Browsing by Author "Boyer, Renee Raiden"
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- Assessment of Farmers Market Practices and Characteristics to Inform the Development of Tailored Educational MaterialsDuong, Minh Dao (Virginia Tech, 2021-09-21)Farmers markets (FM) have become increasingly popular almost tripling over the past two decades due to the rising interest in local and/or organic foods. Within this same time period, notable farmers market foodborne illness outbreaks; such as E. coli O157:H7 and strawberries and Salmonella and peas; have occurred, and emphasize the importance of food safety practices at farmers markets. Some farmers may be encouraged to follow Good Agricultural Practices (GAPs) to limit the contamination of fresh produce; however, GAPs programs are complex and also very driven by wholesale buyers. Furthermore, many FM growers are unfamiliar with GAPs or do not believe it is applicable to them. The Food Safety Modernization Act (FSMA) was passed in 2011, and shifted the food safety paradigm from a reactive to proactive approach introducing seven different rules including the Preventive Controls for Human Foods (PCHFR) and the Produce Safety Rule (PSR). Each FSMA rule does contain exemptions for smaller-scale operations (e.g., farms, facilities) that allows them to be excluded from the rule, or excluded from certain aspects of the rule. Generally, most FM vendors may satisfy exemptions from the FSMA regulations (e.g., be exempt from the FSMA Produce Safety Rule because of commodities); however, to our knowledge, no studies have assessed the regulatory compliance requirements of FM vendors to the FSMA regulations. This dissertation explored the regulatory requirements of FM vendors, and the accessibility of FSMA materials for these audiences. Additionally, due to the sudden and unprecedented global COVID-19 pandemic, an objective was added that explored how COVID-19 influenced behavior changes among this audience. Interviews were conducted and found that all vendors (100%) were exempt from the PCHFR and that most vendors (67%) were exempt from the PSR, some were qualified exempt (28%), and a few (5%) were covered. This study also found that farmers market vendors received information mainly from University Cooperative Extension sources. The COVID-19 pandemic greatly impacted hygiene and health practices at FMs. Market personnel (managers and vendors) implemented many different hygiene and health practices at their markets. The major source of COVID-19 food safety information for market personnel was local and federal government; as well as University Cooperative Extension. Accessibility analyses showed that many FM or COVID-19 resources were not accessible due to populations that rely on produce safety resources generated by Cooperative Extension due to (i) navigation or web accessibility errors, (ii) high literacy level requirements, and (iii) lack of keep (i.e., resources were not up-to-date, or continuously managed or monitored). These findings will inform the development of FM targeted resources, that are also, accessible to a more diverse and inclusive audience. One example is a produce safety resource on the updated agricultural water requirements that is developed to an 8th grade reading level, with no broken links or additional navigations errors, and if a PDF version is available, proper headers and titles.
- Evaluating Risks and Mitigation Measures for Foodborne Pathogens on Harvest BagsAyuk Etaka, Cyril Nsom (Virginia Tech, 2024-06-07)Tree fruit growers need information on pathogen dynamics following harvest bags contamination to determine effective sanitation interventions for decontaminating these surfaces. Therefore, the objectives of this research were (i) to determine the survival of generic E. coli, Salmonella, and L. monocytogenes on different harvest bag materials (ii) to quantify the transfer of generic E. coli, Salmonella, and L. monocytogenes from different harvest bag materials to fresh unwaxed apples and (iii) to determine the efficacy of different sanitizers for decontaminating different harvest bag materials. For Obj. 1, harvest bag materials were inoculated with rifampicin-resistant (80ppm; R) E. coli (TVS353) or Salmonella strain cocktail or L. monocytogenes strain cocktail. All surfaces were air-dried and held at 22 °C and either 30 or 80% relative humidity for 90 d (E. coli), or at 22 °C and 55% relative humidity (RH) for 21 d (L. monocytogenes and Salmonella). For Obj. 2, harvest bag materials were inoculated with E. coli (TVS353) or Salmonella strain cocktail or L. monocytogenes strain cocktail and air dried as previously mentioned. For E. coli trials, bacterial transfer to unwaxed 'Red Delicious' apples was assessed for 2 inoculum dry times (1 or 4 h), 2 contact times (5 or 25 minutes), and 2 pressure scenarios (0.0 or 0.1kg/cm2). For Salmonella or L. monocytogenes trials, transfer was assessed for 1 inoculum dry time (1 h), and 1 contact time (5 minutes). For Obj. 3, coupons were inoculated with L. monocytogenes or Salmonella cocktails and were air-dried. Following inoculation, coupons were exposed to different sanitizer treatments: chlorine, peroxyacetic acid (PAA), isopropyl alcohol with quaternary ammonium compounds (IPAQuats), steam, and water. Regression models were fitted, and Tukey's post hoc test was performed at P<0.05. E. coli exhibited survival for extended durations at 30 % than at 80% RH. In addition, E. coli survived at higher concentrations on canvas surfaces than on cordura and nylon surfaces. Generally, E. coli survived for more than 21 d across all surfaces and exhibited a triphasic die-off pattern. Similarly, L. monocytogenes and Salmonella exhibited die-off in phases with an initial rapid die-off followed by more gradual die-off rates up to 21 d. Canvas materials also promoted better L. monocytogenes and Salmonella survival than cordura surfaces. Contact time did not significantly impact the transfer of E. coli from harvest bag surfaces to apples (P=0.55). However, pressure, inoculum dry time and material type significantly impacted the transfer of E. coli to 'Red Delicious' apples (P≤0.03). The transfer rates of Salmonella did not differ between canvas and cordura surfaces (P=0.46). However, cordura transferred L. monocytogenes at significantly higher rates than canvas surfaces (P<0.001). Of the sanitizer treatments that were used on L. monocytogenes or Salmonella inoculated surfaces, IPAQuats was the most effective achieving over 4.5 log CFU/coupon reduction on both canvas and cordura surfaces. Our studies demonstrated that bacteria could survive for over 21 d under different conditions and could transfer from contaminated harvest bag surfaces to apples underlining the importance of cleaning and sanitizing harvest bags with sanitizers like IPAQuats.
