Browsing by Author "Williams, Robert C."

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    Airborne Campylobacter in a Poultry Processing Plant
    Johnson, Anjeanette Christina (Virginia Tech, 2010-05-29)
    Campylobacter is a foodborne pathogen commonly found in live poultry and raw poultry products. Identifying areas of contamination or modes of transmission during commercial processing can lead to strategies to reduce the level of Campylobacter on finished products. Monitoring levels of airborne Campylobacter may be useful for identifying the presence or relative concentration of the pathogen in a processing plant environment. In this study, air sampling was used to detect and quantify Campylobacter in a commercial chicken processing plant by location within the plant and collection time during the day. Air was sampled from evisceration and post-chill areas in a poultry processing plant on four days and at 4 hour intervals onto Campy-Cefex agar plates or gelatin filters that were subsequently transferred to Campy-Cefex agar plates. Additionally, pre-evisceration and post-chill carcass rinses were analyzed quantitatively for Campylobacter. The mean level of airborne Campylobacter was 5 CFU/1000L of air sampled (10% samples positive) in comparison with 413 CFU/mL from carcass rinses (70% samples positive). Higher concentrations were found in carcass rinse samples from pre-evisceration. Airborne Campylobacter was detected from the evisceration area more frequently than from the post-chill carcass area of the plant (P < 0.05). This study shows that airborne Campylobacter can be quantified with a selective agar and with gelatin filter collection. Further research is needed to prove the utility of airborne detection of Campylobacter for estimating the relative contamination level of live poultry flocks and the processing plant environment and the potential for cross-contamination.
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    Assessment Of Consumer Perceptions About Food Processing Technologies For Cooperative Extension Educational Initiatives
    Arnold, Nicole Leanne (Virginia Tech, 2019-09-25)
    New food processing technologies are needed to create safe, high-quality food products that are still considered "fresh" by consumers. Despite the numerous benefits attributed to 'food processing', consumers continue to perceive the term negatively. Consumer acceptance of foods processed with different technologies generally increases when factual information is provided to the consumer. Educators working within Cooperative Extension are a resource for public dissemination of food information. By working directly in the community, Extension educators often cultivate positive relationships with local clientele. Therefore, Extension educators can dispel myths related to food processing technologies and deliver science-supported information to the general public. Consumer knowledge, perceptions, and purchasing intentions associated with both conventional and emerging food processing technologies were assessed through a nationwide telephone survey administered by Virginia Tech's Center for Survey Research Center. A similar version of the telephone survey was disseminated in an online format to Virginia Extension agents. An additional section of the online survey served as a needs assessment for educational materials related to food processing technologies. A grounded theory methodology was used for qualitative coding in both surveys. Approximately 67% of consumers expressed concerns towards the term "processed foods." The majority of Extension agents (67.4%) expressed concerns about foods that had been processed, citing additional ingredients, preservatives, and additives; safety; and health implications. Both the consumer and Extension agent groups were more likely to be supportive of light-exposed foods to enhance food safety and quality, in comparison to gas-exposed foods. Although agents may be familiar with some food processing technologies, they may not have the resources to understand the scientific mechanisms for which a technology is able to increase food safety. Consumer education regarding emerging technologies is necessary to anticipate potential consumer concerns; however, agents still lack resources and information about existing and frequently used food processing technologies. Educational interventions are needed to provide information to consumers and increase their acceptance of new and currently used processing technologies so that the food industry can effectively target emerging issues related to food.
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    Assessment of consumers' knowledge, attitudes, awareness, and beliefs of food handling and beef safety handling behaviors
    Yang, Lily L. (Virginia Tech, 2018-08-03)
    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.
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    Assessment of Farmers Market Practices and Characteristics to Inform the Development of Tailored Educational Materials
    Duong, 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.
