Characterization of Effluents Generated During the Cleaning of Expansion Tanks Used to Store Raw Milk in Brazil / Caracterização dos Efluentes Gerados Durante a Limpeza dos Tanques de Expansão Usados para Armazenar Leite Cru no Brasil

The objective of this study was to characterize the effluents generated during the cleaning of the expansion tanks used to store raw milk in Brazil. Fifteen expansion tanks were chosen and three samples collected from each tank, as well as measuring the temperature and volume. The biological oxygen demand (BOD), chemical oxygen demand (COD), acidity, pH, alkalinity, total phosphorus, nitrogen, fats and oils, hardness, turbidity and total dissolved solids were determined. The statistical design adopted was completely at random and the Scott-Knott test was adopted to compare the means that differed significantly according to the F test. The multivariate data analysis was also carried out and studied by the principal component analysis (PCA) and the grouping analysis for similarity, as represented by a dendogram. The effluents were not treated and some of them (26.7%) were discharged into water courses. The concentrations of the organic matter indicators and the results of the physicochemical analyses of the expansion tank washing effluents showed that the majority of the variables were above the legal standards established by Brazilian legislation. Thus an adequate destiny for these effluents is required. The PCA showed that the variables with the greatest influence on the characteristics of the expansion tank effluents were related to the COD and nitrogen concentrations. A total of 88% of similarity was found between the effluents of the 15 tanks. According to the concentrations obtained for the phosphorus, nitrogen, COD and BOD of the effluents, they could be treated by the wetlands systems.The objective of this study was to characterize the effluents generated during the cleaning of the expansion tanks used to store raw milk in Brazil. Fifteen expansion tanks were chosen and three samples collected from each tank, as well as measuring the temperature and volume. The biological oxygen demand (BOD), chemical oxygen demand (COD), acidity, pH, alkalinity, total phosphorus, nitrogen, fats and oils, hardness, turbidity and total dissolved solids were determined. The statistical design adopted was completely at random and the Scott-Knott test was adopted to compare the means that differed significantly according to the F test. The multivariate data analysis was also carried out and studied by the principal component analysis (PCA) and the grouping analysis for similarity, as represented by a dendogram. The effluents were not treated and some of them (26.7%) were discharged into water courses. The concentrations of the organic matter indicators and the results of the physicochemical analyses of the expansion tank washing effluents showed that the majority of the variables were above the legal standards established by Brazilian legislation. Thus an adequate destiny for these effluents is required. The PCA showed that the variables with the greatest influence on the characteristics of the expansion tank effluents were related to the COD and nitrogen concentrations. A total of 88% of similarity was found between the effluents of the 15 tanks. According to the concentrations obtained for the phosphorus, nitrogen, COD and BOD of the effluents, they could be treated by the wetlands systems

Storage temperature and microbiological quality of bulk raw milk in Rio Pomba, Minas Gerais

The refrigeration of raw milk in bulk tanks represents an obstacle in the milk production chain associated with the selection of spoilage psychrotrophic bacteria with negative consequences for the industry. The aim of this work was to evaluate the temperature and microbiological quality of raw milk stored in 15 refrigeration tanks in the city of Rio Pomba, Minas Gerais, in the seasons, between October 2016 and July 2017. The temperature of the milk in each tank was determined at the time of sample collection. Subsequently, counts of aerobic mesophilic, psychrotrophic, pro teolytic psychrotrophic, lipolytic psychrotrophic, lecithinase-producing psychrotrophic and Pseudomonas sp. were determined. There was no difference (p > 0.05) in milk temperature at the time of collection among the 15 bulk tanks, however, the temperature averages were above 4.0 ºC, therefore in disagreement with Normative Instruction n.º 76. The aerobic mesophilic count varied between 3.4 and 6.8 Log CFU/mL, and 42% of the samples did not comply with the legal standard. The count of psychrotrophic microorganisms presented variation between 3.0 and 8.1 Log CFU/mL with mean equal (p > 0.05) to the count of aerobic mesophilic microorganisms. More than 50% of the samples presented counts of Pseudomonas sp. above 4.0 log CFU/mL. It was concluded that the hygienic-sanitary conditions in the production of raw milk in the city of Rio Pomba, MG, were inadequate, thus highlighting the importance of contamination prevention of raw milk through the implementation of Good Practices in productive chain

