Abstract. This study explored the steps of food preparation, related handwashing opportunities, current practices, and community perceptions regarding foods at high-risk of contamination such as mashed foods and salads. In three rural Bangladeshi villages, we collected qualitative and observational data. Food preparation was a complex and multistep process. Food preparation was interrupted by tasks that could contaminate the preparers' hands, after which they continued food preparation without washing hands. Community members typically ate hand-mixed, uncooked mashed food and salad as accompaniments to curry and rice at meals. Hand-mixed dried foods were mostly consumed as a snack. Observers recorded handwashing during preparation of these foods. Among 24 observed caregivers, of 85 opportunities to wash hands with soap during food preparation, washing hands with soap occurred twice, both times after cutting fish, whereas washing hands with water alone was common. A simple and feasible approach is promotion of handwashing with soap upon entering and re-entering the food preparation area, and ensuring that everything needed for handwashing should be within easy reach.

Background: Contaminated complementary foods are associated with diarrhea and malnutrition among children aged 6 to 24 months. However, existing complementary food safety intervention models are likely not scalable and sustainable. Objective: To understand current behaviors, motivations for these behaviors, and the potential barriers to behavior change and to identify one or two simple actions that can address one or few food contamination pathways and have potential to be sustainably delivered to a larger population. Methods: Data were collected from 2 rural sites in Bangladesh through semistructured observations (12), video observations (12), in-depth interviews (18), and focus group discussions (3). Results: Although mothers report preparing dedicated foods for children, observations show that these are not separate from family foods. Children are regularly fed store-bought foods that are perceived to be bad for children. Mothers explained that long storage durations, summer temperatures, flies, animals, uncovered food, and unclean utensils are threats to food safety. Covering foods, storing foods on elevated surfaces, and reheating foods before consumption are methods believed to keep food safe. Locally made cabinet-like hardware is perceived to be acceptable solution to address reported food safety threats. Conclusion: Conventional approaches that include teaching food safety and highlighting benefits such as reduced contamination may be a disincentive for rural mothers who need solutions for their

Mathematical models used to simulate the water quality and the processes of self-purification of water bodies are important tools to support effective water resource management. The objective of this study was to evaluate the impact of organic pollution on water quality and the assimilative capacity of organic matter in the Ribeirão Vermelho stream situated in the city of Lavras in Minas Gerais. The deoxygenation rate (K 1 ) and reaeration (K 2 ) were determined and tested in three segments of the Ribeirão Vermelho over two seasons (summer and winter). The purification process simulation was performed using the StreeterPhelps model. The highest K 1 and K 2 values occurred during the winter period which was characterized by lower flows. Simulation of the dissolved oxygen profile and biological oxygen demand fitted the model well, indicating the prevalence of carbonaceous deoxygenation due to nitrification and also demonstrating the importance of natural reaeration as part of the purification process. Different response was observed during the winter, in which the high primary productivity values stood in the reaeration process stream. Biological oxygen demand values did not meet the limits recommended by the Resolution of the Ministry of the Environment 357/2005 throughout the river system and the entire study period. In conclusion, the Ribeirão Vermelho is unable to self-purify along its entire length, and water quality is influenced by effluent discharge which intensifies degradation.Keywords: effluent release, Streeter Phelps models, water quality.Coeficiente de desoxigenação, reaeração e potencial de auto purificação de um ribeirão urbano RESUMOOs modelos matemáticos utilizados para simular a qualidade da água e o processo de autodepuração de corpos d'água são importantes ferramentas de auxílio à gestão dos recursos hídricos. Assim, o objetivo deste trabalho foi avaliar o impacto da poluição orgânica na qualidade da água e a capacidade de assimilação da matéria orgânica no Ribeirão Vermelho. Para essa finalidade, foi desenvolvido e testados os coeficientes de desoxigenação (K 1 ) e reaeração (K 2 ), em três trechos e em dois períodos distintos (verão e inverno). Os maiores valores de K 1 e K 2 foram obtidos durante o inverno, onde foram registrados as menores vazões. A simulação do processo de autodepuração foi realizada com o uso do modelo de Streeter-Phelps. A simulação do perfil de OD e DBO no verão apresentou calibração aceitável, tendo em vista a otimização dos coeficientes, evidenciando a prevalência da desoxigenação por demanda carbonácea sobre a nitrificação e a importância da reaeração natural no processo de autodepuração. Comportamento diferente foi observado no inverno, no qual os altos valores de produtividades sobressaíram no processo de reaeração no ribeirão. Apenas o parâmetro demanda bioquímica de oxigênio não respeitou os limites preconizados pela Resolução do Ministério do Meio Ambiente 357/2005, tendo ficado em toda a extensão do rio e, em ambos períodos, fora da regulamentação. Des...

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doi: 10.3329/bjms.v8i1.3181Bangladesh Journal of Medical Science Vol.8 No. 1-2; 2009 4