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    Association of foodborne pathogens with Capsicum annuum fruit and evaluation of the fruit for antimicrobial compounds
    Huff, Karleigh Rose (Virginia Tech, 2011-09-07)
    Hot peppers are gaining popularity in the United States as both a vegetable and a spice. In 2008, jalapeño peppers were involved in a multistate outbreak of Salmonella Saintpaul. This is the first outbreak implicating jalapeño as a vehicle for foodborne illness. Hot peppers contain many compounds thought to possess antimicrobial characteristics. This research was conducted to provide more information on the interactions of pathogenic bacteria and jalapeño peppers, as well as to identify properties of Capsicum annuum that affect bacterial survival, growth, and inhibition. Behavior of pathogens associated with jalapeños was investigated by inoculating jalapeño fruits with a cocktail of Listeria monocytogenes, Salmonella enterica, or Escherichia coli O157:H7 on the intact external surface, injured external surface, or intact internal cavity and storing the jalapeños at 7°C or 12°C. Intact external jalapeñosurfaces did not support the growth of the bacteria tested under storage conditions of 7°C. However, L. monocytogenes populations remained detectable throughout the 2 week study. At 7°C, pathogenic bacteria were able to survive but not grow on injured and internally inoculated jalapeño, but populations increased at 12°C (p=0.05). The most supportive growth environment for the pathogenic bacteria was the internal cavity of jalapeño held at 12°C. This study demonstrated the importance of intact uninjured produce and proper storage temperatures for food microbial safety. Inhibitory properties of jalapeños were studied by making extracts from fresh jalapeño peppers to test for antimicrobial activity. A disk diffusion assay determined that the extracts were capable of inhibiting the growth of the pathogenic bacteria tested. Listeria monocytogenes was especially sensitive to the extracts. jalapeño extracts were fractionated using HPLC and used for inhibition assays using disk diffusion and growth curve generation. Two fractions stimulated bacterial growth (p=0.05), while two other fractions inhibited bacterial growth. The inhibitory fractions were separated further using HPLC and tested for antimicrobial activity. Fraction E1 suppressed the growth of L. monocytogenes. HPLC-MS analysis revealed that Fraction E1 contained compounds known as capsianosides. To prove that inhibition is caused by capsianoside(s) and determine minimum inhibitory concentrations, a method to isolate the pure compound should be developed.
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    Association of Salmonella enterica serotype Newport with Tomato Plants through Irrigation Water, Grown under Controlled Environmental Conditions
    Hintz, Leslie Diane (Virginia Tech, 2008-11-21)
    Tomato fruit have been associated with numerous outbreaks of salmonellosis in recent years. Trace back suggests tomato fruit may become contaminated during pre-harvest, however exact routes are unclear. The objective of this study was to determine the potential for Salmonella enterica serotype Newport to be associated with the roots, leaves, stems, and ultimately fruit of red round tomato plants through contaminated irrigation water, at various stages of plant development, when grown under controlled environmental conditions. Tomato plants were individually root irrigated with 250 or 350 ml (depending on growth stage) of 7 log CFU/ml S. Newport contaminated irrigation water every seven days. Presence of the pathogen in plant tissue was evaluated at five growth stages; 14 days post transplant, early fruit, mid fruit, full fruit, and terminal stages. At each stage, roots, stems, leaves, and two tomato fruit, if present, from four S. Newport and four water irrigated (negative control) tomato plants were sampled for S. Newport contamination. Association of S. Newport was detected in tomato roots and stems using both conventional plating and molecular techniques. Twenty-four samples were confirmed positive for S. enterica using PCR. Sixty-five percent of the roots, 40% of the stems, 5% of the leaves and 5% of the fruit sampled were confirmed to contain S. enterica. Overall, there was significant difference in the presence of S. Newport according to tissue sampled (roots > stems > leaves and fruit) (P > 0.05). There was no correlation between growth stage and presence of S. Newport in tissues (P > 0.05). Ultimately, irrigation with S. Newport has a low probability of contaminating tomato fruit.
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    Beef Quality Assurance - Adding Value with E. coli Food Safety Focus
    Flowers, Charles Webb (Virginia Tech, 2011-12)
    “Doing the right thing” as recommended by cumulative results of successive National Beef Quality Audits 1990–2010 is demonstrating positive end product quality, wholesomeness and food safety progress. As producers continued to utilize BQA practices over a 10-20 year period during the 1990s and 2000s, and included additional value added practices, they began to realize premiums for BQA practices. The focus of this publication is the importance of minimizing opportunities for foodborne illness pathogen to occur throughout the life of beef cattle for young calves through harvest.
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    Bridging the CGMP Gap Between the U.S. Government, Academia, and the Food Industry
    West, Joey (Virginia Tech, 2012-12)
    In communication theory, one of the most important aspects is to always remember who the audience is at all times. In this case, the audience are members of the food industry who are expected to translate the knowledge of the CGMPs into practice. The goal of this research is twofold; to effectively communicate the need and nature of the CGMPs and to simply reconnect the regulations to the audience they were developed to assist. Further, a definition of perception is an individual’s capacity for comprehension. We find that in the real world, an individual’s comprehension does not always neatly fit inside the perimeters that the CGMPs provide. In some cases compliance with regulations does not allow for continuation of traditional processing methods, short-cuts, and individual bias when it comes to how firms may prepare, process, hold, and ship food products. That leaves it up to the government to find a means to bridge the gaps that exist between comprehension, perception, and reality. The main focus is to present information so that the ordinary person can understand and act upon the regulation on a consistent basis. The answer may lay not in the regulation itself, but Food Industry members’ ability to relate to and understand the need for compliance.
