Some QMRA model results were transformed to MRM metrics. These MRM metrics, including ALOPs (Appropriate Level of Protection), FSOs (Food Safety Objectives), POs (Performance Objectives), and PC (Performance Criteria), were calculated along with a sampling plan for a food safety control system. The MRM metrics were utilized to identify and plan food control interventions such as risk communication, auditing, inspection, and monitoring. Furthermore, the QMRA model was utilized to identify and to quantitatively evaluate food safety interventions that affect Salmonella prevalence and/or concentration. / Ph. D.

Consumers desire tender, juicy, and flavorful cuts of beef. Mechanical tenderization (MT) and enhancement methods applied to lower valued beef cuts can improve tenderness, flavor or juiciness, increasing desirability for the consumer. However, these processes can introduce pathogens that may be present on the exterior of the meat into the sterile interior. This process renders an ‘intact’ product ‘non-intact’ and requires altered cooking methods to ensure safety. The primary pathogens of concern for beef products are Shiga-toxin producing Escherichia coli (STEC). STEC are associated with approximately 265,000 illnesses and 3,600 hospitalizations annually. Since 2006, there have been 6 STEC outbreaks in the United States and 18 cases in Canada attributed to MT beef (MTB). The pathogen has also been implicated in 136 non-intact beef-related recalls. Due to the potential food safety hazards associated with MTB, mandatory labeling of these products was mandated in 2015 to inform consumers on how to safely handle the product. While this is a good step to inform consumers, it is unclear how familiar they are with the terms associated with these processes. Consumer’s knowledge, beliefs, attitudes, awareness, and behaviors related to MTBs is quite limited. This study uses an exploratory sequential mixed-methods design, to assess consumer knowledge of MTB. Qualitative focus groups conducted throughout urban and rural North Carolina and Virginia found that although participants purchased MTBs, they were unaware of the process, did not prepare MTBs properly, wanted to know more about the process, and wanted applicable risk messages. A nationwide survey developed from the focus group findings found that demographic differences were associated with knowledge of; and how participants interact with MTBs. How demographics influence consumer’s beef safety knowledge, practices, and risky behaviors was further explored. Demographic characteristics were highly correlated with consumers’ behaviors surrounding beef storage, refrigerator temperature knowledge, defrosting behaviors, meat washing, and meat preparation behaviors. Collectively, the mixed methods research design provided insight into specific demographic characteristics related to consumer attitudes, beliefs, and behaviors surrounding beef safety. This data will help inform the development of well-crafted, culturally, and socially relevant risk messaging that may promote safe handling behaviors. / Ph. D. / In the United States, every year, the Center for Disease Control estimates that 48M people are sickened, 128,000 people are hospitalized, and 3,000 people die from foodborne illnesses. The most common illnesses arise from Salmonella, Norovirus, Campylobacter, Escherichia coli [E. coli], Listeria, and Clostridium perfringens; these bacteria and viruses have been on the news as being associated with flour recalls, cantaloupe, eggs, cheeses, berries, and even at restaurants like Chipotle! The bacteria of concern in this study is E. coli. Most E. coli is not pathogenic, and extremely common in the environment; living in mammalian (e.g. humans, cows, sheep, insects, etc.) gut and within the environment (e.g. in the soil). However, there are some pathogenic variants, like Shiga-toxin producing E. coli [STEC] that have been associated with 265,000 annual illnesses and deaths. The main reservoirs of many pathogenic E. coli are within the intestines of ruminant mammals, including cattle. If mishandled, feces can contaminate and cause human illness as a result of improper handling and preparation. The contamination can occur through meat, water, and fecal-oral routes; often, improperly cooking and handling beef products can lead to illness. In the U.S., there have been 27 multi-state STEC associated food outbreaks. While the U.S. beef industry is the largest in the world, five multi-state outbreaks were related to E. coli O157:H7 contamination in ground beef products. Additionally, between 2005 – 2018, 136 of 171 recalls were due to STEC-contaminated beef products. Non-intact beef products (e.g. ground beef) are the most commonly recalled types of beef products. Consumers purchase beef products on extrinsic (i.e. price, weight, cut) and intrinsic (i.e. color, fat, safety) factors with a desire for tenderness, juiciness, and flavor. Tenderization processes (e.g. mechanical tenderization) or other enhancement processes (e.g. marinades) can increase tenderness on lower-value cuts but may introduce pathogens from the exterior to the sterile interior. To prevent illness, it is necessary to prepare beef products to the recommended USDA-specified