Master of Science / Department: Diagnostic Medicine/Pathobiology / Douglas Powell / Folklorama in Winnipeg, Manitoba, Canada is a 14-day temporary food service event that explores the many different cultural realms of food, food preparation, and entertainment. The ethnic nature and diversity of foods prepared within each pavilion presents a unique problem for food inspectors as each culture prepares food in their own very unique way. In 2010, the Russian pavilion at Folklorama was implicated in a foodborne outbreak of E.coli O157 causing 37 illnesses and 18 hospitalizations. Both the Department of Health and Folklorama Board of Directors realized a need for implementation of a food safety delivery program that would be more effective than a simple 2-hour food safety course delivered via PowerPoint slides. Until 2011, the 2-hour food safety course delivered to event co-ordinators and food operators for Folklorama pavilions was not mandatory. The course is now mandatory in 2011 for all Folklorama pavilions. Five randomly chosen pavilions were trained on-site, in their work environment, focusing on critical control points specific to their menu. A control group (five pavilions) did not receive on-site food safety training. Critical infractions noted on standardized food inspection reports were assessed. Results of the current study suggest no statistically significant difference in food inspection scores between the trained group and control group. Results imply that the 2-hour food safety course delivered via slides was sufficient to pass public health inspections.

Master of Science / Department of Human Nutrition / Koushik Adhikari / Three cuts of steak (strip, chuck-eye and top blade) of two United States Department of Agriculture grades (choice and select) underwent seasoning and tenderization treatments to study whether flavor and texture quality could be enhanced within cut and grade of steak. Treatments included: 1) seasoning alone, 2) a combination of seasoning + bromelain (enzymatic tenderizer), or 3) control (no seasoning and/or bromelain). The seasoning included: kosher salt, black pepper, onion powder, garlic powder, cumin, and ground oregano. All of the steaks were cooked to an internal temperature of 71° C (medium doneness). Six trained descriptive panelists evaluated the samples. The results of this study indicate that it may be possible to improve eating quality of choice and select chuck-eye and choice top blade to be more similar to strip steaks of the same USDA grade. Both treatments increased flavor and texture attributes in these samples that have been shown to have an impact on liking scores. Choice chuck-eye samples had decreased bloody/serumy and metallic scores and increased umami and initial flavor impact with both treatments. Both treatments increased brown/roasted flavor in select chuck-eyes. Tenderness, fat-like and umami were increased with the seasoning + bromelain treatment in select chuck-eyes. Choice top blade steaks with seasoning alone had increased umami flavor. Both treatments impacted attributes (fat-like, umami and sour) of the select strip steak that differed from choice strip steaks. The next step to this research is to investigate whether consumer liking scores are consistent with conclusions made from descriptive analysis results. Overall, these treatments could be a valuable tool for beef retailers.

Doctor of Philosophy / Food Science / Daniel Y.C. Fung / James L. Marsden / The ubiquitous nature and continued presence in food processing environments makes Listeria monocytogenes a significant threat in ready-to-eat (RTE) food products. This study was performed in two phases; Phase 1 studied lauric arginate (LAE) as an antimicrobial on food contact surfaces and shredded mozzarella cheese, and use of glucose oxidase (GOX), sodium lactate (SL), and acidified calcium sulfate (ACS) as preservatives in mozzarella cheese; Phase 2 evaluated efficacy of Photohydroionization (PHI) technology to control L. monocytogenes on food contact surfaces, sliced American cheese, and ready-to-eat turkey. Stainless steel coupons, mozzarella cheese, American cheese, and turkey were surface inoculated with a three- or five-strain cocktail of L. monocytogenes. Coupons were treated with 100 and 200 ppm solution of lauric arginate for 5 and 15 min. Mozzarella cheese was treated with different combinations of treatments comprising LAE, GOX, SL, ACS, dextrose, and anticaking agents (free flow 1031 and cellulose). Results indicated up to 2.5 log CFU/coupon reductions and it was concluded that LAE was effective in controlling low levels of contamination of L. monocytogenes on food contact surfaces. In mozzarella cheese, results indicated that lauric arginate provided no additional antimicrobial effect (P > 0.05) as compared to GOX + dextrose. The antimicrobial blends with GOX, SL, and ACS were different (P < 0.05) from the controls but showed no differences (P > 0.05) in their effect in controlling bacterial populations. Results from treatment with PHI unit showed significant (P < 0.05) reduction in bacterial populations. L. monocytogenes populations reduced by 4.37 log CFU/coupon on stainless steel surfaces after 15 min of treatment; 2.16 and 2.52 log CFU/sample reduction on American cheese and ready-to-eat turkey, respectively, after short treatment time of 5 min. Lipid oxidation analyses performed on cheese and turkey samples indicated that the PHI treatment did not affect (P > 0.05) TBAR values. These studies suggest that LAE and GOX as antimicrobials and PHI treatment can be used as intervention strategies in an integrated process to ensure safe production of food. Further research is needed to evaluate applicability of SL and ACS in mozzarella cheese.

