Avaliação microbiológica de queijos tipo Minas Frescal comercializados na região do Triângulo Mineiro

No presente trabalho foram analisadas 111 amostras de queijos Minas Frescal. As análises compreenderam a determinação do Número Mais Provável de coliformes a 35ºC e a 45ºC e pesquisa de E. coli. Os resultados mostraram a presença de coliformes a 45ºC acima dos valores permitidos pela legislação em 30% dos queijos com SIF, 70% dos queijos sem SIF e 61,4% dos queijos temperados. Das Enterobacteriaceae isolados nos queijos Minas Frescal verificou-se presença de E. coli, Proteus, Providencia, Serratia, Klebsiella e Enterobacter. Foram isoladas e identificadas 1.243 E. coli e dessas amostras foram separadas aleatoriamente 330 estirpes, para pesquisar a presença do gene stx1, stx2 e eae, a detecção dos genes codificadores de adesinas (pap, afa e sfa) pela reação em cadeia da polimerase e o teste de sensibilidade aos antimicrobianos. Nenhuma estirpe testada identificou presença de stx e eae não havendo E. coli produtoras de toxina e uma estirpe apresentou o gene afa. Para o teste de sensibilidade as E. coli de todos os queijos testados apresentaram índices de resistência à tetraciclina. Neste trabalho, avaliou-se o efeito inibitório do Origanum vulgare e da Petroselinum sativum testando-os sobre coliformes a 35ºC e a 45ºC do queijo produzido com leite cru e dos queijos produzidos com leite cru acrescidos de E. coli (ATCC 25922). Os resultados dessas plantas no leite cru não promoveram efeito inibitório sobre os coliformes a 35ºC, no entanto, promoveram um efeito inibitório significativo nos coliformes a 45ºC. No leite inoculado com E. coli, os resultados apresentaram efeito inibitório para os coliformes a 35ºC e a 45ºCIn the present study, 111 samples of cheese of Fresh “Minas” type were analyzed. The analysis include the determination of the most likely number of coliforms at 35ºC and at 45ºC and research of E. coli. The results showed the presence of coliforms at 45ºC above the values allowed by the legislation in 30% of the cheese with SIF, 70% of the cheese without SIF and 61.4% of the seasoned cheese. Out of the Enterobacteriaceae isolated in the cheese of Fresh “Minas” type and the E. coli, Proteus, Providencia, Serratia, Klebsiella e Enterobacter presence was determinated. 1,234 E. coli were isolated and identified and 330 stocks were randomly separated out of these samples to research the presence of the stx1, stx2 and eae gene, the detection of the adhesine codifier genes (pap, afa and sfa), through the chain reaction of polymerase and the sensibility test to antimicrobials. No tested stock identified the presence of stx and eae, no E. coli toxin productors and a stock showed the afa gene. For the sensibility test, the E. coli of all the tested cheese showed endurance index to tetracycline. In this study, it was evaluated the inhibitory effect of the Origanum vulgare and the Petroselinum sativum by testing them on the coliforms at 35ºC and at 45ºC of the cheesed produced with raw milk and the ones produced with raw milk and E. coli (ATCC 25922). The results of these plants in the raw milk did not provoke inhibitory effect on the coliforms at 35ºC, however, they provoked a significant inhibitory effect in the coliforms at 45ºC. In the milk inoculated with E. coli, the results showed inhibitory effect for the coliforms at 35ºC and at 45º

Edible active coatings incorporated with Cinnamomum cassia and Myristica fragrans essential oils to improve shelf-life of minimally processed apples

ABSTRACT: The effect of the incorporation of cinnamon (Cinnamomum cassia) and nut meg (Myristicafragrans) essential oils in alginate-based edible coatings that were applied on minimally processed apples, is reported. The minimum inhibitory concentrations were 1.25mg.mL-1 (cinnamon) and 2.50mg.mL-1 (nutmeg), against both Escherichia coli and Penicillium commune. Over storage periods there was a significant reduction in the E. coli and P. commune counts compared to the control. The extent of enzymatic browning was also significantly reduced in the coated samples. In the coated minimally processed apples sensory tests, the flavor had the lowest rating of the properties analyzed, for both treatments, followed by aroma and firmness