temperature using a thermometer to check. Up until this point, consumer knowledge of and behaviors towards mechanically tenderized beef products [MTB]s and other enhanced beef products had not been characterized. This study uses an exploratory sequential mixed-methods study design (qualitative study guides quantitative study) to assess consumer knowledge of MTBs, enhanced beef products, and food safety / beef safety handling behaviors. Focus groups conducted throughout urban and rural North Carolina and Virginia found that although participants purchased MTBs, they were unaware of the process, did not prepare them properly, wanted to know more about MTBs, and requested different ways of obtaining information. A nationwide survey developed from the focus group findings found that demographic differences were associated with knowledge of and interaction with MTBs and enhanced beef products. However, people were still generally unaware of MTBs, despite a recent 2016 labeling mandate for all MTBs. The Theory of Planned Behavior was used to further explore reported consumer’s food safety knowledge, practices, and risky behaviors in the kitchen. Demographic characteristics were highly correlated with consumers’ behaviors of beef storage, refrigerator temperature knowledge, defrosting behaviors, meat washing, and meat preparation behaviors. Collectively, the mixed methods research design provided insight into specific demographic characteristics related to consumer attitudes, beliefs, and behaviors surrounding beef safety. Additional research, alternative non-didactic strategies, and collaborations within health and public services is necessary to accommodate for specific demographics, cultures, and social groups. Well-crafted, culturally, and socially relevant targeted risk messaging must be developed to increase awareness and promote ease-of-access.

The pathogenic microorganism Salmonella enterica has been associated with several outbreaks and recalls of spices, herbs, and seeds. To control these pathogens additional treatment methods, such as fumigation with chlorine dioxide (ClO2) or hydrogen peroxide (H2O2) gas and recovery methods are needed. Recovery methods should accurately quantify all viable cells, even those injured, to prevent overestimation of treatment effectiveness. This study was performed to determine the effect of different recovery media and supplements on the recovery of multiple strains of S. enterica and Enterococcus faecium NRRL B2354, from chlorine dioxide or hydrogen peroxide treated low moisture foods (LMF) black peppercorns, dried basil leaves, and chia seeds. Also, this study aimed to compare the log reduction of these two microorganisms to evaluate E. faecium NRRL B2354 as a surrogate for S. enterica. On average, recovery of S. enterica was 3.43 log and 4.77 log CFU/g from ClO2 and H2O2 treated LMFs, respectively on the selective media Xylose Lysine Deoxycholate agar, while the average recovery on non-selective media was 4.50 log CFU/g and 5.74 log CFU/g from ClO2 and H2O2 treated LMFs, respectively. The use of non-selective media was correlated with increased recovery compared to selective media. In further studies, addition of sodium pyruvate, ferrous sulfate, or 3'3'-thiodiproionate supplements to MTSAYE did not show increased recovery (P>0.05). On each treatment and LMF combination tested, there was no significant difference between the log reduction of S. enterica and E. faecium NRRL B2354, indicating its suitability as a surrogate under the test conditions. / Master of Science in Life Sciences / Spices, dried herbs, and seeds have become popular throughout the world for enhancing the flavor of food, but may also harbor harmful bacteria, including Salmonella enterica. It is US federal law under the Food Safety Modernization Act that these foods are safe to eat straight from processors since these foods are typically consumed raw. Novel treatment methods are being tested to kill harmful bacteria on these dried foods without adding water including chlorine dioxide fumigation and hydrogen peroxide fumigation. However, these processes can injure the bacteria without killing them. These injured bacteria might not be counted using traditional means which could lead to overestimating the effectiveness of a treatment. Different media types, used as part of the process to count the number of bacteria in a sample, were tested to determine their effect on recovery of injured S. enterica cells. Furthermore, the bacterium Enterococcus faecium NRRL B2354 was tested against S. enterica to evaluate, if the former, a relatively harmless microorganism, could be used by food processing plants to determine that their treatment processes meets regulatory standards. More injured S. enterica cells were recovered from each non-selective media tested, compared to the selective media. Although there isn't a significant difference in injured S. enterica recovery between any supplemented non-selective media, any non-selective media recovers more sub-lethally injured cells, and would give more accurate bacterial counts. Results also indicated that E. faecium NRRL B2354 is a suitable surrogate to the pathogen S. enterica for spices and herbs processed under the same conditions.