Master of Science / Food Science / Kelly J. K. Getty / Dry-processing environments are particularly challenging to clean and sanitize because water introduced into systems not designed for wet cleaning can favor growth and establishment of pathogenic microorganisms such as Salmonella. The objective was to determine the efficacy of isopropyl alcohol quaternary ammonium (IPAQuat) formula and carbon dioxide (CO[subscript]2) sanitizer system for eliminating Enterococcus faecium and Salmonella on food contact surfaces. Coupons of stainless steel and conveyor belting material used in dry-processing environments were spot-inoculated in the center of 5 × 5 cm coupons with approximately 7.0 log CFU/ml of E. faecium and up to 10 log CFU/ml of a six-serotype composite of Salmonella and subjected to IPAQuat-CO[subscript]2 sanitation treatments using exposure times of 30 s, 1 or 5 min. After sanitation treatments, wet coupons were swabbed for post-treatment survivors. Preliminary experiments included coupons which were soiled with a flour and water solution prior to inoculation and subsequent sanitation treatments. For the main study, inoculated surfaces were soiled with a breadcrumb flour blend and allowed to sit on the lab bench for a minimum of 16 h before sanitation. Preliminary results showed that IPAQuat-CO[subscript]2 sanitizing system was effective in reducing approximately 3.0 logs of E. faecium and Salmonella from clean and soiled surfaces after 1 min exposure but higher initial inoculum levels were needed to demonstrate >5 log reductions. For the main study, pre-treatment Salmonella populations were approximately 7.0 log CFU/25 cm[superscript]2 and post-treatment survivors were 1.3, < 0.7 (detection limit), and < 0.7 log CFU/25 cm[superscript]2 after 30 s, 1 or 5 min sanitizer exposures, respectively, for both clean and soiled surfaces. Treatment with IPAQuat-CO[subscript]2 sanitation system using 30 s sanitizer exposures resulted in 5.7 log CFU/25 cm[superscript]2 reductions whereas, greater than 6.0 log CFU/25 cm[superscript]2 reductions were observed for sanitizer exposures of 1 and 5 min. The IPAQuat-CO[subscript]2 sanitation system reduced 6 logs CFU/25 cm[superscript]2 of Salmonella with sanitizer exposure times of at least 1 min. The IPAQuat-CO[subscript]2 system would, therefore, be an effective sanitation system to eliminate potential contamination from Salmonella on food contact surfaces and have application in facilities that process dry ingredients or low-moisture products.

Master of Science / Food Science Institute / Weiqun Wang / According to the Centers for Disease Control and Prevention, 48% of known, single-setting foodborne illness outbreaks were caused by food consumed in restaurants. The lack of food handler training and knowledge of food safety concepts is a contributing factor to the continued occurrence of foodborne illness outbreaks. This report concerns food handler training undertaken with a goal of incorporating teaching techniques other than “stand and deliver” presentations to restaurant employees in the Kansas City, Kansas Metro area. Differing messaging concepts such as discussion, role playing, and hands-on segments were used. Training took place in classroom settings as well as commercial kitchen laboratories, including a working restaurant hot-food preparation line. Participants included restaurant owners, managers, as well as front and back of the house employees. Some had completed other food safety training in the past, while others had no formal food safety training. The food safety knowledge of the participants was determined in a pre-test administered just before the training session started, with the average score being 63%. The sessions began with a slide presentation and discussion of current best practices in safe food handling, followed by two hours of kitchen lab time, in which the participants rotated through several demonstration and practice stations. Areas of emphasis during the hands-on sessions were hand washing, cooling and reheating of food, proper thermometer use, and sanitizer use. Special focus was given to mimicking a hot food preparation line where employees had to handle potentially hazardous foods such as raw hamburger, and then work with ready-to-eat foods in the same area. The participants finished the training with a multiple-choice test (a score of 75% was required for recognition of the training), followed by a discussion of the test questions. The average score after training was 76%. At all times participants were encouraged to ask questions that would address specific challenges in their respective restaurants. Participants were given a post-training course evaluation to gauge acceptance of the training. Results showed strong appreciation and preference for the hands-on segments and the inclusion of industry experts as presenters. Overall, post-test scores increased by 13.6% compared to the pre-test scores. The improvement of test scores was significant (P<0.0001) indicating that the training was successful in training restaurant managers, owners, and employees about food safety practices.

