Master of Science / Department of Agricultural Economics / Vincent R. Amanor-Boadu / Changes in consumer preferences have frequently created markets for new products. Recently these changes in consumer preferences have been brought on by people we term as "ethical consumers." These consumers demand is driven by the extrinsic characteristics of the products they purchase. In this thesis we analyze consumer demand theory for its application to ethical consumers, we determine the demographic factors that influence the emergence of the ethical consumer, and we classify ethical consumers by the categories of extrinsic factors influencing their consumption decisions. We explore the theory of Abraham Maslow's Hierarchy of Needs. Our theory tells us that as people reach the self-actualizing stage in Maslow's Hierarchy they have the income and education to make their purchase decisions based on how it will effect others and the environment. We found higher income levels and educational attainment to be characteristics of our ethical consumer. We also found that the reasons these ethical consumers are purchasing ethical products fall into five categories, environment, social justice, biodiversity, and religious. This paper develops a theory on Ethical consumers, determining the demographics of the consumer and their motivations for their ethical purchases. Future research may look at using this information to create a demand theory for ethical consumers.

The influence of increasing hydrolyzed protein content on the microstructure and hardness of high protein nutrition bars was investigated to determine the mechanism of hardening during storage. Bars with various hydrolyzed protein levels were manufactured using differing ratios of 0, 25, 50, 75, 100% (wt. /wt.) of partially hydrolyzed whey protein isolate (HWPI) to an intact (non-hydrolyzed) whey protein isolate (WPI) which made up approximately 38% of the total bar composition. High fructose corn syrup (HFCS) (42%) and vegetable shortening (20%) constituted the rest of the ingredients. Accelerated aging was performed by storing bars at 32 ºC for 36 d with analysis being performed every 7 d starting at d 2. Hardness was measured as the peak force to penetrate into the bars 8.5 mm using a 45º chisel blade. Microstructure was examined using confocal scanning microscopy with staining for protein and fat. The level of HWPI affected both hardness and microstructure of the bars. Bars that developed the most hardness, with hardness values of 87.6 x 102 g-force and 97.2 x 102 g-force, were those that had no added HWPI or only 25% HWPI (P < 0.05). Bars with 100% of the protein as HWPI were softest with a value of 24.6 x 102 g-force (P< 0.05) and these bars had a microstructure showing a two-phase separation of fat from the aqueous phase containing protein and sugars. The bars that exhibited severe bar hardening had a three-phase separation of the fat, protein, and sugar. The gradual separation of the protein from the sugars into two distinct phases is proposed as the mechanism causing hardening in high protein nutrition bars. The influence of different carbohydrate sources on water activity, Maillard browning, hardness, and microstructure was then investigated. Bars were formulated using either WPI or HWPI with either 70% HFCS or 70% sorbitol syrup as carbohydrate source. This resulted in four bar types, which were then aged at an accelerated rate through storage at 32 ºC and analyzed again every 7 d. Color and water activity were measured as well as hardness and the microstructure was again observed using confocal microscopy. Changing the carbohydrate component of the bars from HFCS to sorbitol syrup had a large effect on the amount of Maillard browning, no effect on the aw, and a slight effect on bar hardening and microstructure while using HWPI instead of WPI had a slight effect on browning, an effect on water activity, and a large effect on bar hardening and microstructure. The carbohydrate effect on bar hardening was not to the same degree as using HWPI. Using sorbitol with WPI reduced hardness after 35 d at 32 ºC by 25% while replacing WPI with HWPI reduced hardness by 55%. When using HWPI both the HFCS and sorbitol, bars remained soft (i.e. hardness <500 g-force) through d 27, with the HFCS increasing in hardness (P < 0.05) by d 35.

No description available.