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    Cetylpyridinium chloride direct spray treatments reduce Salmonella on cantaloupe rough surfaces
    Saucedo-Alderete, Raúl O.; Eifert, Joseph D.; Boyer, Renee R.; Williams, Robert C.; Welbaum, Gregory E. (2018-08)
    Cetylpyridinium chloride (CPC) solutions (0, 0.5, or 1.0%) were applied to cantaloupe (Athena and Hale's Best Jumbo cultivars) rind plugs, either before or after inoculation with a broth culture of Salmonella Michigan (10(9) CFU/mL) and held at 37 degrees C for 1 or 24 hr. Rind plugs were diluted, shaken, and sonicated, and solutions were enumerated. Texture quality and color were evaluated over 14 days storage at 4 degrees C after 0 and 1% CPC spray applications. A 0.5 or 1.0% (vol/vol) application of CPC after Salmonella reduced the pathogen levels between 2.34 log CFU/mL and 5.16 log CFU/mL in comparison to the control (p<.01). No differences were observed in the firmness and color of 1% CPC treated cantaloupes. Salmonella concentrations on cantaloupes, treated with 1.0% CPC, were lower after 1 hr storage as compared to 24 hr. And, Salmonella on Athena surfaces were more susceptible to CPC spray treatments than on Hale's Best Jumbo. Practical applicationsCetylpyridinium chloride (CPC) is the active ingredient of some antiseptic oral mouth rinses, and has a broad antimicrobial spectrum with a rapid bactericidal effect on gram-positive pathogens. The spray application of CPC solutions to cantaloupe may reduce the level of Salmonella surface contamination during production from irrigation water and manure fertilizers and, during food processing by contaminated equipment and food handlers. Since the surfaces of cantaloupes are highly rough or irregular, bacteria can easily attach to these surfaces and become difficult to remove. Appropriate postharvest washing and sanitizing procedures are needed that can help control Salmonella and other pathogens on melons, especially on cantaloupes with nested surfaces. A direct surface spray application of CPC may be an alternative antimicrobial postharvest treatment to reduce pathogen contamination of cantaloupe melons, while providing an alternative to chlorine-based solutions.
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    Characterization of alpha-cyclodextrin inclusion complexes with trans-cinnamic acid in an acid-based beverage system
    Romano, Dina Lynn (Virginia Tech, 2008-04-11)
    In response to a need for a natural antimicrobial to replace sodium benzoate, cinnamic acid was chosen. Due to cinnamic acid's solubility issues, α-cyclodextrin was used as a host molecule to form an inclusion complex with the cinnamic acid molecule. The cinnamic acid: α-cyclodextrin inclusion complex was then characterized using phase solubility analysis, proton nuclear magnetic resonance (H-NMR), and solid inclusion. Phase solubility analysis verified the maximum amount of cinnamic acid that α-cyclodextrin was able to host. H-NMR was used to determine the complex association constant, determine the chemical shifts of available protons, and yield a stoichiometry for the complex. The solid inclusion complex allowed for a physical formation of the complex, yielding further information in support of the complex stoichiometry. Microbiological tests were also performed to quantify the antimicrobial abilities of the complex, the guest, and the host against the yeast Saccharomyces cerevisiae and mold Paecilomyces variotii. Results indicated that approximately 990.29 ppm in aqueous solution was the maximum amount of cinnamic acid in the complex. The 2:1 stoichiometry yields an association constant of 21.7 M-1. Results also indicated that the cinnamic acid readily conformed to fit within the α-cyclodextrin host molecule, which remained a rigid structure. An 8.9% weight to weight of cinnamic acid was calculated for the solid inclusion again reinforcing a 2:1 stoichiometry. Microbiological studies showed little to no inhibition power by the complex at varying concentrations against S. cerevisiae and P. variotii. Free cinnamic acid showed greater antimicrobial activity compared with free α-cyclodextrin and the complex.