<p dir="ltr">The increasing consumption of fresh produce such as cantaloupes, watermelons, lettuce, and cucumbers has been linked to multiple foodborne outbreaks, highlighting the urgency of implementing effective measures to prevent bacterial contamination, colonization, and internalization. This study evaluates various antimicrobial chemical washing solutions to reduce foodborne pathogens and improve the microbial quality of fresh produce. The research investigates the impact of netting density on cantaloupe rind surfaces and assesses the efficacy of sodium hypochlorite (FAC), peracetic acid (PAA), and chlorine dioxide (ClO₂) against <i>Escherichia coli</i>, <i>Listeria monocytogenes</i>, and <i>Salmonella </i>Typhimurium. Results suggest that higher netting densities decreased the efficacy of these treatments, with smooth rind cantaloupes showing the highest bacterial reduction when treated with PAA and FAC. Further investigations into the inline application of antimicrobial washing solutions under commercial packing house conditions revealed that combining ClO₂ and PAA significantly reduced pathogen loads on cantaloupes and watermelons without adversely affecting their sensory qualities. Additionally, the study assessed the effectiveness of PAA, FAC, and accelerated hydrogen peroxide (AHP) on fresh cucumbers, broccoli, and lettuce under conditions that emulate commercial retail facilities. The treatments achieved significant log reductions in aerobic mesophilic bacteria and common pathogens, highlighting the critical role of these solutions in preventing cross-contamination during postharvest handling. Finally, the research also examined the internalization of foodborne pathogens in lettuce and cucumber plants, revealing high recovery rates of <i>E.</i><i> </i><i>coli </i>O157:O157H7 and <i>S.</i><i> </i>Typhimurium from contaminated seeds, soil, leaves, and blossoms. These findings highlight the potential for pathogen colonization and persistence in fresh produce, indicating the need for preventative agricultural practices and microbial control measures throughout the cultivation and handling processes. Together, these studies suggest that integrating effective antimicrobial washing solutions with proper storage conditions and good agricultural practices is essential for enhancing fresh produce's microbial safety and shelf-life, thereby reducing the risk of foodborne illnesses.</p>

<p dir="ltr">From farm to fork, every player in the food supply chain bears responsibility for ensuring food safety standards are met. Food safety educators are a key component in addressing knowledge and behavior gaps amongst the different players. Conducting a needs assessment allows educators to appropriately design a food safety education program for its target population. Three case studies are presented in this thesis, each investigating the food safety perceptions and needs of different target populations through a needs assessment. Each case study had two objectives: 1) identify food safety education needs for a specific target population; and 2) provide specific food safety education recommendations to address identified needs. The overall objective of this thesis was to uncover the food safety relationships between the different players in the food supply chain. The first case study (Ch. 2) examines consumers’ preferences for food safety through a national online survey. The study conclusively demonstrates consumers’ discernible preference for produce with food safety labels, however reflecting a willingness to pay only a small premium for such products. Indicating an increased price to consumer may not be an appropriate incentive in motivating farmers to adopt food safety practices. The second case study (Ch. 3) examined military veteran farmers’ on-farm food safety perceptions, knowledge, and behaviors through a national survey and in-person interviews. Military veteran farmers are aware of the importance of food safety; however, they reported risky on-farm food