Master of Science / Human Nutrition / Delores H. Chambers / Understanding how consumers handle poultry can highlight gaps in consumer knowledge and practice of food safety. Quantitative research provides only a partial image, whereas qualitative data is helpful in gaining a complete picture of a shopper's behaviors. The objective of this study was to determine what poultry product microbes could potentially be transferred during purchasing and home storage; using a shop-along observational technique to observe actual shopping, transporting, and storing behavior of consumers with raw poultry products. In 71% (n=97) of the situations observed there was no visible hand sanitizer or wipes in the meat section of the grocery store. Plastic bags could be found in the meat section 85% (n=97) of the time, which only 25% of shoppers (n=82) used the bag for their poultry products. During transportation, the consumer bagged the poultry separately from other products in 71% of the observations. A majority of shoppers (59%) stored poultry without using a plastic bag or other container. Overall, there needs to be an increase in food safety education on the handling of poultry during purchasing, transporting, and storage.

Doctor of Philosophy / Grain Science and Industry / Praveen V. Vadlani / Lignocellulosic biomass feedstocks are a sustainable resource required for rapid growth of bio-based industries. An integrated approach, including plant breeding, harvesting, handling, and conversion to fuels, chemicals and power, is required for the commercial viability of the lignocellulosic-based biorefineries. Optimization of conversion processes, including biomass pretreatment and hydrolysis, is a challenging task because of the distinct variations in composition and structure of biopolymers among biomass types. Efficient fermentation of biomass hydrolyzates comprising of different types of sugars is challenging. The purpose of this doctoral research was to evaluate and optimize the various processing steps in the entire the biomass value chain for efficient production of advanced biofuels and chemicals from diverse biomass feedstocks. Our results showed that densification of bulky biomass by pelleting to better streamline the handling and logistic issues improved pretreatment and hydrolysis efficiencies. Alkali pretreatment was significantly more effective than acid pretreatment at same processing conditions for grass and hardwood. The ethanol-isopropanol mixture, and glycerol with 0.4% (w/v) sodium hydroxide were the promising organic solvent systems for the pretreatment of corn stover (grass), and poplar (hardwood), respectively. None of the pretreatment methods used in this study worked well for Douglas fir (softwood), which indicates a need to further optimize appropriate processing conditions, better solvent and catalyst for effective pretreatment of this biomass. The brown midrib (bmr) mutations improved the biomass quality as a feedstock for biochemicals production in some sorghum cultivars and bmr types, while adverse effects were observed in others. These results indicated that each potential sorghum cultivar should be separately evaluated for each type of bmr mutation to develop the best sorghum line as an energy crop. Development of an appropriate biomass processing technology to generate separate cellulose and hemicellulose hydrolyzates is required for efficient 2,3-butanediol (BD) fermentation using a non-pathogenic bacterial strain, Bacillus licheniformis DSM 8785. This culture is significantly more efficient for BD fermentation in single sugar media than Klebsiella oxytoca ATCC 8724. Though K. oxytoca is a better culture reported so far for BD fermentation from diverse sugars media, but it is a biosafety level 2 organism, which limits its commercial potential.

Doctor of Philosophy / Food Science - Animal Sciences & Industry / Kelly J. K. Getty / Produce such as tomatoes, lettuce, and cantaloupes have been associated repeatedly with food outbreaks connected to various Salmonella serovars, Listeria monocytogenes, and Escherichia coli O157:H7. The aim of this research was to validate washing solutions and techniques in reducing pathogens on produce surfaces. Lettuce (25 ± 0.3g) and tomatoes were inoculated with E. coli O157:H7 and Salmonella spp., respectively. Samples were treated with tap water (TW) or a chemical wash treatment (CWT; containing citric acid) for 30, 60, or 120 s. Reduction of E. coli O157:H7 and Salmonella spp. populations on the surface of leaf lettuce and tomatoes, respectively, were greater (P<0.05) for CWT (ca. 3.0 logs) than for TW (ca. 2.3- 2.5 logs). Cantaloupes were washed with TW, 9% vinegar solution, or a commercial antimicrobial for fruit and vegetables treatment (CAFVT; containing lactic acid) for 2 min using a washing system. Cantaloupes were cut into wedges or cubes and stored at 4ºC for aerobic plate counts (APC) on days 0, 1, 3, and 6. APC populations of cubed and wedged cantaloupes were different over time (P=0.00052); cantaloupes washed with 9% vinegar solution showed the lowest APC populations after day 1 and 3 of storage. Salmonella spp. or L. monocytogenes inoculated cantaloupes were washed with CPW for 30, 60 or 120 s. Washing cantaloupes for 120 s with CPW showed greater (P<0.05) reductions of Salmonella spp. and L. monocytogenes populations (1.26 and 1.12 log₁₀ CFU/cm²) than TW (ca. 0.63 log₁₀ CFU/cm²) on cantaloupe surface. Lettuce leaves were inoculated with rifampicin-resistant E. coli surrogates and then washed with CAFVT, 5% vinegar solution or TW for 2 min with agitation (washing system) or without. Log reductions of CAFVT (2.25 log₁₀ CFU/g) were greater (P=0.0145) than those by tap water (1.34 log₁₀ CFU/g), but similar to 5% vinegar solution (2.09 log₁₀ CFU/g). Washing lettuce with continuous agitation achieved higher (P=0.0072) E. coli reductions (2.26 log₁₀ CFU/g) than without agitation (1.53 log₁₀ CFU/g). Overall, incorporation of wash solutions or agitation (washing system) in the washing process compared to TW alone reduced greater (P<0.05) APC, pathogens, or surrogates populations from lettuce, tomato, and cantaloupe surfaces.