- An Examination of Food Handling Practices at Food PantriesGuinee, Aislinn (Virginia Tech, 2023-06-05)The latest edition of the Food and Drug Administration's Model Food Code provides the definition of an acceptable donated food item but does not specify any safe storage or handling standards for these items. Virginia has not adopted this edition, but its own food handling regulations provide liability protections to food donors and exempt food pantries from any relevant retail food handling regulations. This means that food pantries must provide their own oversight over implementation of safe food handling requirements. Some pantries only accept nonperishables, but others accept both perishable and nonperishable food, or prepare/repurpose food on site. Therefore, pantries have varying needs in terms of safe food handling and preparation oversight and guidance. This project aims to observe food safety practices at food pantries within Virginia, and to establish a set of recommendations based on these observations for food pantries to consider implementing. Twenty pantries throughout the Commonwealth of Virginia were observed when distributing food using a standardized rubric. This rubric allowed the observer to collect detail on food storage, handling, and preparation at the pantry. Each pantry was visited once and observed for about two hours. The manager of the pantry completed a survey to determine basic food safety knowledge. Generally, pantries successfully followed basic food safety guidelines, however there were some clear risky practices observed. These included improper handwashing, improper storage of perishable items, and improper volunteer personal hygiene. There were only two handwashing attempts observed between all 20 pantries and neither of these attempts was correct. In addition, 8 of 20 (40%) of the pantries did not keep up to date records of their refrigerator and freezer temperatures. Lack of personal hygiene, especially the use of personal items while handling food and lack of glove usage, was a concern. 9 of 20 (45%) of pantries had someone on site using a personal item while handling food, and 4 of 6 (67%) of pantries that prepared or cooked food on site had volunteers improperly wearing gloves during these activities. Managers at seventeen of twenty (85%) pantries reported completing some type of food safety training while only volunteers at six of twenty (30%) pantries reported the same. This demonstrates gaps in knowledge between volunteers and managers. The results of this study demonstrate the need for standard operating procedures (SOPs) to be made available for food pantries, as well as a food safety training created specifically for food pantry volunteers that is applicable to their scope of work.
- Factors Associated with Foodborne Pathogens and Fecal Indicator Organisms in Virginia Agricultural SoilsCook, Camryn Grace (Virginia Tech, 2023-06-05)Prior research reveals foodborne pathogens, as well as enteric bacteria, can thrive in agricultural soils. Understanding how macro- and micronutrients, as well as meteorological factors and observational factors, impact pathogen prevalence may promote a better understanding of how pathogens persist in agricultural soils. This study aimed to (i), characterize associations between soil properties (e.g., macro- and micro-nutrient levels) and microbial targets (e.g., S. enterica and L. monocytogenes prevalence, fecal indicator bacteria concentration). Three produce farms in Virginia were selected from different regions (i.e., Blue Ridge Highlands, Piedmont, Coastal Plains). Farms were sampled four times to capture seasonal differences. Five soil samples were collected from 20 plots (25m2) and pooled in equal quantities to form one sample per plot. A total of 240 samples were collected. Listeria and S. enterica samples (25g) were processed using a modified FDA BAM method, while generic Escherichia coli (gEC) and total coliform (TC) samples (5g) were enumerated using Petrifilm. Presumptive Listeria and S. enterica positive samples were confirmed by PCR using a single gene. Bayesian mixed models were used to evaluate associations with each foodborne pathogen and indicator organism with factors of interest. S. enterica prevalence was 4.2% (10/240) in soil samples. Of the ten S. enterica positive samples, nine samples (90%) were from one farm in eastern VA. Listeria spp. prevalence was 10% (24/240) with L.monocytogenes prevalence being 2.5% (6/240). The average gEC and TC concentrations in soil samples were 1.53 (range 0.95-4.01) and 4.21 (range 1.23-7.12) log CFU/g, respectively. Bayesian mixed models revealed that pH impacted prevalence of L. monocytogenes and gEC (MAP=5.48, 95% CI=0.75,345.39, PD=0.98, ROPE=0.01), and (MAP=4.87, 95% CI=2.31,12.22, PD=1.00, ROPE=0.00). There was no evidence of an association between S. enterica prevalence and factors of interest. S. enterica was 11.55 times more likely to be detected on Farm C (where prevalence was highest) compared to other farms (95 % CI= 1.36, 1155.27, PD=0.98, ROPE=0.00). Findings show that while soil nutrient trends differ across all farms, it is difficult to determine the strength of these trends due to strong regional distinctions.