Increasing underrepresented minority youth (URMY) engagement in STEM education remains at the forefront of our Nation's educational battle. The aim of this study was to create, implement, and evaluate the impact of innovative food science and technology (FST) lesson plans on URMY engagement in, and attitudes towards science, and their awareness of the field of FST. The 2011 United States census recalls that URMY make up only 13.3% of the STEM workforce. This study identifies URMY as individuals representing one or more of the following demographics: Low income, African American, Latino(a) American, and Indian American. Eight 5th-6th grade youth participated in a seven-week program, The Enliven Program (TEP), which is a STEM education program created for the purpose of this. The Enliven Program focuses on youth engagement in science learning through the implementation of a FST curriculum. The lessons delivered in TEP utilized the Biological Sciences Curriculum Study (BSCS) 5E instructional model as its foundation. This model focuses on five phases of student centered learning: engagement, exploration, explanation, elaboration, and evaluation. Data was collected using a fixed-mixed methods design. A qual-quan approach was employed to measure youths' positive behavioral and cognitive engagement in science learning. Measures of positive behavioral and cognitive engagement demonstrated that youth were positively behaviorally and cognitively engaged in the science learning activities. Furthermore, relationship building played an instrumental role in maintaining youth participants' positive attitudes towards and engagement in TEP activities. The results display an overall increase in youth's desire to do science and self-concept in science. / Master of Science in Life Sciences / The aim of this interdisciplinary study was to create innovative teaching methods, based on existing food science and technology (FST) curricula, with a broader goal of increasing engagement in science among underrepresented minority youth (URMY). In this study, the sample of URMY were individuals, in the 5^th-6^th grade, representing one or more of the following demographics: Low income, African American, Latino(a) American, American Indian. Eight youth participated in a seven-week program, The Enliven Program (TEP), a STEM education program, which focused on implementing engaging science activities, with the purpose being to examine engagement of youth in science learning. This program utilized the Biological Science Curriculum Study (BSCS) 5E educational model as its foundation, forming each lesson using a 5E lesson plan template. This model focuses on five phases of student centered learning: engagement, exploration, explanation, elaboration, and evaluation. Each lesson focused on the implementation of FST curriculum through the use of food and culinary arts techniques. In TEP, youth also had the opportunity to interact with professionals in the field of food science and technology. Measures of positive behavioral and cognitive engagement demonstrated that youth were positively behaviorally and cognitively engaged in the science learning activities. Furthermore, building rapport and a relationship with youth as a group, and on an individual level, was essential in maintaining youth participants’ positive attitudes towards and engagement in TEP activities. Results reveal an overall increase in youth’s desire to do science and self-concept in science.

Doctor of Philosophy / Food Science Institute -- Animal Science & Industry / J. Scott Smith / A rapid direct solvent extraction method for the extraction of 2-dodecylcyclobutanone (2-DCB) in irradiated beef using acetonirile was developed and evaluated. The 2-DCB in commercially irradiated ground beef patties was extracted with n-hexane by using a Soxhlet apparatus or with acetonitrile via direct solvent extraction. The hexane and the acetonitrile extracts were evaporated to dryness. Then, the fat in the hexane extract was removed with filtration by standing at -20 °C after the addition of a mixture of ethylacetate and acetonitrile. The defatted extract as well as the acetonitrile extract were purified with a 1 g silica cartridge and was injected into a gas chromatography-mass spectrometry (GC-MS). The 2-DCB concentration in irradiated patties was 0.031 ± 0.0026 ppm (n = 5) for the Soxhlet method and 0.031 ± 0.0025 ppm (n = 10) for direct solvent extraction. The effect of low-energy X-rays on the formation of 2-DCB was investigated in frozen ground beef. Beef patties (85/15) were irradiated by low-energy X-rays and gamma rays at 3 targeted doses of 1.5, 3.0, and 5.0 kGy. The 2-DCB was extracted with n-hexane by using a Soxhlet apparatus and analyzed by GC-MS. There was no significant difference in 2-DCB concentration between gamma-ray- and low-energy X-ray-irradiated patties at all targeted doses. The metabolism of 2-DCB was investigated in vitro and in vivo. The incubation mixture from the in vitro study was extracted with n-hexane by using a Soxhlet apparatus and injected into a GC-MS). The hexane extract from the in vitro study and of rat feces was also derivatized with a silylation reagent and injected into a GC-MS. The average percentage of 2-DCB recovered from the test incubations (2-DCB with S9 and NADPH) was 23%, compared with 50% from the controls (2-DCB in buffer). The GC-MS chromatograms of the derivatized samples showed that 2-DCB was metabolized to 2-dodecylcyclobutanol.

Master of Agribusiness / Department of Agricultural Economics / Michael W. Woolverton / The sheep dairy industry in the United States is small. Producers are concentrated in a few areas geographically with the greatest demand for sheep milk products located on the east and west coasts. The purpose of this analysis is to determine if a family-run sheep dairy located in Central Iowa could produce an annual profit of $40,000 without utilizing labor hired outside the family. Budgets were created and used to determine the revenues and costs of operating a sheep dairy, and producing and selling three different end products for sale: fluid milk, cheese and bars of soap. Microsoft Solver was used to determine the product mix that would maximize the total profit of the enterprise. The profit of the enterprise depends on a number of factors including the cost of feed, the number of ewes milked and the amount of milk each ewe produces. A maximum profit of $66,993 could be generated by selling 74% of the milk as fluid milk, 25% of the milk processed into cheese and 1% of the milk processed into soap. The diversification of products would help buffer the enterprise from volatility in the product markets. While the budgets show that this enterprise is profitable, local markets for these products must be identified and/or developed for the profits to be realized.

