<p>Behavior change is not a product of knowledge alone but by the other constructs within the Theory of Planned Behavior (TPB). This includes attitude, subjective norms, and perceived behavioral control. In order to ensure positive change in food safety behavior, researchers should explore the current situation before providing the necessary resources for consumers. This can be done through consumer needs assessments which explore practices, perceptions, demographics, and more. Along with that, major health events like the COVID-19 pandemic can increase risk perceptions of consumers which may lead them to follow safe (washing hands with soap and water) and unsafe food handling behaviors (washing fruits and vegetables with soap). Information spreads quicker during this digital age and this can cause consumers to follow certain behaviors. To assess information being spread, chapter 2 includes a study assessing COVID-19-related food safety information on YouTube early on in the pandemic. Chapter 3 and 4 contain longitudinal studies that used surveys and focus groups to assess consumer food handling practices and risk perceptions throughout the pandemic. Another factor is the type of food being handled. Consumers are not aware that certain foods like pet food (Ch. 5) and raw wheat flour (Ch. 6) can cause foodborne illness. Thus, they may not be handling these types of products as carefully. It is important to communicate that these foods can also cause foodborne illness. In the case of raw wheat flour, while commercial brands provide food safety messages on the packaging, consumers have a hard time finding and understanding the messages. All the studies within this dissertation explored multiple elements that can fall under the different constructs of the TPB in the context of the different factors that affect food safety behaviors. For example, previous studies have found that risk perception may fall under the construct of attitude because human perceptions can influence how a person feels about the situation. The objective of this dissertation is to explore different consumer food safety needs and explore how the elements within the needs assessments feeds into the TPB. With this information, researchers can advance the use of the TPB and researchers and food safety educators can ensure positive behavior change through the TPB.</p>

Doctor of Philosophy / Department of Grain Science and Industry / Yong Cheng Shi / To realize the full potential of waxy wheat flours in food applications, six advanced hard waxy wheat lines were studied. Pasting properties of waxy wheat flours as well as factors governing the pasting properties were investigated. Waxy wheat starch granules swelled more extensively and were more prone to α-amylase degradation than normal wheat starch. A combination of endogenous α-amylase activity and protein matrix contributed to a large variation of pasting properties of waxy wheat flours. Bi-axial extension properties classified dough from waxy wheat as in-elastic. Waxy wheat flour had higher water absorption and lower mixing time than normal wheat flour. Waxy wheat starch affected protein hydration but not protein extractability after optimum dough mixing. Presence of some non-protein free thiol contents and some gliadins acting as chain terminators could be the underlying reasons for waxy wheat flours producing slack dough. In an effort to improve functionality of waxy wheat flours, hydro-thermal processing was used. Two temperatures (140 and 160°C), three moisture contents (0, 12.4 and 20%), and four exposure times (0, 5, 15, 30 and 60 min) were employed. Hydrothermal processing resulted in non-cohesive waxy wheat flours with high viscosity and greater acid stability than native waxy wheat flour. A closer investigation revealed the possible role of endosperm proteins in improving pasting properties of waxy wheat flours. Upon thermal processing, waxy wheat flours demonstrated a long hydration time before forming dough. Heating decreased protein solubility while no changes in starch molecular weight distribution were observed. Our results indicate that hydro-thermal processing results in increased starch protein interaction. As part of application of waxy wheat, bread was baked by replacing normal wheat flour with two hard waxy wheat flours at 15, 30, and 45% levels. Substitution with waxy wheat flour resulted in higher loaf volume and softer loaves. However, substitution at > 30% resulted in excessive post-bake shrinkage and a ‘key-hole’ shape with an open crumb structure. Bread crumb microstructure indicated a loss of starch granule rigidity and fusing of starch granules. Soluble starch content was significantly higher in bread 1-day old crumb containing waxy wheat flour than in control bread.

Master of Science / Department of Grain Science and Industry / Subramanyam Bhadriraju / Heat treatment involves raising the ambient temperature of food-processing facilities such as flour mills to 50-60oC for killing stored-product insects. However, very little is known about the influence of sanitation on responses of stored-product insects to structural heat treatments. The impact of sanitation on responses of life stages of the red flour beetle, Tribolium castaneum, an economically important pest in flour mills, were investigated during three 24 h structural heat treatments of the Kansas State University pilot flour mill. Two sanitation levels, dusting of wheat flour (~0.5 g) and 2-cm deep flour (~43 g), were created in 25 plastic bioassay boxes each holding 50 eggs, 50 young larvae, 50 old larvae, 50 pupae, and 50 adults of T. castaneum in separate compartments. Five boxes were placed on each of five floors of the pilot mill during 13-14 May 2009, 25-26 August 2009, and 7-8 May 2010 heat treatments using forced air gas heaters. During the August 2009 and May 2010 heat treatments, 100 eggs or 100 adults of T. castaneum were exposed inside each 20 cm diameter by 15 cm high PVC ring placed only on first and third floors and holding 0.1 (15 g), 0.2 (38 g), 1 (109 g), 3 (388 g), 6 (937 g), or 10 (1645 g) cm deep wheat flour. Among the mill floors, first floor had lower maximum temperature. The first floor rests on a thick concrete foundation, did not get heated from both sides unlike other floors, and had poor air movement resulting in cold pockets (temperatures <50oC). Mortality of life stages was lower on first floor than other floors and adults were less susceptible than other life stages especially on first floor. In general, both these tests have shown that the mortality of T. castaneum life stages were influenced by how quickly temperatures reached 50oC, how long temperatures were held above 50oC, and the maximum temperature. Protective effects of sanitation were evident only if temperatures did not reach 50oC. However, removal of flour accumulations is essential to improve heat treatment effectiveness against all T. castaneum life stages during a 24 h treatment.

