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The development of rapid detection methods for bacterial contamination in the industrial agriculture sector is vital for improving food safety and public health. Furthermore, it is important to tailor these rapid methods for low-resource settings, because the majority of foodborne illness outbreaks occur in developing nations. Currently, the most widely used methods rely on nucleic acid testing using the polymerase chain reaction (PCR). This detection reaction provides repeatable results, is highly sensitive, and is highly specific, as it can detect a single strain within a species. However, PCR is reliant on proper sample pre-treatment to remove inhibitory contaminants which can affect downstream results, which leads to a trade-off between detection time and sensitivity of results. Rolling circle amplification (RCA) is another potential detection reaction which has the same advantages and is also better suited to low-resource settings, as it works at room temperature. This thesis reports on the development of a rapid sample preparation method that can be seamlessly integrated into simple PCR and is also well suited to low-resource settings due to the low cost and high availability of the required reagents. A modification of the hot sodium hydroxide plus tris (HotSHOT) lysis reaction was implemented to extract genomic DNA (gDNA), which was then captured onto cellulose filter paper, allowing for multiple samples to be simultaneously processed in under 30 minutes. This pre-treatment can even recover gDNA for detection from samples that would have caused complete inhibition of PCR. The calculated limit of detection (LoD) of extraction followed by simple PCR was similar to that of government-approved commercial kits, without needing a lengthy bacterial enrichment step. Improvements are needed to make this a truly quantitative detection system. Finally, our paper-based pre-treatment was integrated into an RCA reaction to detect at least 105 cells, which provides proof-of-concept for combining paper-based sample preparation with isothermal amplification of target nucleic acids. / Thesis / Master of Applied Science (MASc)

While the Canadian food supply is among the healthiest in the world, almost 4 million (1 in 8) Canadians are affected by food-borne illnesses, resulting in 11,600 hospitalizations and 238 deaths per year. Microbial pathogens are one of the major causes of foodborne sicknesses that can grow in food before or following packaging. Food distribution is an important part of the food processing chain, in which food supplies are at a higher risk of contamination due to lack of proper monitoring. Among myriad of research around biosensors, current devices focusing on packaged food monitoring, such as leakage indicators or time temperature sensors are not efficient for real-time food monitoring without separating the sample from the stock. Packaged food such as meat and juice are directly in touch with the surface of their containers or covers. Therefore, real-time sensing mechanisms, installed inside the food packaging and capable of tracing the presence of pathogens, are of great interest to ensure food safety. This work involves developing thin, transparent, flexible and durable sensing surfaces using DNA biosensors, which report the presence of a target bacterium in food or water samples by generating a fluorescence signal that can be detected by simple fluorescence detecting devices. The covalently-attached DNA probes generate the signal upon contact with the target bacteria with as low as 103 CFU/mL of Escherichia coli in meat and apple juice. The fabricated sensing surfaces remained stable up to several days under varying pH conditions (pH 5 to 9). In addition to detecting pathogens on packaged food or drinking bottles, these surfaces have the potential to be used for a variety of other applications in health care settings, environmental monitoring, food production chain, and biomaterials like wound dressing. / Thesis / Master of Science (MSc) / Microbial pathogens can grow in food following packaging and preceding consumption. Current biosensors are not efficient for post-packaging real-time food monitoring without separating the sample from the stock. Packaged food such as meat and juice are directly in touch with the surface of their containers or covers. Therefore, real-time sensing mechanisms, installed inside the food packaging, tracing the presence of pathogens, are much useful to ensure the food safety. Here we report on developing thin, transparent, flexible and durable sensing surfaces using DNA biosensors, which generate a fluorescence signal in the presence of a target bacterium in food or water samples. The covalentlyattached DNA probes can detect as low as 103 CFU/mL of Escherichia coli in meat, sliced apple and apple juice. The fabricated sensing surfaces remained stable up to several days under varying pH conditions (pH 5 to 9). In addition to pathogen monitoring in packaged food or drinking bottles, these surfaces are promising for a variety of other applications in health care settings, environmental monitoring, and biomaterials like wound dressing.