Master of Science / Department of Animal Sciences and Industry / Terry A. Houser / Two experiments were conducted to determine the effects of dried distillers grains with solubles (DDGS) on pork loin and fat quality. In the first experiment, 1,160 barrows (PIC) were used in a 70-d study to determine the influence of DDGS and glycerol on pork loin and fat quality attributes. Barrows were fed a corn-soybean meal based diet with the addition of selected levels of DDGS (0 or 20%) and glycerol (0, 2.5, or 5%) feed stuffs. Loins from the two heaviest pigs in each pen were removed for evaluation of pork loin and fat quality. Experiment two was a pilot study, in which eight non-pregnant sows were fed either 0 or 50% DDGS with a corn soybean meal based diet for 92-d. In the first experiment, there were no DDGS x glycerol interactions for purge loss %, instrumental color (L*a*b*), visual color, marbling score, drip loss %, visual color, pH, Warner-Bratzler shear force (WBSF), cook loss %, myofibrillar tenderness, juiciness, pork flavor intensity, connective tissue amount, and overall tenderness. There was a DDGS x glycerol interaction (P<0.03) for off-flavor intensity. Pigs fed diets with 20% DDGS had higher WBSF values, lower myofibrillar tenderness, lower overall tenderness scores, lower connective tissue scores, and had more off-flavors (P<0.05). Loin fatty acid analysis revealed an increase in palmitoleic, linoleic, and eicosadienoic acids (P<0.05) and iodine value (P<0.03) for pigs fed 20% DDGS. In the second experiment, there were no differences (P>0.64) in BW or backfat change for sows fed either 0 or 50% DDGS. No differences (P>0.23) in lipid oxidation from lean trimmings as measured by 2-thiobarbituric acid reactive substances (TBARS) assay were reported either initially or after 5 d of retail display for sows fed either 0 or 50% DDGS. As expected, lipid oxidation increased (P<0.003) as measured by TBARS assay for both treatments from d 1 to 5. Jowl fatty acid analysis revealed an increase in linoleic acid (P<0.01), total polyunsaturated fatty acids (P<0.01), and the ratio of polyunsaturated fatty acids to saturated fatty acids (P<0.03) for sows fed 50% DDGS.

Master of Science / Food Science Institute / Michael E. Dikeman / The objective was to determine the effects of needle-free injection (NF) compared with traditional needle injection (N) on microbial translocation of generic E. coli in beef strip loins. Longissimus muscles (LM) (n=5) from USDA Select carcasses were used in preliminary research to determine the optimal injection pressure required for NF injections. Seven treatments with sterile colored saline solution were administered: 1) 90 psi ; 2) 55 psi ; 3) 50 psi ; 4) 45 psi ; 5) 30 psi ; 6) 25 psi ; or 7) 20 psi . For the second portion of the experiment 15 LM were obtained and halved; the surfaces were inoculated with generic E. coli at a level of 106 CFU/cm2 (three replications of five loins). Matching halves were allocated to NF or N injection treatments with a phosphate, salt solution. Immediately after injection, two cores, 23 cm2 in area, were taken aseptically from each half. A 2-mm thick cross-sectional slice was removed from the inoculated surface of the core and labeled “surface”. Using sterile technique, the two cores from each half were sliced into cross-sectional strips at depths of 1, 3, and 5 cm. Corresponding depth measurements were combined in stomacher bags with 99 ml of peptone water and stomached. Serial dilutions were then plated. From the preliminary study, it was determined that 25 psi was the optimal pressure for NF injection based on dispersion, visual appraisal, and solution retention. Samples taken from the surface of N injected LM had lower (P < 0.05) microbial counts than NF-injected muscles (2.79 versus 3.23 log CFU/g, respectively). The 3 and 5 cm depth samples from N injection had the least (P < 0.05) microbial contamination (1.69 and 2.12 log CFU/g) compared to NF injections. Samples from 1 cm deep of N injected LM had lower (P < 0.05) (2.53 log CFU/g) microbial counts than the 1 cm samples of NF injected LM (3.04 log CFU/g). Traditional N injection resulted in approximately 0.5 log CFU/g less microbial contamination at all depths. N injection posed fewer microbial risks when compared with NF injection using these defined application settings.