Master of Science / Department of Grain Science and Industry / Subramanyam Bhadriraju / During heat treatment, the ambient temperature of grain-processing facilities is raised to 50-60°C for at least 24 hours to manage stored-product insects. Young larvae (first instars) of the red flour beetle, Tribolium castaneum (Herbst), are the most heat tolerant stage at 50-60°C. A thermal death kinetic (TDK) model predicted survival of T. castaneum young larvae exposed to six constant elevated temperatures between 42 and 60ºC. The model is based on logarithmic survival of T. castaneum as a function of time and logarithmic reduction in larval survival as a function of temperature. The model was validated with 12 independent temperature datasets collected during heat treatments of pilot-scale and commercial grain-processing facilities. Young larval survival in plastic boxes/vials with flour was used to validate model predictions. The heating rate to 50°C from the ambient among the 12 datasets ranged from 0.9-7.8°C/h. Mean absolute deviations between observed and predicted larval survival for 10 of the 12 datasets ranged from 2.1-11.4%; it was 16.2 and 18.3% for two other datasets. The TDK model can be used to predict survival of young larvae of T. castaneum based on time-dependent temperature profile obtained at any given location during heat treatment of grain-processing facilities. In three commercial grain-processing facilities heat treatments were conducted for 24-27.7 hours using forced-air gas heaters. Temperatures attained and survival of 20 eggs, 20 young larvae, and 20 adults of T. castaneum in bioassay vials at various locations were determined. Across all three facilities, 5 out of 2720 adults in 136 vials, 1 out of 960 young larvae in 48 vials, and 0 out of 1760 eggs in 88 vials were alive at the end of the heat treatment. In each facility, the time in hours for 1% predicted survival of T. castaneum young larvae was positively related to how quickly temperatures reached 50°C, and negatively related to rate of heating to 50°C from the ambient, time above 50°C in hours, and the maximum temperature. Bioassays with T. castaneum life stages and the TDK model can be used to gauge effectiveness of facility heat treatments.

Vita. / Digitized by Kansas Correctional Industries

Call number: LD2668 .T4 1985 D73 / Master of Science

Call number: LD2668 .T4 1985 M375 / Master of Science

Call number: LD2668 .T4 1985 R422 / Master of Science

Call number: LD2668 .T4 1985 W8 / Master of Science

Master of Science / Department of Grain Science and Industry / Jon M. Faubion / This work investigated the relationship between flour age (days post-milling), storage condition (temperature), and the bread baking quality of whole wheat flour. A laboratory scale milling method was designed to mimic the particle size distribution of commercially milled whole wheat flours and the 100 g ‘pup’ loaf baking method was adapted for use with whole wheat doughs. Laboratory milled whole wheat flour (Karl 92) was subjected to a 21 day storage study at two storage temperatures (72 & -15 F) with quality (baking) and chemical (lipids) analyses conducted every three days. Parameters for quality analysis included: loaf weight, volume & specific volume, as well as slice area, cell number, wall thickness, cell diameter, elongation, and non-uniformity. Three lipid classes (glycolipids, phospholipids, and neutral lipids) were extracted and analyzed by TLC with quantification by computerized analysis of spot size and density. Results were analyzed by ANOVA. Analysis of the loaf quality data revealed no trends in volume or specific volume as a function of storage time or temperature, although values for some specific days were significantly different. Likewise, analysis of crumb characteristics revealed no consistent trends for either time or storage temperature. Again, values for some, but not all, parameters (area, brightness, wall thickness, cell diameter, and non-uniformity) were significantly different for specific days of the study. Analysis of lipids revealed no consistent trends for either time or storage temperature. However, values for some lipid classes (total glycolipids, free phospholipids, and total phospholipids) were significantly different for storage temperature, and values for total neutral lipids were significantly different for specific days of the study. Suggested future research opportunities include: using new crop wheat, increasing storage duration, performing WW flour lipid exchange studies, and using lipid profiling to identify and more closely track changes in individual lipid species.