Master of Science / Food Science Institute - Animal Sciences & Industry / Fadi M. Aramouni / Sweet potatoes are a significant crop and are popular among consumers, particularly as french fries. Because the processing steps of making white potato french fries may be detrimental to the quality of a sweet potato fry, it is important to understand the impact of processing on quality and consumer acceptability. The variety of sweet potatoes can affect the texture, appearance, and consumer preference. Peeling processes have evolved from harsh lye treatments to more quick and efficient methods such as steam peeling. Blanching is one of the most important steps because it deactivates enzymes, including polyphenol oxidase and amylases, that affect texture and appearance. While hot water blanching is used by majority of french fry manufacturers, novel techniques like microwave blanching may be similarly effective and less detrimental to the texture and nutritional composition. Time and temperature of the blanching method can affect the texture and flavor by weakening cell walls and leaching sugars. Drying of sweet potato fries prepares the product prior to frying. Drying drives moisture off and allows the starch on the surface of the fries to gelatinize. Many types of dryers, including vacuum, hot air, and fluidized bed, have been evaluated for the rate of moisture loss and final product texture. Drying should not be done too quickly because case hardening will occur and make the product have a tough and chewy bite. Frying uses oil at elevated temperatures to develop color, flavor, and a crispy external texture. The type of oil, oil temperature, and time of frying will affect the finished product attributes. Low oil temperature may lead to higher oil uptake into the sweet potato fries. Vacuum frying compared to deep fat frying can create sweet potato fries with less darkening and less oil uptake, but this method would be difficult in large scale manufacturing. Opportunities in creating high quality sweet potato french fries are directly related to consumer acceptability and manufacturing capability.

Doctor of Philosophy / Human Nutrition / Edgar Chambers IV / Understanding “why people eat what they eat” is important for improving the lives of people around the world by helping provide industrial and social solutions for people so that they may have greater pleasure and health from the foods they choose. The objectives of the research were to investigate motivations behind everyday meals and choices of different food groups using three different approaches incorporating two psychological perspectives: top-down and bottom-up. The first approach was the Eating Motivation Survey (TEMS) targeting the specific choices of foods and beverages people consumed at specific eating events (breakfast, mid-morning snack, lunch, mid-afternoon snack, dinner, and late-night snack). The second approach was the Food Choice Map (FCM) technique to explore motivations for individual food choices for all eating within a typical week. These two approaches employed the bottom-up process. The last approach used TEMS to investigate food choice directly for six eating occasions, without information about what were eaten specifically. This procedure demonstrated a top-down process because people first thought about their eating as a whole and then read through all TEMS scales to find the motivations that they consider "appropriate" for their answers. The first surveys were completed by 198 participants. The FCM interview was conducted on 100 respondents and the same respondents also participated in the last approach. Data were analyzed by Correspondence Analysis. Liking was the strongest motivation that drove people’s food choice. In addition, need and hunger, habits, price, and convenience were the other main motivations for breakfast, lunch, and dinner while health and weight control were found to be the main driving factors for mid-morning and mid-afternoon snacking. Late-night snacks were linked to pleasure and visual appeal. For dinner, people also were motivated most by variety seeking and traditional eating. Different food groups were also chosen with different motivations. Grain, pasta, meats and poultry were linked to convenience, variety seeking, traditional eating, and price while nuts, seeds, eggs and dairy were associated with need and hunger, health, and weight control. Findings from this project advanced and reinforced the knowledge about food choice and encouraged investigating food choice from different perspectives.