Ação Proteolítica de Bactérias Psicrotróficas nas Caseínas do Leite Bovino / Proteolytic Action of Psychrothrophic Bacteria in Bovine Milk Caseins

A refrigeração do leite cru propicia a multiplicação da microbiota psicrotrófica proteolítica contaminante, que é capaz de hidrolisar as caseínas, com consequentes problemas tecnológicos e econômicos para a indústria. Objetivou-se avaliar a ação proteolítica de bactérias psicrotróficas isoladas de leite cru refrigerado nas caseínas. Sete isolados Gram-negativos altamente proteolíticos foram selecionados e cada isolado, entre 6,0 e 7,0 Log UFC/mL, individualmente, foi inoculado em 100 mL de leite pasteurizado e incubado a 7,0 ºC. Realizou-se contagem padrão em placas de microrganismos mesófilos aeróbios e contagem de bactérias psicrotróficas proteolíticas viáveis, com 0, 48 e 96 horas de estocagem. A estabilidade térmica das amostras de leite foi avaliada utilizando-se o teste do álcool, com graduação de 68 ºGL a 80 ºGL (v/v) e o perfil proteolítico das caseínas avaliado por SDS-PAGE. Durante a estocagem das amostras, houve aumento da contagem de bactérias psicrotróficas, exceto na amostra inoculada com Burkholderia cepacia, que se manteve constante. Observou-se maior instabilidade térmica nas amostras inoculadas com Acinetobacter baumannii, Stenotrophomonas maltophilia, Pseudomonas luteola, Aeromonas hydrophila/caviae e B. cepacia após 48 horas e, com 96 horas, todas as amostras apresentaram-se instáveis ao etanol 80 ºGL. A técnica de SDS-PAGE evidenciou  proteólise das caseínas com 48 horas de incubação, nas amostras inoculadas com Pseudomonas fluorescens. Após 96 horas, observou-se intensa hidrólise das caseínas do leite nas amostras inoculadas com P. fluorescens, A. baumannii, S. maltophilia e B. cepacia. Menor grau de hidrólise foi observado nas amostras inoculadas com P. luteola, A. junii/johnsonii, e A. hydrophila/caviae. Conclui-se que as diferentes espécies de bactérias psicrotróficas hidrolisaram as caseínas do leite de forma mais ou menos intensa, e que quanto maior o tempo de armazenamento do mesmo sob refrigeração, maior é a presença de peptídeos provenientes da hidrólise. Portanto, a prevenção e controle da contaminação do leite são imprescindíveis para evitar a proteólise da caseína e consequentes perdas de qualidade e rendimento na produção de lácteos

Environmental impacts of dairy effluent on waterway in the Pomba River Basin

<p></p><p>ABSTRACT Dairy activity has economic and environmental importance in the Pomba River Basin. Aiming to check for possible environmental impacts of dairy effluents on watercourses, five dairy effluents were characterized during the production cycle. To select the variables important for the characterization of effluents, it was applied a principal component analysis (PCA). Data obtained were compared with official regulations and it was simulated the impact of the discharge of effluents, treated or non-treated, on a waterway. The most significant variables in the effluent analysis were conductivity, biochemical oxygen demand (BOD), total phosphorus, turbidity, temperature and pH. Dairy plants do not comply with legal standards for effluent discharge, even with treatment plants installed. The main reason is the low use of whey, associated with inefficient treatment of effluents. By simulating the discharge of effluents, it can be concluded that the reduction of BOD should be 60-70% for the river water did not exceed the standard limits for BOD. The simulation was important to determine the impacts of dairy effluents and can be applied to other dairy plants in order to ensure that effluent cause no environmental damage. Developing products or technology for the better use of whey in small dairy plants, adequately treat the effluents, and reduce water consumption are considered important actions to reduce environmental impacts on water resources.</p><p></p