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    Consumer Knowledge of Fresh Produce Safety and the Food Safety Modernization Act
    Schrier, Stevie (Virginia Tech, 2014-05)
    Between 1976 and 2012, there has been an increase in fresh fruit consumption from around 31 kg. (68 lbs.) of fruit per capita to around 136 kg. (300 lbs.) per capita and consumption of fresh vegetables has increased from around 45 kg. (100 lbs.) per capita to around 181 kg. (400 lbs.) per capita (Tables 2 and 3) (Cook, 2013). Most of the fresh produce is consumed raw. In the United States there are approximately 48 million cases of food borne illnesses reported every year resulting in 3,000 deaths (USDA- FSIS, 2013), and according to the Centers for Disease Control and Prevention (CDC) between the years of 1998 and 2008 almost half of the food borne illnesses were from consuming fresh produce (CDC, 2014a). This paper reviews current programs to prevent food borne illnesses in produce, including Good Agricultural Practices and the Food Safety Modernization Act. A consumer survey was also delivered to adults in Louisa County, Iowa, to determine the extent of their awareness of safe produce handling, common pathogens found on produce, and legislation affecting the safety of produce.
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    Control of Listeria monocytogenes in Cheese Brines: A Literature Review
    Hoffman, Mary (Virginia Tech, 2018-05-03)
    Listeria monocytogenes (L. mono.) is a top pathogen of concern in the cheese industry. The organism is prevalent in the environment and has been known to inhabit dairy manufacturing facilities, including long-term survival in brine tanks. Along with good hygiene and sanitation practices, validated L. mono. control methods must be employed to ensure extended-use brine tanks do not become reservoirs for Listeria monocytogenes, potentially leading to serious health issues in cheese consumers. Control methods considerations include L. mono. cells in suspension, cells attached to protective biofilms, and effectiveness in the presence of organic matter. This literature review investigated the availability of scientific research on effective control methods for Listeria monocytogenes in cheese brines. Research on L. mono. control in other applicable areas was considered where information related specifically to cheese brine environments was not found. Potential effective control methods were identified, including membrane filtration and oxidizing agents such as peroxyacetic acid and hydrogen peroxide. Further research is needed to fill knowledge gaps related to successful implementation of these controls in cheese brines.
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    Cyberbiosecurity: A New Perspective on Protecting US Food and Agricultural System
    Duncan, Susan E.; Reinhard, Robert; Williams, Robert C.; Ramsey, A. Ford; Thomason, Wade E.; Lee, Kiho; Dudek, Nancy; Mostaghimi, Saied; Colbert, Edward; Murch, Randall Steven (Frontiers, 2019-03-29)
    Our national data and infrastructure security issues affecting the "bioeconomy" are evolving rapidly. Simultaneously, the conversation about cyber security of the U.S. food and agricultural system (cyber biosecurity) is incomplete and disjointed. The food and agricultural production sectors influence over 20% of the nation's economy ($ 6.7T) and 15% of U.S. employment (43.3M jobs). The food and agricultural sectors are immensely diverse and they require advanced technologies and efficiencies that rely on computer technologies, big data, cloud-based data storage, and internet accessibility. There is a critical need to safeguard the cyber biosecurity of our bio economy, but currently protections are minimal and do not broadly exist across the food and agricultural system. Using the food safetymanagement Hazard Analysis Critical Control Point systemconcept as an introductory point of reference, we identify important features in broad food and agricultural production and food systems: dairy, food animals, row crops, fruits and vegetables, and environmental resources (water). This analysis explores the relevant concepts of cyber biosecurity from food production to the end product user (such as the consumer) and considers the integration of diverse transportation, supplier, and retailer networks. We describe common challenges and unique barriers across these systems and recommend solutions to advance the role of cyber biosecurity in the food and agricultural sectors.