Made available in DSpace on 2016-08-10T10:57:43Z (GMT). No. of bitstreams: 1 ARIANDENY SILVA DE SOUZA FURTADO.pdf: 1118992 bytes, checksum: c1595cdb059a5f60820bd999c284629d (MD5) Previous issue date: 2015-11-27 / The aim goal is to know the frequency, distribution, development and monitoring of the factors associated to the excess weight and chronic non-communicable diseases (NCDs) is essential to qualify policies and surveillance and health promotion actions for the execution of the Care Policy Health and Safety of the Federal Civil Servants (PASS). This study aimed to analyze the association between risk factors for NCDs and food consumption with excess weight in federal civil servants. Transversal population-based study which data collection was carried out between September- November 2014, at the rectory and the 10 campuses of the Federal Institute of Goiás (IFG) in the capital and provincial cities of Goiás. The sample was stratified by campus and professional category. Were collected through an electronic questionnaire the following variables: weight and height to calculate BMI; office; sex; age; body perception (silhouette of scale); frequency of physical exercise; dietary intake of sweets, fried foods, legumes - vegetables, soft drinks, canned foods, sausages and place of meals. The qualitative variables were expressed as absolute and relative frequencies and quantitative variables with mean and standard deviation. Poisson regression was used to examine bivariate and multivariate. The overweight (BMI&#8805;30,0Kg - m2) was considered the outcome and other variables were considered independent. Results: Were interviewed 429 servers, with 55.7% technical administrators and teachers 44.3% with a mean age of 36.3 ± 9.2 years, 59.7% were women, 68.8% had less than 40 years and 69.0% were sedentary. About the nutritional status, 55.0% were not overweight (BMI), but 74.8% (n = 321) were perceived with overweight (silhouette of scale). Women had lower prevalence of overweight (67.8%) than men (32.2%), p <0.000. Women also follow more the healthy eating recommendations for frying 72.4% (p <0.003) and vegetables 63.8% (p <0.033), soft drinks, 70.7% (p <0.000) and built-in 68.1 % (p <0.028) than men. Were associated with being overweight: be teaching (OR = 1.325; p = 0.011), male gender (RP = 1.401; p = 0.002), be more than 40 years of age (RP = 1.357; p = 0.004), and being sedentary (RP = 1.310; p = 0.009) and having meals outside the home (RP = 1.310; p = 0.044). Conclusion: The factors associated with excess weight were: to be teaching, male, age less than 40 years, being sedentary and eat meals outside the home. / Conhecer a frequência, a distribuição, a evolução e o monitoramento dos fatores associados ao excesso de peso e às doenças crônicas não transmissíveis (DCNT) é fundamental para qualificar as políticas e ações de vigilância e promoção da saúde em prol da efetivação da Política de Atenção à Saúde e Segurança do Trabalho do Servidor Público Federal (PASS). Este estudo teve como objetivo analisar a associação entre os fatores de risco para as DCNT e o consumo alimentar com o excesso de peso em servidores públicos federais. Estudo transversal de base populacional cuja coleta de dados foi realizada no período de setembro a novembro de 2014, na reitoria e nos 10 campus do Instituto Federal de Goiás (IFG) na capital e cidades do interior de Goiás. A amostra foi estratificada por campus e categoria profissional. Foram coletadas por meio de questionário eletrônico as seguintes variáveis: peso e altura referidos para o cálculo do IMC; cargo; sexo; idade; percepção corporal (escala de silhueta); frequência da prática de exercício físico; consumo alimentar de doces, frituras, legumes-verduras, refrigerantes, enlatados, embutidos e local de realização das refeições. As variáveis qualitativas foram apresentadas com frequências absolutas e relativas; e as variáveis quantitativas, com média e desvio padrão. A Regressão de Poisson com ajuste robusto de variância foi utilizada nas análises uni e multivariada. Para o excesso de peso (IMC&#8805;30,0Kg-m2) foi considerado o desfecho; já as demais variáveis foram consideradas independentes. Resultados: Foram entrevistados 429 servidores, sendo 55,7% técnico-administrativos e 44,3% docentes com idade média de 36,3±9,2 anos, 59,7% eram mulheres, 68,8% tinham menos que 40 anos e 69,0% eram sedentários. Quanto ao estado nutricional, 55,0% não apresentaram excesso de peso (IMC), mas 74,8% (n=321) percebiam-se com excesso de peso (escala de silhueta). As mulheres tiveram menor prevalência de excesso de peso (67,8%) que os homens (32,2%), p<0,001. As mulheres também seguem mais as recomendações da alimentação saudável para frituras 72,4% (p<0,003), legumes e verduras 63,8% (p<0,033), refrigerantes 70,7% (p<0,001) e embutidos 68,1% (p<0,028) do que os homens. Associaram-se ao excesso de peso: ser docente (RP= 1,325; p=0,011), sexo masculino (RP=1,401; p=0,002), ter mais que 40 anos de idade (RP=1,357; p=0,004), e ser sedentário (RP=1,310; p=0,009) e realização das refeições fora de casa (RP=1,310; p=0,044). Conclusão: Os fatores associados ao excesso de peso foram ser docente, do sexo masculino, idade igual ou superior a 40 anos, ser sedentário e fazer as refeições fora de casa.