Master of Public Health / Public Health Interdepartmental Program / Daniel Y.C. Fung / In the military, documenting the occurrence of foodborne illnesses is a challenge. During peacetime only about ten percent of all foodborne illnesses are reported or properly diagnosed. Between 1998 and 1999, the Army had documented over 800 cases involving food or waterborne diseases. Service members are classified as highly susceptible when they are deployed or participating in extended field training exercises. Physical and emotional stress weakens the immune system, as does fatigue. These situations can be further aggravated by soldiers taking medications and/or exposed to exotic diseases or extreme environmental conditions. Thus it is very important for the United States Army to have a very good food safety, security, and protection system in place to maintain a readily deployable force. The United States Army monitors food safety, security, and defense through an extensive network of multiple organizations within and outside the army by researching from the fields of microbiology, sociology, economics, bioterrorism, etc. This network monitors food procured by the army from the source to the consumer and maintains accountability throughout the process. This report takes a look at the multiple organizations and the various strategies entailed in implementing food safety, security, and protection within the army and the entire Department of Defense. It emphasizes on some of the strategies that can be developed and applied in civilian establishments to improve the efficiency of the establishments. Such strategies include the implementation of the Prime Vendor System and the World Wide Web directory of sanitary approved sources which help to improve the ability to monitor the food with fewer personnel and also improve security and defense through solicitations and contracts. These strategies have been so effective that they are being used not only for food but for general logistics.

Doctor of Philosophy / Department of Grain Science and Industry / Subramanyam Bhadriraju / Ludek Zurek / Feed samples and live stored-product insects from feed mills and swine farms were collected and cultured for Enterococcus spp. The mean concentration of enterococci in insect and feed were 2.7 ± 0.5 × 101 cfu/insect and 6.3 ± 0.7 × 103 cfu/g respectively. A total of 362 isolates of enterococci collected from 89 feed samples and 228 stored-product insects were identified to the species level using PCR. These isolates were represented by Enterococcus casseliflavus (53.0%), E. gallinarum (20.4%), E. faecium (16.2%), E. hirae (5.2%), and E. faecalis (5.0%). Enterococci were phenotypically resistant to tetracycline (48.0%), erythromycin (14.3%), streptomycin (16.8%), kanamycin (12.1%), ciprofloxacin (11.0%), ampicillin (3.3%), and chloramphenicol (1.1%). All isolates were susceptible to vancomycin and gentamicin. Tetracycline resistance was encoded by tetM (50.0%), tetO (15.1%), tetK (0.5%), tetS (0.2%) and other unknown tetracycline determinants. Enterococci carried virulence genes including gelatinase (gelE; 21.5%), an enterococcus surface protein (esp; 1.9%), and cytolysin (cylA; 2.2%). An aggregation substance (asa1) gene was detected in 61.0% of E. faecalis isolates. Fifty perncet of E. faecalis isolates were phenotipically tested positive for aggregation substances. Enterococci with cylA genes were hemolytic (52.0%) and with gelE genes were gelatinolytic (18.5%). The ermB gene, encoding erythromycin resistance was detected in 8.8% of the total isolates. The Tn916/1545 family of conjugative transposons was detected in 10.7% of the isolates. Laboratory experiments showed that adults of the red flour beetle, Tribolium castaneum (Herbst), fed on poultry and cattle feeds inoculated with E. faecalis OG1RF:pCF10, were able to successfully acquire enterococci and contaminate sterile poultry and cattle feeds. To assess the potential of horizontal gene transfer, conjugation assays were carried out with E. faecalis using a donor (wild strains) and recipient (E. faecalis OG1SSP) in ratio of 1:10. Only one isolate (1 out of 18 E. faecalis) could transfer tetM to a recipient using broth mating. However, filter mating assay, followed by PCR confirmation revealed that 89.0% (16 out of 18 E. faecalis) of isolates could transfer tetM to E. faecalis. Transfer ratios of transconjugant per recipients ranged from 2.6 × 10-4 to 1 × 10-9. In summary, feed (52.0%) and stored-product insects (41.6%) collected from feed mills and swine farms carried antibiotic-resistant and potentially virulent enterococci. Our study showed that T. castaneum, a pest commonly associated with feed, served as a potential vector for enterococci in the feed environment. Conjugation assays followed by PCR confirmed presence of the tetM gene on a mobile genetic element(s) such as Tn916 and may be horizontally transferred to other Enterococcus species and to other bacteria of clinical significance.