Bioaerossóis em ambientes hospitalares

Bioaerossol se refere aos aerossóis biológicos dispersos na atmosfera formados de partículas bióticas ou abióticas de ecossistemas terrestres e marinhos. A composição da microbiota dos bioaerossóis é variável, dinâmica e relativa às origens de seus componentes, bem como à temperatura e à umidade do meio no qual estão suspensas. Este artigo revisa sistematicamente a literatura relacionada ao potencial epidemiológico dispersivo de bioaerossóis no ambiente hospitalar. Os bioaerossóis, assim como as gotículas, constituem importantes meios de transmissão de patógenos e o impacto dessas partículas em ambientes hospitalares é de importância, por estarem associadas à diversas doenças nosocomiais. O novo coronavírus possui alto poder de contágio e utiliza a rota aérea como uma das vias para transmissão, o que evidencia a importância de garantia da qualidade do ar em ambientes hospitalares no momento em que uma pandemia mundial está em curso.

Growth and antibacterial activity of Lentinula edodes in liquid media supplemented with agricultural wastes

Antibacterial activity of Lentinula edodes against Bacillus subtilis was evaluated in cell-free filtrates obtained after growth in 14 different culture media. The highest B. subtilis growth inhibition was promoted by filtrates of growth media supplemented with rice bran, vermiculite or molasses. L. edodes dry mycelial biomass in liquid culture with 0.5% added rice bran was 3.2 mg/ml, after growth for 30 days at 25\ub0C without shaking, and 4.3 mg/ml under orbital shaking (150 rpm). However, antibacterial activity, detected between 20 and 24 days of incubation of stationary cultures, was absent in filtrates of aerated cultures. Temperatures of 20-25\ub0C enhanced both growth and antibacterial activity. Optimum pH for L. edodes mycelial growth was 3.0-3.5, while for production of antibacterial substance(s) it was 4.5. Our results indicated that incubation conditions that enhance mycelial growth are quite different from those necessary for production of antibacterial substance(s) by L. edodes

Proteolytic potential of pseudomonas fluorescens isolated from refrigerated raw milk

The growth rate and the proteolytic activity of Pseudomonas fluorescens strains 07A and 041, isolated from cow’s milk, were evaluated at 2, 4, 7 and 10ºC. P. fluorescens promoted protein degradation during storage of milk samples as observed by Proteolytic activity measurement, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and heat stability of milk. Casein hydrolysis resulted in loss of thermal stability of milk and in formation of fragments of low and medium molecular mass. Temperatures up to 10°C did notA taxa de crescimento e a atividade proteolítica das estirpes 07A e 041 de Pseudomonas fluorescens, isoladas a partir de leite cru de vacas, foram avaliadas após incubação a 2, 4, 7 e 10°C. P. fluorescens promoveu a degradação de proteínas durante armazenamento de amostras de leite, como observado pela determinação da atividade proteolítica, por eletroforese em gel de poliacrilamida desnaturante (SDS-PAGE) e pela estabilidade térmica do leite. A hidrólise da caseína resultou na perda da estabilidade térmica do leite e na formação de fragmentos de baixa e média massa molecular. Temperaturas de até 10°C não garantiram a qualidade do leite cru quando a contaminação por P. fluorescens foi igual ou superior a 10 6 UFC/mL

Enrichment of mushrooms: an interesting strategy for the acquisition of lithium

The capability of Pleurotus ostreatus mushroom to accumulate lithium (Li) and the accessibility of this Li compared with lithium carbonate (Li2CO3), often used as psychiatric medicine, were investigated. Mushrooms were produced on a substrate-based on coffee husk, with different added concentrations of lithium chloride (LiCl). Biological efficiency (BE), the crude protein content, the concentration of Li and other elements present in mushrooms were determined. The sequential extraction and in vitro test were used to verify the accessibility and the degree of solubility of this element. Li concentration in mushrooms was directly influenced by increasing LiCl concentration in the substrate (P < 0.05). The BE was not affected by different concentrations of LiCl. Li present in enriched mushrooms showed greater accessibility than in Li2CO3. Therefore, P. ostreatus mushrooms, enriched with lithium can be an alternative source of Li, as well as being a food with high nutritional value

