Bacterial responses to environmental stresses may be easily observed and predicted under controlled laboratory conditions. However, realistic conditions encountered during manufacturing, in retail or in households may cause unpredicted responses of spoilage or pathogenic bacteria. Therefore it is essential to identify and understand the microbial dynamics under such conditions. The overall aim of the present study was to simulate the most common environmental conditions and consumer-style practices during storage or preparation of Ready-to-Eat (RTE) and Ready-to-Cook (RTC) products in the domestic environment, and predict the microbial dynamics which may deteriorate the quality or compromise the safety of these foods. Aiming to develop a unified mathematical model for the prediction of the growth of the specific spoilage microorganisms (SSOs), the spoilage pattern of three RTE acidic spreads of low pH was described in relation to microbial, physicochemical and molecular changes during storage. Results showed that the spoilage profile of the products was primarily affected by the initial pH and the storage temperature, despite the differences in their formulation. These findings enabled the assessment of two unified models (polynomial and Ratkowsky) for the prediction of the growth of lactic acid bacteria (LAB; SSOs) in such acidic spreads, using only the initial pH, the concentration of undissociated acetic acid and the storage temperature. The models were validated under realistic conditions in household refrigerators. Despite the abrupt fluctuations of the temperature during validation procedure, they both were able to adequately predict the growth of LAB in the spreads. However, the initial contamination level was proved to be necessary and crucial for the accurate prediction of microbial dynamics. The time-temperature profiles of the validation procedure revealed that the suggested storage conditions were not followed promptly and, therefore, concerns were raised on the effect of such consumer mishandlings on the safety of foods. Therefore, the responses of Salmonella spp. and Escherichia coli O157:H7 to the stresses encountered during frozen storage, thawing and cooking of ground beef, simulating typical scenarios followed by the consumers, were evaluated. The results revealed that the guidelines issued by the food safety authorities lack of some specific points that may affect the safety of the final product, such as the duration of frozen storage and the method of cooking. In particular, it was found that the heat resistance of E. coli O157:H7 was likely increased after long term frozen storage, while cooking in pan-grill did not ensure the safety of the final product, even when cooked at the suggested temperature. As shown in the first study, the initial contamination level played a significant role on the predictions of the models and further on the shelf-life of the products. Therefore, the dynamics of realistically low initial populations of Listeria monocytogenes and Salmonella Typhimurium versus higher levels of the pathogens (such those used during in vitro trials) in RTE fresh-cut salads were compared. In addition, any potential uncertainty sources for the growth potential of the pathogens in broth-based simulations were investigated. Results showed that the growth variability of low inocula is highly affected by the marginal storage temperatures, the indigenous microflora and the availability of nutrients. Because of this, growth from low populations showed the likelihood to exceed the growth derived from unrealistically high inocula, suggesting that ―fail-dangerous‖ implications may derive from such challenge tests. Data derived from this part were compared with broth-based simulations and the results showed that high uncertainty should be expected when extrapolating such predictions from low initial populations in fresh-cut salads, due to the various factors affecting the microbial growth on a real food, which are (inevitably) ignored by broth-based models. Overall, the present Thesis highlights the significant impact of consumer mishandlings on the food safety and quality of foods and contributes to the identification of unpredicted potential risk origins in the domestic environment.

published_or_final_version / Architecture / Master / Master of Architecture

Food is a fundamental necessity of life. However, millions of Americans do not have access to adequate food and are considered to be "food insecure." Research has shown that low-income individuals have limited food preparation skills and low levels of self-efficacy to prepare healthy meals, further complicating their food situations. The purpose of this pilot study was to determine the effectiveness of a community cooking demonstration at increasing self-efficacy to prepare healthy meals with limited resources. Twenty-three low-income adults participated in the intervention and completed a pre- and post-test assessment to measure changes in self-efficacy to cook, as well as changes in general food and nutrition knowledge. Results indicated that although there were no significant improvements in participants’ self-efficacy to prepare healthy meals (39.3 ± 11.3 vs. 44.5 ± 9.1; t=1.76, p=0.25), subjects did experience significant gains in knowledge related to the MyPlate food guide (1.2 ± 0.5 vs. 1.8 ± 0.8; t=2.82, p=0.01) and basic food safety (0.7 ± 0.9 vs. 2.5 ± 1.0: t=6.05, p<0.001). Increased knowledge is a critical building block toward behavior change and increased self-efficacy. / Department of Family and Consumer Sciences