- Factors Influencing The Ecology and Epidemiology of Microbial Indicators and Foodborne Pathogens In Surface Waters and Development of Risk MitigationsMurphy, Claire Margaret (Virginia Tech, 2023-04-25)Foodborne outbreaks have continued to be associated with produce contamination originating from on-farm sources, such as soil or agricultural water. Additionally, the heterogeneity of the pre-harvest environment complicates the development of universal strategies for managing produce safety risks. Understanding the ecology and epidemiology of foodborne pathogens and fecal indicator bacteria (FIB) by growing regions, sample types, scale of analysis, and detection method is essential for developing targeted mitigation strategies. This dissertation utilized quantitative research methods and statistical modeling to examine the impact of sampling method, spatial, temporal, meteorological, and physicochemical factors on pathogen prevalence and FIB levels. Key findings highlight that the drivers of prevalence differ between pathogens and were influenced by sample type, scale, and region.. The variations in associations emphasize that risk varies by space and time. Therefore, results support regional and scale-dependent food safety standards and guidance documents for controlling hazards to minimize risk. Additionally, the method used for pathogen detection influences prevalence highlighting the need for standard methods since methodological differences confound comparisons across studies. Furthermore, since agricultural water quality is an important food safety priority, this dissertation aimed to determine the efficacy of chemical antimicrobial sanitizers against Salmonella in pre-harvest agricultural water. Results demonstrated that certain sanitizer treatments and conditions can significantly reduce Salmonella populations in preharvest agricultural water sources and thus may serve as a risk reduction option when used correctly.
- Using Flavor Chemistry, Sensory, and Texture to Determine Domestic Edamame QualityMiller, Rebekah Jane (Virginia Tech, 2024-05-23)Persistent interest in edamame, vegetable soybean (Glycine max (L.) Merr.), by U.S. consumers has continued to fuel the development of a domestic edamame supply chain. Studies have shown edamame to be a nutritious specialty crop with potential to provide economic benefit to local growers. Domestically bred and grown edamame has shown to be preferred by growers and consumers with competitive agronomic traits. While domestic varieties of edamame will encourage growers to produce a product catered towards the domestic market, additional considerations of final product quality are necessary to positively influence the market success. Domestically grown and store-bought edamame samples were utilized to research quality attributes including flavor, taste, and texture of edamame representative of domestic market and supply chain. Solid phase microextraction was utilized for aroma extraction prior to gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O) analyses to obtain (1) impactful volatile compounds present, (2) changes in these compounds by stink bug feeding injury, and (3) volatile contributions to sensory characteristics. Sensory methods were utilized to (1) evaluate differences in perception of edamame with and without stink bug feeding injury, and (2) understand important sensory characteristics for domestic edamame. Volatile analysis recognized 16 volatile compounds when investigating edamame genotypes with 14 compounds having significant differences in contents by genotype. Only 10 compounds were consistently detected through GC-O by panelists, so called aroma-active compounds, and only one compound (E)-2-octenal was significantly different in odor intensities across genotypes. Stink bug injured samples showed dramatic differences in volatile profile compared with the not injured counterpart, from mass chromatogram; however, no noticeable differences were perceived by GC-O or sensory difference testing. An instrumental texture analysis method was proven to be sensitive enough to detect the textural differences of edamame beans after processing. The multi-dimensional sensory characteristics including taste, aroma, and texture, were established showing significant differences by edamame variety and growing location. Domestically bred edamame was found to be sweeter, as is preferred by domestic consumers, confirming encouraging breeding outcome. Despite significant differences in edamame volatile profiles by genotype and stink bug feeding injury, sensory discrimination of these differences seems to be less noticeable than changes from taste and texture. Utilizing our findings toward future research and product development will support the domestic edamame supply chain by providing a foundational understanding of quality attributes and their impacts.