safety behaviors. Furthermore, military veteran farmers' unique needs were uncovered, which could help educators tailor resources for this niche farmer group. The third case study (Ch. 4) examined small- size produce drying processors’ food safety needs from the perspective of the inspector through interviews. The study demonstrated a need for clarity on the regulations and food safety standards for the small- size produce drying process. In summary, this thesis demonstrates the need for tailored food safety education interventions to meet the specific expectations of small-size and niche players in the food supply chain. Future work is recommended to continue exploring the food safety needs of niche players in the food supply chain and providing tailored food safety programs.</p>

<p dir="ltr">The following dissertation contains a series of articles from a diverse set of research experiences over my five years as a PhD student at Purdue University. Each of the following articles relay how my interdisciplinary studies in food safety, gender, and higher education contribute to a comprehensive understanding of international development in agriculture. After an introductory chapter, chapters two and three include systematic literature review articles on the state of food safety in Lao PDR and Cambodia. Each review discusses available knowledge and potential development opportunities surrounding food safety, a significant threat to public health, especially in low- and middle-income countries. Building upon the food safety literature, chapters four and five are based upon research aimed at reducing foodborne illnesses in Cambodia’s informal vegetable value chain. Toward this end, the chapters present two articles that study the lives of Cambodian women vegetable producers to inform future food safety engagement. The final three chapters are a collection of articles based on my experiences working with agricultural higher education in international development contexts. Chapters six and seven present two articles about the employability of Egyptian agriculture university graduates. Chapter eight includes my final research article and explores how a service learning-based study abroad in Romania encouraged agricultural engagement interest and skills in undergraduate agricultural students. Lastly, chapter nine concludes the dissertation with final remarks and reflections about how each discipline provided a different perspective to international development in agriculture, and the value of applying interdisciplinary approaches to complex challenges.</p>

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Die Lebensmittelsicherheit hat in der türkischen Agrar- und Ernährungswirtschaft in den letzten Jahren erheblich an Bedeutung gewonnen. Dies ist vor allem der Tatsache geschuldet, nach dem die Türkei im Jahr 2005 als Beitrittskandidat der Europäischen Union (EU) akkreditiert wurde, denn die EU ist mit Abstand der wichtigste Handelspartner der Türkei für Agrarprodukte. Die Türkei hat im Jahre 2012 einen Handelsüberschuss im Agrarsektor von 3,6 Mrd. allein Euro mit den EU-27 Ländern erwirtschaftet (Eurostat, 2013). Das Dissertationsprojekt befasst sich im Rahmen einer empirischen Untersuchung mit den Zertifizierungssystemen im türkischen Agribusiness und es wurde insbesondere untersucht, welche Einflussgrößen auf die Zertifizierungsentscheidungen in der türkischen Agrar- und Ernährungswirtschaft existieren. Dazu wurden anhand einer Online-Befragung Daten von weiterverarbeitenden Betrieben gesammelt und für weite Teile der Türkei systematisiert. Überdies wurden sieben persönliche Interviews in ebensolchen Unternehmen durchgeführt sowie Experten aus dem türkischen Ministerium für Landwirtschaft sowie dem EU-Ministerium zum Thema Zertifizierungssysteme befragt. Da die Türkei Nettoexporteur von Agrarprodukten ist, wird dieser eine entschiedene Einfluss auf die künftige internationale Wettbewerbsfähigkeit ihrer Agrar- und Ernährungswirtschaft allgemeinen zugerechnet.