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    Delmopinol hydrochloride reduces Salmonella on cantaloupe surfaces
    Saucedo-Alderete, Raúl O.; Eifert, Joseph D.; Boyer, Renee R.; Williams, Robert C.; Welbaum, Gregory E. (Wiley, 2017-11-15)
    Since the surfaces of cantaloupes are highly rough or irregular, bacteria can easily attach and become difficult to remove. Appropriate postharvest washing and sanitizing procedures can help control Salmonella and other pathogens on cantaloupe or other melons during postharvest operations. Delmopinol hydrochloride (delmopinol) is a cationic surfactant that is effective for treating and preventing gingivitis and periodontitis. The application of delmopinol to two cantaloupe cultivars was evaluated for reducing the level of inoculated Salmonella. Athena and Hale’s Best Jumbo (HBJ) cantaloupe rind plugs (2.5 cm. dia.) were inoculated with nalidixic acid-resistant Salmonella Michigan (approx. 1.0 × 109 CFU/ml). After 15 min, rind plugs were sprayed with 10 ml of a delmopinol spray solution (0% or 1.0% vol/vol) and held at 35°C for 1 hr or 24 hr. Rind plugs were diluted with Butterfield’s phosphate buffer, shaken and sonicated, and solutions were enumerated on 50 ppm nalidixic acid-tryptic soy agar. The texture quality and color of additional cantaloupes were evaluated, after 1% delmopinol spray treatment, over 14-day storage at 4°C. A 1.0% application of delmopinol after 1 hr reduced Salmonella concentration by ~3.1 log CFU/ml for both “HBJ” skin rind plugs and “Athena” stem scar rind plugs in comparison to the control (p < .05). No differences were observed in the texture and color (L*, a*, b* values) of 1% delmopinol-treated cantaloupes as compared to control. Storage of cantaloupes treated with 1.0% delmopinol solution for 1 hr had a greater effect on reducing concentration of Salmonella compared to 24-hr treatment. A surface spray application of 1% delmopinol on cantaloupes could be an alternative antimicrobial postharvest treatment that could make surface bacteria more susceptible to sanitizers or physical removal.
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    Developing Hygienic Practices Training for Meat Processing Industry
    Cappaletti, Chiara (Virginia Tech, 2011-04-15)
    This final project focuses on safe handling and risk management in meat production. Deliverables include Hygienic Practices Manual, Hazard Analysis & Critical Control Point Procedures, and Employee Training Plan for Fiorucci Foods, Inc.
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    Developing resources to help Virginia food producers sell and distribute products through the farm to school program
    Haynes, Brenda Carol (Virginia Tech, 2019-05-15)
    Encouraging procurement of food via Farm to School programs has become an emphasis of many schools throughout our nation and state. Farm to school produce/products benefits children and communities in many different ways. Contact between farmers and school management needs to be fostered and nurtured to be successful and provide the students with the freshest and safest product possible. School divisions often need a starting point to begin the process of procurement between the local farmer and the school nutrition department. Development of a checklist and other tools for farmers and school division nutrition managers/cafeteria managers to use when gaining access to fresh local produce may be beneficial for school nutrition departments trying to start a farm to school program. This project developed a checklist and fact sheets to lead and guide school nutrition directors and producers seeking to increase purchases and consumption throughout the state of Virginia. Farm to school is a vital program and allows farmers to reach markets that may have been untouched in the past. We are excited to share our resources and information with educators, farmers, and nutrition directors as well as our colleagues in extension.  
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    Development of an On-line Food Safety Training Course for Food Distributors.
    Barker-Smith, Anne (Virginia Tech, 2010-05)
    Food Distribution is integral to the food supply system in the United States. Our food comes from many sources and must be shipped to many more before the consumer is able to take control. Product handling and storage conditions during this phase are critical to the overall quality and safety of the food. Having worked for a major foodservice distribution organization in the area of quality assurance, for 25 years, it became apparent that food quality and food safety was becoming more and more important to the consumer. Distributors needed to provide documentation as evidence of proper food safety practices because not only was it becoming critical to regulators but to customers as well. Working with Virginia Tech’s food science department and others, I developed and delivered distributor appropriate training for over 250 managers. The positive result was that customer complaints caused by product mishandling were significantly reduced. Unfortunately over that same period, it became apparent that these managers needed assistance in training their teams after they went home and began building their programs. The request for a simplified, job appropriate training program for staff became a consistent theme.
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    The Development of Mathematical Models for Preliminary Prediction of Highway Construction Duration
    Williams, Robert C. (Virginia Tech, 2008-11-04)
    Knowledge of construction duration is pertinent to a number of project planning functions prior to detailed design development. Funding, financing, and resource allocation decisions take place early in project design development and are significantly influenced by the construction duration. Currently, there is not an understanding of the project factors having a statistically significant relationship with highway construction duration. Other industry sectors have successfully used statistical regression analysis to identify and model the project parameters related to construction duration. While the need is seen for such work in highway construction, there are very few studies which attempt to identify duration-influential parameters and their relationship with the highway construction duration. This research identifies the project factors, known early in design development, which influence highway construction duration. The factors identified are specific to their respective project types and are those factors which demonstrate a statistically-significant relationship with construction duration. This work also quantifies the relationship between the duration-influential factors and highway construction duration. The quantity, magnitude, and sign of the factor coefficient yields evidence regarding the importance of the project factor to highway construction duration. Finally, the research incorporates the duration-influential project factors and their relationship with highway construction duration into mathematical models which assist in the prediction of construction duration. Full and condensed models are presented for Full-Depth Section and Highway Improvement project types. This research uses statistical regression analysis to identify, quantify, and model these early-known, duration-influential project factors. The results of this research contribute to the body of knowledge of the sponsoring organization (Virginia Department of Transportation), the highway construction industry, and the general construction industry at large.
