Microbiological profile of raw refrigerated and processed bovine milk at dairy industries from Vale do Taquari, Rio Grande do Sul, Brazil

Milk is an essential food, widely consumed by the population. Brazil is one of the world's largest producers of milk. Milk quality is influenced by several factors in all its stages of production. The aim of this study was to determine the microbiological profile of refrigerated and processed raw bovine milk from industries in Vale do Taquari, state of Rio Grande do Sul, Brazil, using metagenomic analysis. A total of six samples were collected, one of refrigerated raw milk from the tanker truck, one of pasteurized milk and one of milk sterilized by the ultra-high temperature (UHT) process, in each of the industries. The identification of the milk microbiota was performed by sequencing the 16S rRNA gene. The results show that refrigerated raw milk has a greater number of microorganisms, followed by pasteurized milk and sterilized milk, successively. Processed milk showed the presence of beneficial microorganisms such as Streptococcus thermophilus and Streptococcus macedonicus. Nevertheless, even UHT milk showed the presence of microorganisms considered harmful, such as the Bacillus cereus group, Aeromonas dhakensis, Enterobacter bacterium and Acinetobacter haemolyticus. Metagenomics is a valuable tool for the thorough evaluation of the milk microbiota in order to implement the processing stages in industries.

Anti-Escherichia coli effect of Hibiscus sabdariffa L. in a meat model

Abstract Hibiscus sabdariffa L. is used in traditional medicine because of its bioactive properties, such as antioxidant and antibacterial. Escherichia coli is a Gram-negative bacteria and as an indicator of contamination in food. The aim of this work was to evaluate the anti-Escherichia coli effect and the change in pH on the control of aerobic mesophilic microorganisms, using hydroethanolic extract of H. sabdariffa L. in different concentrations in a meat model, verifying its potential as food additive for microbiological stability on ground beef during cooling storage. For the preparation of the treatments, the meat experimental units were elaborated with different concentrations of the vegetal extract (5, 10, 15 and 20%), ground beef and contaminated with E. coli. For pH evaluation, the meat experimental units were added different percentages of hydroethanolic extract. The H. sabdariffa L. antibacterial action reduced two logarithmic levels in practically all treatments. The best pH result was obtained in the meat containing 30% of the extract. The hydroethanolic extracts of Hibiscus sabdariffa L. showed anti-Escherichia coli activity in the presence of refrigerated ground beef. Analyzing the pH results and the count of aerobic mesophilic bacteria, it is possible this extract to be used as a natural food additive.

Avaliação do extrato alcoólico de hibisco (Hibiscus sabdariffa L. )como fator de proteção antibacteriana e antioxidante / Evaluation of the alcoholic extract of hibiscus (Hibiscus sabdariffa L. ) as a protective antibacterial and antioxidant component

O hibisco (Hibiscus sabdariffa L.) possui propriedades antioxidantes e antimicrobianas, e pode ser utilizado como planta medicinal e alimento funcional. Este estudo determinou a intensidade de atividade de inibição (IINIB) e a inativação bacteriana (IINAB) in vitro de dois extratos alcoólicos, obtidos de cálices e frutos com sementes de diferentes acessos de hibisco. As análises foram efetuadas sobre as bactérias de padrão internacional, Enterococcus faecalis, E. coli, Salmonella Enteritidis e S. aureus, associando-se os resultados aos polifenóis totais e antocianinas. Diferenças significativas na atividade antimicrobiana dos extratos alcoólicos foram observadas em ambos os acessos. Salmonella Enteritidis (11,5) e E. coli (12) foram as bactérias mais sensíveis, respectivamente, aos extratos alcoólicos de cálices de hibisco e dos frutos com sementes. S. aureus (5,2 e 0,1) foi a mais resistente a ambos os extratos. Os valores de IINIB foram predominantemente maiores quando comparados aos de IINAB, o que indica que geralmente a atividade bacteriostática é maior do que a bactericida. Os valores de polifenóis totais e de antocianinas do extrato alcoólico de cálices apresentaram diferença significativa e foram superiores aos do extrato alcoólico dos frutos com sementes. Possivelmente exista associação direta entre a concentração de antocianina e a atividade antibacteriana em diferentes estruturas vegetais do hibisco.

Avaliação das concentrações de nitrato e nitrito em hortaliças produzidas em Ccltivos convencional e orgânico na Região do Vale do Taquari ? RS / Nitrate and nitrite determination in vegetables produced in conventional and organic farming in the Region of Taquari Valley- RS

Ao longo dos últimos anos é crescente a preocupação com a qualidade de vida e a preservação da saúde. A cultura orgânica, diante da tendência ao consumo de alimentos mais saudáveis, visa produzir alimentos sem a adição de agrotóxicos ou qualquer produto químico. Esta agricultura tem-se intensificado, pois contraria a agricultura convencional, cujo objetivo principal é a utilização intensiva de terras e de tecnologias que acarreta em um grande uso de fertilizantes, inseticidas e herbicidas. As hortaliças são componentes importantes em uma dieta saudável, ajudando a diminuir o risco de determinadas doenças, além de favorecer o trânsito intestinal e proporcionar efeito antioxidante no organismo. No entanto, estas hortaliças possuem nitrato e nitrito, componentes naturais, precursores de algumas formas de câncer e da metahemoglobinemia. Portanto, este trabalho teve como objetivo comparar a concentração de nitrato e nitrito em hortaliças, como beterraba, cenoura, espinafre e repolho, cultivados de forma convencional e orgânica. A determinação de nitrato e nitrito foi baseada na metodologia oficial do Ministério da Agricultura, Pecuária e Abastecimento e os resultados foram comparados através do Statistica® for Windows versão 7.0. O nitrito foi encontrado na beterraba e no espinafre e o nitrato ocorreu em todas as amostras analisadas. Todos os vegetais apresentaram médias de valores superiores a 1000 mg/kg, portanto foram classificados como hortaliças com alto conteúdo de nitrato. Houve diferença significativa entre os níveis de nitrato dos vegetais da agricultura convencional para a orgânica, mostrando que o consumo de hortaliças orgânicas favorece uma menor ingestão destes elementos.

In recent years there is a concern about the quality of life and public health. The organic farming aims to produce organic foods without pesticides due to the trend towards consumption of healthier foods. This type of farming contradicts the conventional farming, whose main objective is the intensive use of land, technology and fertilizers, insecticides and herbicides. Vegetables are important components in a healthy diet, since they minimize some disease risks, promote intestinal function and provide antioxidant effects in the body. However, these vegetables contain nitrate and nitrite, natural compounds, precursors of some forms of cancer and methemoglobinaemia. This study aimed to compare the concentration of nitrate and nitrite in vegetables such as beets, carrots, spinach and cabbage, grown in conventional and organic production. The determination of nitrate and nitrite was based on the official methodology of the Ministry of Agriculture, Livestock and Food Supply and the results were evaluated using the Statistica® for Windows version 7.0. Nitrite was found in beets and spinach and nitrate was found in all the samples. All plants showed high content of nitrate, which exceeded 1000 mg/kg. There were significant differences between the levels of nitrate from conventional farming to organic one, which shows that the intake of organic vegetables benefits a lower intake of these elements.