This study was conducted to examine the food perceptions, purchasing, preparation, and consumption behaviors of female SNAP participants in East Central Indiana. Twenty participants were interviewed, and interviews were transcribed and compiled in order to identify patterns. Participants were primarily white, had at least a high school education, were food-secure, and 85% were either overweight or obese. Results indicated that the participants interviewed in this study had limited opportunities to participate in food and nutrition education courses unless approached by community agencies. Participants indicated they purchased a large variety of healthy and unhealthy food items from a wide array of grocers. A portion of the participants participated in EFNEP courses (n=4), WIC education (n=7), or conducted self-research (n=9). These participants indicated they retained knowledge by participating in these methods of education. Although participants expressed the desire to exhibit healthy eating behaviors, such as examining food labels, they also indicated they did not understand how to utilize the information to make healthy food choices. Results indicated all participants in SNAP would benefit from food and nutrition education courses that focus on SNAP benefit budgeting, meal planning that includes more fruits and vegetables, low-fat food items, and leaner cuts of meat, and physical activity. Practitioners and SNAP officials should be encouraged to coordinate efforts to make participants aware of educational opportunities in order to improve overall health outcomes. / Department of Family and Consumer Sciences

Despite the huge national energy resources, many Nigerians do not have access to high quality, modern energy services. For those with access, energy supply lacks reliability, especially in the case of liquefied petroleum gas (LPG). Hence this research considers the possibility of enhancing the household use of LPG. It analyzes the factors affecting the current demand and supply. Salient features of the LPG supply and distribution system were also discussed. On the basis of the existing situation, barriers of increasing LPG use, in particular, the problems regarding affordability, priCing, government poliCies, safety, transportation and distribution were analyzed and identified statistically using the chi-square statistical method as a tool. Finally, on the basis of the challenges identified, suggestions and recommendations were made regarding the policies through which the problems could be overcome. Furthermore, a model was developed and tested for an effective marketing strategy of LPG in Warri Nigeria. ii / Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2009.

Despite the huge national energy resources, many Nigerians do not have access to high quality, modern energy services. For those with access, energy supply lacks reliability, especially in the case of liquefied petroleum gas (LPG). Hence this research considers the possibility of enhancing the household use of LPG. It analyzes the factors affecting the current demand and supply. Salient features of the LPG supply and distribution system were also discussed. On the basis of the existing situation, barriers of increasing LPG use, in particular, the problems regarding affordability, priCing, government poliCies, safety, transportation and distribution were analyzed and identified statistically using the chi-square statistical method as a tool. Finally, on the basis of the challenges identified, suggestions and recommendations were made regarding the policies through which the problems could be overcome. Furthermore, a model was developed and tested for an effective marketing strategy of LPG in Warri Nigeria. ii / Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2009.

The main aim of this study is to define the cooking activity spaces in Burgaz at 4th Century B.C. by carrying out statistical analysis of artefacts come from floor levels. In this study the distribution of artefacts and the associations of these distributions with architectural remains are examined rather than architectural features. In order to defining cooking activity spaces, the spatial distribution of cooking wares and utilities were taken into consideration. The distributions of cooking wares were tried to associate with ashy areas that can be related to cooking activities. In this study, the spatial analysis of archaeological artefacts assemblages that found in four well preserved houses from NE Sector revealed during the excavations of Burgaz (1993-2003) was carried out and the space usage, especially cooking spaces, were identified in these houses.