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    Effect of a Fermented Yeast Product on the Gastrointestinal Tract Microbial Diversity of Weaned Pigs Challenged With Salmonella Enterica Typhimurium Dt104
    Totty, Heather Renae (Virginia Tech, 2009-11-13)
    Gastrointestinal tract (GIT) microorganisms play important roles in animal health, including providing energy and vitamins, improving the host immune response and preventing pathogenic microorganisms from colonizing. Prebiotic feed supplementation offers an alternative to antimicrobial growth promoters by stimulating key populations of the GIT bacteria that can ferment these non-digestible compounds, producing various short chain fatty acids used by the animal. The objective of this study was to quantify the effects of a proprietary Saccharomyces cerevisiae fermentation product (XPC, Diamond V Mills, Inc., Cedar Rapids, IA) inclusion in nursery diets on the microbial diversity and growth performance of pigs before, during and after an oral challenge with Salmonella. Pigs (n= 40) were weaned at 21 d of age, blocked by body weight (BW) and assigned in a 2Ã 2 factorial arrangement consisting of diet (control or 0.2% XPC) and inoculation (broth or Salmonella). Diet had no effect on pig growth performance prior to inoculation; however, consumption of XPC altered the composition of the gastrointestinal microbial community resulting in increased growth performance prior to inoculation. After Salmonella infection, XPC altered the composition of the gastrointestinal microbial community resulting in increased (P < 0.05) populations of Bacteroidetes and Lactobacillus. Infection with Salmonella and treatment of the piglets with ceftiofur-HCl resulted in alterations to the species richness and abundance of key members of the GIT community. The addition of XPC to the diets of weaning pigs results in greater compensatory gains after infection with Salmonella and an increase in beneficial bacteria within the GIT.
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    Effect of Alternative Household Sanitizing Formulations Including: Tea Tree Oil, Borax, and Vinegar, to Inactivate Foodborne Pathogens on Food Contact Surfaces
    Zekert, Ashley Elizabeth (Virginia Tech, 2009-11-09)
    Current trends indicate that American consumers are increasingly selecting products that they believe to be environmentally friendly or "natural." In the kitchen, this trend has been expressed through greater desire for using alternative or "green" sanitizers instead of bleach or other common chemical sanitizers. The purpose of this work was to evaluate the effectiveness of one suggested alternative, tea tree oil, as a food contact surface sanitizer. Three foodborne bacterial pathogens (Listeria monocytogenes N3-031 serotype 1/2a, Escherichia coli O157:H7 strain E009, and Salmonella Typhimurium ATCC 14028) were applied separately onto three different food contact surfaces (high density polyethylene, glass, and Formica® laminate). Tea tree oil (TTO), borax, and vinegar (5% acetic acid) were applied individually as well as in combination for a total of seven treatment solutions. In addition, household bleach (6.15% sodium hypochlorite), sterile reverse osmosis (RO) water, and no applied treatment were used as controls. Treatments were tested using an adaptation of the Environmental Protection Agency DIS/TSS-10 test method, whereby each contaminated surface was treated with 100 µl of test solution and held for 1 min followed by submersion in neutralizing buffer and microbiological plating. Samples (0.1 ml) were plated onto TSA and incubated at 35°C for 48 h prior to colony counting. Bleach reduced microbial populations significantly with greater than 5-log reduction reported for all surfaces (Formica® laminate, glass, and HDPE), against E. coli O157:H7, L. monocytogenes, and S. Typhimurium. TTO produced reductions between four and five logs for E. coli O157:H7, L. monocytogenes, and S. Typhimurium and was not statistically different from the vinegar treatment (P>0.05). All combination recipes, including the borax treatment, failed to produce reductions in microbial populations at levels considered to be appropriate for food contact surface sanitizers. Surface type did not play a significant role in the effectiveness of the treatment (P>0.05). Although TTO and vinegar did reduce pathogen populations on surfaces, reductions were not sufficient enough to be considered an equally effective alternative to household bleach.