ANÁLISE DE INCERTEZA E MODELAGEM DE QUALIDADE DA ÁGUA DO RIO UBERABA, MINAS GERAIS

O objetivo deste estudo foi avaliar o perfil de oxigênio dissolvido (OD) em um trecho urbano da bacia do Rio Uberaba, identificar as principais fontes poluidoras e sugerir medidas de controle. Para tanto, o estudo foi dividido em cinco fases: (i) avaliação da qualidade da água durante um ano hidrológico; (ii) calibração e validação do modelo de qualidade da água; (iii) análise de sensibilidade dos coeficientes e dos dados de entrada do modelo; (iv) análise de incerteza; e (v) criação de cenários para a tomada de decisão. Os resultados mostraram que o Córrego das Lajes é a principal fonte poluidora do Rio Uberaba. O modelo mostrou‑se confiável, uma vez que ele pôde ser calibrado e validado. Com a análise de incerteza foi possível mostrar que a probabilidade de o Rio Uberaba atender ao padrão ambiental exigido para a classe 2 (OD≥5,0 mg.L‑1) é praticamente nula, mas que ela poderia ser elevada para 75,3% se a carga orgânica lançada no rio fosse removida com uma eficiência de 75%

Shelf life and sensory analysis comparison of alginate and chitosan edible coating incorporating avocado extract applied to minimally processed apples

The purpose of the present study was to evaluate Persea americana (avocado) in relation to the pulp composition, moisture content, lipids present, proteins, and ash. The P. americana pulp extract was prepared by solvent extraction using pure ethanol, and the chemical composition of the extract was evaluated by GC-MS. The resulting extract was subsequently incorporated in alginate and chitosan-based edible coatings on minimally processed Fuji apples. The edible coatings were evaluated microscopically, for shelf-life improvement and by sensory analysis. The alginate-based coatings were able to inhibit enzymatic browning, improve the appearance of the minimally processed apple samples and obtained the best results in all aspects evaluated in the sensory analysis. The incorporation of P. americana pulp extract contributed to the improvement the shelf life of minimally processed apples for 15 days and the fruits covered with the alginate-based edible coating incorporated with P. americana pulp extract had the best scores in acceptance and appearance

Antimicrobial wound dressing films containing essential oils and oleoresins of pepper encapsulated in sodium alginate films

<div><p>ABSTRACT: Medicated wound dressings are important barriers to avoid contamination and, when they contain antimicrobial additives, can be used as treatment for infected wounds. There are several types of polysaccharide materials that serve as matrices for medicated wound dressings, among them, sodium alginate. For the preparation of the films studied in this paper, sodium alginate was employed in combination with essential oils/oleoresins (EO/OL) of six peppers that are commonly used in cooking. The EO/OL were incorporated at three different concentrations (low, intermediate and high). Most of the films prepared had better dispersion of the EO/OL at the intermediate concentration. All films studied in this research were dissolved in water at different rates. The antibacterial activity of the prepared films showed significant results against Escherichia coli, Staphylococcus aureus and Bacillus cereus, and demonstrated that the films studied may be a new alternative for medicated wound dressings.</p></div

Antimicrobial activity and chemical constituents of essential oils and oleoresins extracted from eight pepper species

ABSTRACT: Essential oils are the most important compounds produced during secondary metabolism in aromatic plants. Essential oils are volatile, have characteristic odor and are used as defensive agents by plants. In pepper, it is possible to say that essential oils are the “flavor fingerprint” of each species. In the present article, eight species of pepper were studied in order to extract their essential oils and oleoresins, test their antibacterial and antifungal activities and also to identify the compounds present in the most bioactive samples. Results demonstrated that two essential oils [Pimenta dioica (L.) Merr. and Schinus terebinthifolius] and three oleoresins (Schinus terebinthifolius and Piper nigrum white and black) recorded significant antimicrobial activity. These active essential oils and oleoresins are interesting for use in biotechnological processes employed in food, pharmaceutical and other industries