Across Australia and other developed nations, morbidity and mortality follows a socioeconomic gradient whereby the lowest socioeconomic groups experience the poorest health. The dietary practices of low socioeconomic groups, which are comparatively less consistent with dietary recommendations, have been thought to contribute to the excess morbidity and mortality observed among low socioeconomic groups, although this phenomenon is not well understood. Using a socioecological framework, this thesis examines whether the local food retail environment and confidence to cook contribute to socioeconomic differences in fruit and vegetable purchasing. To achieve this, four quantitative analyses of data from two main sources were conducted. The food retail environment was examined via secondary analysis of the Brisbane Food Study (BFS) and confidence to cook was examined in a cross-sectional study designed and carried out by the author. The first three manuscripts were based on findings from the BFS. Briefly, the BFS was a multilevel cross-sectional study, designed to examine determinants of inequalities, that was conducted in Brisbane in the year 2000. A stratified random sample was taken of 50 small areas (census collection districts, CCDs) and 1003 residents who usually shopped for their households were interviewed face-to-face using a schedule that included a measure of fruit and vegetable purchasing and three socioeconomic markers: education, occupation and gross household income. The purchasing measure was based on how often (never, rarely, sometimes nearly always or always) participants bought common fruits and vegetables for their households in fresh or frozen form, when in season. Food shops within a 2.5 km radius of the CCDs in which survey respondents lived were identified and audited to determine their location, type, their opening hours, and their price and availability of a list of food items. The first publication demonstrated there was minimal to no difference in the availability of supermarkets, greengrocers and convenience stores between areas that were most and least disadvantaged, in terms of the number of shops, distance to the nearest shop, or opening hours. Similarly, the second publication showed the most disadvantaged and least disadvantaged areas had no large or significant difference in the price and availability of fruits and vegetables within supermarkets, greengrocers and convenience stores, but small differences were consistently apparent, such that on average, low socioeconomic areas had lower prices but also lesser availability than more advantaged areas. The third submitted manuscript presents results of multilevel logistic regression analyses of the BFS data. While there were some associations between environmental characteristics and fruit and vegetable purchasing, environmental characteristics did not mediate socioeconomic differences in purchasing the fruit and vegetable items since there was no substantial socioeconomic patterning of the price or availability of fruits and vegetables. The fourth submitted manuscript was based on the cross-sectional study of cooking skills. A stratified random sample of six CCDs in Brisbane was taken and 990 household members ‘mostly responsible’ for preparing food were invited to participate. A final response rate of 43% was achieved. Data were collected via a self-completed questionnaire, which covered household demographics, vegetable purchasing (using the same measure employed in the BFS for continuity), confidence to prepare these same vegetables, and confidence to cook vegetables using ten cooking techniques. Respondents were asked to indicate how confident they felt (ranging from not at all- to very- confident) to prepare each vegetable, and to use each technique. This fourth study found respondents with low education and low household income had significantly lower confidence to cook than their higher socioeconomic counterparts, and lower confidence to cook was in turn associated with less household vegetable purchasing. Collectively, the four manuscripts comprising this thesis provide an understanding of the contribution of food accessibility, affordability and cooking skills to socioeconomic differences in fruit and vegetable purchasing, within a socioecological framework. The evidence provided by this thesis is consistent with a contributory role of confidence to cook in socioeconomic differences in fruit and vegetable purchasing, but is not definitive. Additional research is necessary before promoting cooking skills to improve population nutrition or reduce nutritional inequalities. An area potentially useful to examine would be how cooking skills integrate with psychosocial correlates of food and nutrition, and socioeconomic position. For example, whether improvement of cooking skills can generate interest and knowledge, and improve dietary behaviours, and whether a lack of interest in food and nutrition contributes to a lack of both fruit and vegetable consumption and cooking skills. This thesis has demonstrated that an inequitably distributed food retail environment probably does not contribute to socioeconomic variation in fruit and vegetable purchasing, at least in contemporary Brisbane, Australia. Findings are unlikely to apply to other time periods, rural and regional settings, and perhaps other Australian cities as residential and retail development, and the supply and pricing of produce vary substantially across these dimensions. Overall, the main implication for public health is that interventions targeting the food supply in terms of ensuring greater provision of shops, or altering the available food and prices in shops may not necessarily carry a great benefit, at least in major cities similar to Brisbane. Future studies of equitable food access may need to look beyond mapping the distribution of shops and prices, perhaps to more personal and subjective facets of accessibility and affordability that incorporate individuals’ perceptions and ability to access and pay for foods.

It is reported that cooking can generate many kinds of airborne pollutants,which pose serious threats to human health. Kitchen range-hood is themost effective and popular equipment to exhaust the airborne pollutants,including smoke and oil particle in people’s daily life. The lack of astandardized and overall approach to test and evaluate range-hood makesboth consumer and some manufacturers confused. For these reasons,Lawrence Berkeley National Laboratory published a report, whichshowed the results of their elaborate experiment and some conclusion.However, they also pointed out that due to the limitation of the apparatus,some of the results are not reliable.Therefore, this project established a numerical model in Fluent toinvestigate the pollutant removal performance. Many attempts had beenmade before a validated numerical model was accomplished because aproper model needs the balance between iteration time and resultaccuracy. The validation part is presented in the literature. The captureefficiency curve of the numerical model and one of experiments show agood agreement at the low power input. Some conclusions are drawn onhow power inputs and height affect the capture efficiency, respectively.Dimensionless analysis is done to find a general characteristic curve forevaluating the removal performance of a particular range-hood. / Det rapporteras att matlagning kan generera många typer av luftburnaföroreningar, vilket utgör allvarliga hot mot människors hälsa.Köksfläkten är den mest effektiva och populära utrustningen för attventilera ut luftburna föroreningar, inklusive rök och oljepartiklar imänniskors dagliga liv. Bristen på ett standardiserat och övergripandetillvägagångssätt för att testa och utvärdera köksfläktar ställer bådekonsumenten och vissa tillverkare i okunskap. Av dessa skäl publiceradeLawrence Berkeley National Laboratory en rapport, som visade resultatenav deras utarbetade experiment och en slutsats. Men de påpekade ocksåatt på grund av begränsningen av utrustningen är några av resultaten intehelt tillförlitliga.Därför fastställde detta projekt en numerisk modell i Fluent för attundersöka avlägsnandet av föroreningar. Många försök hade gjorts innanen validerad numerisk modell uppnåddes, eftersom en riktig modellbehöver balansen mellan iterationstid och resultatnoggrannhet.Valideringsdelen presenteras i litteraturen. Effektkurvan för dennumeriska modellen och ett av experimenten visar en godöverensstämmelse vid låg effektinmatning. Några slutsatser dras av hurkraftingångar och höjd påverkar upptagningseffektiviteten.Dimensionslös analys görs för att hitta en generell karaktäristisk kurvaför att utvärdera avlägsnande av prestanda för ett viss köksfläkt.

Zugl.: Düsseldorf, Univ., Diss., 2005