THERMOSTABILITY OF XYLANOLYTIC ENZYMES PRODUCED BY LENTINULA EDODES UFV70

Xylanolytic enzymes produced by Lentinula edodes UFV70, cultivated in eucalyptus sawdust/rice bran medium, were stable at 50, 60 and 65 degrees C for 21 hours, losing only 15-25% activity. Fungus incubation at 50 degrees C for 12 hours and at 65 degrees C for 24 hours increased the amount of xylose produced

Effect edible antimicrobial coating in the white blush and anaerobic psychrotrophs baby carrots

[POR] Objetivou-se avaliar a qualidade visual e microbiológica de minicenouras submetidas a diferentes concentrações de amido de milho em suspensão utilizado para revestimento comestível. Cenouras cv. Esplanada colhidas aos 90 dias, minimamente processadas na forma de minicenouras, foram imersas em suspensão contendo 2, 3 ou 4% de amido de milho; 1,5 % de quitosana, 2 % de glicerol e 0,4 % de ácido acético glacial e mantidas sob ventilação. Minicenouras não imersas em suspensão, serviram de controle. Em seguida, as minicenouras foram embaladas em bandejas de polipropileno envoltas em filme de polivinilcloreto e mantidas a 5±1ºC, por 12 ou 15 dias. Minicenouras sem revestimento, apresentaram intenso aumento no índice de esbranquecimento, e no quarto dia, apresentaram entre 21 a 60 % de sua superfície esbranquecida. Independente da concentração de amido na suspensão, o índice de esbranquecimento não alterou. As minicenouras tratadas em suspensão contendo 4 % de amido, não apresentaram sintomas visuais de esbranquecimento durante todo o armazenamento. As minicenouras tratadas em suspensão contendo 2 ou 3% de amido, apresentaram até 20% da superfície esbranquecida, nas extremidades, sem comprometer sua qualidade visual. O tempo para secagem do revestimento foi de proximadamente 2,5; 3,5 e 5h para minicenoura tratadas em suspensão com 2, 3 e 4 %, respectivamente, dificultando o uso de suspensão mais concentrada. A velocidade de perda de massa fresca apresentou a mesma tendência para todos os tratamentos. O revestimento utilizado contendo quitosana, inibiu em 1,2 ciclos logs o crescimento de psicotróficos anaeróbicos após 15 dias, em relação ao controle. A suspensão contendo 2 ou 3 % de amido de milho, proporcionou manutenção da coloração característica de minicenoura e inibiu parcialmente o crescimento de psicotróficos anaeróbicos. Apoio financeiro: CAPES, CNPq e FAPEMIG. [ENG] This work aimed to develop an edible antimicrobial coating base on a starch- chitosan matrix to evaluate is effect on baby carrot by means of visual quality and anaerobic Psychrotrophs analyses. Carrots of, Esplanada cultivar were harvested at 90 days after planting, were minimally processed in form of baby carrots and immersed in the suspensión coating based on 2; 3 or 4 % maiz starch (w/v) + 2 % glycerol (v/v) + chitosan (1,5 %, w/v) and 0,4 % glacial acetic acid (v/v). All the samples were placed in extended polystyrene trays, wrapped in polyvinylchloride film and stored at 5±1 ºC for 12 or 15 days. Baby carrot no immersed, presented intense increase whiteness index, and 21 – 60 % at days four whitness surface. Independent of the starch concentration in the suspension, the whiteness index did not modify. The Baby carrot treated in suspension contend 4 % of starch, had not presented visual symptoms of whiteness during the storage. The baby carrots treated in suspension contend 2 or 3% of starch, had presented up to 20 % of the whiteness surface, in the extremities, without compromising its visual quality. The time for drying of the coatings was of approximately 2,5; 3,5 and 5h for baby carrot treated in suspension with 2, 3 and 4 %, respectively, making it difficult the use of more concentred suspension. The speed of mass loss presented the same trend for all the treatments. The use chitosan in the coating, inhibited in 1,2 cycles logs the growth of anaerobic psychrotrophs after 15 days, in relation to the control. The suspensión contend 2 or 3 % of maize starch, provided maintenance of the characteristic coloration of baby carrot and inhibited partially the anaerobic psychrotrophs growth.Os autores agradecem ao prof. Ricardo Henrique Silva Santos e estudantes pelo fornecimento da matéria-prima. À CAPES, CNPq e FAPEMIG pelo apoio financeiro