RESUMO
The production of volatile fatty acids (VFAs), intermediates in the anaerobic degradation process of organic matter from waste water, was evaluated in this work. A batch reactor was used to investigate the effect of temperature, and alkalinity in the production of VFAs, from the fermentation of industrial cassava waste water. Peak production of total volatile fatty acids (TVFAs) was observed in the first two days of acidogenesis. A central composite design was performed, and the highest yield (3400â mgâ L(-1) of TVFA) was obtained with 30°C and 3â gâ L(-1) of sodium bicarbonate. The peak of VFA was in 45â h (pH 5.9) with a predominance of acetic (63%) and butyric acid (22%), followed by propionic acid (12%). Decreases in amounts of cyanide (12.9%) and chemical oxygen demand (21.6%) were observed, in addition to the production of biogas (0.53â cm(3)â h(-1)). The process was validated experimentally and 3400â gâ L(-1) of TVFA were obtained with a low relative standard deviation.
Assuntos
Ácidos Graxos Voláteis/metabolismo , Manihot/química , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Anaerobiose , Reatores Biológicos , Ácidos Graxos Voláteis/análise , Fermentação , Concentração de Íons de Hidrogênio , TemperaturaRESUMO
Como importante fonte alimentar humana, o leite e seus derivados sem os devidos cuidados no processamento pode representar um risco à saúde pública. Apesar da legislação brasileira não permitir a comercialização de produtos sem pasteurização, inúmeros produtores alternativamente fabricam queijos e outros derivados a partir de leite cru. Visando melhorar a qualidade e apresentação dos produtos lácteos comercializados por pequenos produtores rurais na cidade de Toledo-PR, foi implantado um projeto com subsídio financeiro do município para aquisição e instalação de pasteurizadores. Com o objetivo de avaliar a qualidade microbiológica dos produtos lácteos produzidos artesanalmente na cidade, foram coletadas amostras de sete produtores de queijo e sete de creme de leite antes e após a pasteurização do leite na propriedade. Análises de Coliformes totais, fecais, E. coli e Salmonella sp. foram realizadas nos produtos em conformidade com a legislação vigente. Quanto à presença de coliformes totais, todas as amostras apresentaram contagem elevada antes da pasteurização e após; esta contagem foi considerada pouco expressiva ou nula. Quanto à presença de coliformes fecais, sete produtores (100%) de queijo e seis produtores (85,71%) de creme de leite apresentaram amostras com contagem acima do permitido pela legislação antes da pasteurização, enquanto que após a pasteurização quatro (57,14%) produtores de queijo e dois (28,57%) de creme de leite se encontraram fora dos padrões exigidos. Foi detectada a presença de E. coli em amostras de cinco produtores (71,42%) de queijo equatro (57,14%) de creme de leite antes da pasteurização e após a pasteurização, confirmando-se em apenas 28,57% e 14,28%, respectivamente. [...] (AU)
As an important human food source, milk and its derivatives may represent a risk to public health. Although brazilian law does not permit the marketing of products without pasteurization, many producers alternatively manufacture cheese and other products from raw milk. To improve the quality and presentation of dairy products marketed by small farmers in the Toledo-PR, a project was implemented financial subsidy for the purchase of pasteurization. Aiming to evaluate the microbiological quality of dairy products produced by craftsmen in the city, samples were collected from seven cheese producers and seven of cream before pasteurization and after pasteurization of milk on the farm. Analysis of total coliforms, fecal, E. coli and Salmonella sp. Products were developed and analyzed in accordance with applicable legislation. For the results, the presence of total coliforms, all samples showed high score for this parameter before and after pasteurization, this count was not considered significant or null. Regarding the presence of fecal coliforms, seven producers (100%) of cheese producers and six (85.71%) of cream samples with results presented above that allowed by law before pasteurization, after pasteurization, while four (57,14%) and two cheese producers (28.57%) cream was found outside the required standards. We detected the presence of E. coli in samples from five producers (71.42%)of cheese and four (57.14%) of cream before pasteurization and after pasteurization, it was confirmed in 28.57% and 14.28% respectively. As the presence of Salmonella sp. Was detected the presence of this organism in samples from four producers (57.14%) and also four cheese cream in the product before pasteurization and after pasteurization was not detected the presence of this microorganism in the samples collected, confirming the efficiency of pasteurization. (AU)