ABSTRACT The objective of the study was to determine the antimicrobial activity antibiofilm and to identify the main components of the essential oil (EO) obtained from the leaves of Cymbopogon flexuosus. The antibacterial and antibiofilm activity was determined against Staphylococcus aureus ATCC 29213, Pseudomonas aeruginosa ATCC 27853, Salmonella Typhimurium ATCC 14028 and Listeria monocytogenes ATCC 19117. The effect of EO on biofilm was evaluated by quantifying viable cell number (CFU) and biomass by crystal violet (CV) analysis. The composition of the essential oils was determined by GC / FID and GC / MS. The results showed action against L. monocytogenes, S. aureus and S. Typhimurium with MIC and MBC values of 3.9 μL mL-1, thus showing satisfactory antimicrobial activity, given this was the lowest concentration tested. For the antibiofilm activity, a significant reduction (P < 0.05) was observed for S. typhimurium and S. aureus. Biofilm biomass significantly reduced only for S. aureus and P. aeruginosa. EO presented the geranial and neral isomers as major components.

RESUMO: Os biofilmes são responsáveis pela maior parte da interferência causada pelos micro-organismos no processamento de alimentos. O objetivo deste estudo foi avaliar a atividade anti-biofilme do óleo essencial de canela (Cinnamomum zeylanicum) e do composto majoritário eugenol. As concentrações utilizadas de óleo essencial foram de 0,0% (controle), 0,12%; 0,48%; 0,96% e 1,92%; a concentração de eugenol foi de 0,76%. As concentrações foram determinadas a partir de outros estudos publicados. Determinou-se o número de células viáveis e quantificou-se a biomassa bacteriana. O tratamento anti-biofilme foi eficaz na prevenção e formação de biofilmes. A concentração de 1,92% foi satisfatória, com redução de 5,91log CFUcm-2 de células viáveis em biofilme de Escherichia coli e redução de 5,17log CFU cm-2 de Staphylococcus aureus. A biomassa de ambas bactérias foi reduzida significativamente (P<0,05), entretanto, o tratamento sanitizante não foi eficaz na redução da biomassa. Diante dos resultados, o óleo essencial de canela e eugenol podem ser alternativas promissoras no controle de biofilmes.

ABSTRACT: Biofilms are responsible for most of the interference caused by microorganisms in food processing. The aim of this study was to evaluate the cinnamon (Cinnamomum zeylanicum) essential oil and eugenol sanitizer and anti-biofilm activity against biofilms. Concentrations used of essential oil were 0.0% (control) 0.12%; 0.48%; 0.96% and 1.92%; the amount of eugenol was 0.76%. Concentrations were determined from other published studies. Number of viable cells and quantification the bacterial biomass were determined. Anti-biofilm treatment was effective in preventing the formation of biofilms. The 1.92% concentration was the most satisfactorily with Escherichia coli reduction of 5.91log CFUcm-2 and Staphylococcus aureus reduction of 5.17log CFUcm-2 (P<0.05) biomass of the two bacteria. Sanitizing treatment was not effective in reducing biomass. Seen this, the cinnamon and eugenol essential oil may be promising alternatives for controlling biofilms.

Abstract Ricotta cheese has low fat and salt contents and a high quantity of proteins. The diversity of the nutrients and the high water content are factors that favor the development of microorganisms in this product. In this context, the aim of this study was to evaluate the microbiological quality of ricotta commercialized in the western region of Santa Catarina State, Brazil. Thirty samples, comprising 10 different brands of ricotta, were collected and sent to the Food Microbiology Laboratory at the Instituto Federal Catarinense (IFC), Campus Concórdia for microbiological analysis to determine the presence of Salmonella sp., Listeria sp., coagulase-positive Staphylococcus and thermotolerant coliforms. Of the 30 samples, the results for 33.3% were not within the parameters established by current legislation, that is, they were not fit for human consumption. This high percentage was due to contamination by thermotolerant coliforms, with 10 samples containing this group of microorganisms. One sample was contaminated with Listeria grayi, and for the other microorganisms investigated, (Salmonella sp. and coagulase-positive Staphylococcus) the results were satisfactory. This study characterizes the hygiene-sanitary conditions of ricotta commercialized in the western region of Santa Catarina State, highlighting the need for greater care during the production of this product.

Resumo: O objetivo deste trabalho foi avaliar o efeito da calagem e da adubação fosfatada no crescimento, na composição mineral das folhas, na produção de frutos e na colonização micorrízica de plantas jovens de goiabeira serrana (Acca sellowiana). Os tratamentos consistiram de quatro níveis de calagem - 0, 25, 50 e 100% da dose necessária para elevar o pH do solo a 6,5 - e de cinco níveis de fósforo - 0, 60, 120, 180 e 240 kg ha-1 de P2O5 -, dispostos em delineamento de blocos ao acaso, em arranjo de parcelas subdivididas, com três repetições. O pomar foi implantado em 2010 com a cultivar Helena. Em 2012, 2013 e 2014, o crescimento das plantas foi avaliado por meio da medição do perímetro do tronco, da altura das plantas e do diâmetro das copas. A composição mineral das folhas, quanto aos teores de P, N, K, Ca e Mg, foi avaliada anualmente. A colonização micorrízica foi avaliada em 2012, e a produção de frutos foi determinada em 2014. Não houve interação entre os fatores estudados. Os níveis de P não tiveram efeito sobre as variáveis avaliadas. A calagem, no entanto, aumenta o crescimento das plantas, a colonização micorrízica, a produção de frutos e os teores foliares de Ca e Mg, além de ter reduzido o teor foliar de K.

Abstract: The objective of this work was to investigate the effect of liming and phosphorus fertilization on the growth, mineral composition of the leaves, fruit yield, and mycorrhizal colonization of young feijoa (Acca sellowiana) plants. Treatments consisted of four liming levels - 0, 25, 50, and 100% of the dose required to raise the soil pH to 6.5 - and of five levels of P - 0, 60, 120, 180, and 240 kg ha-1 P2O5 -, placed in a randomized complete block design, in a split-plot arrangement, with three replicates. The orchard was established in 2010 with the Helena cultivar. In 2012, 2013, and 2014, plant growth was evaluated by measuring trunk perimeter, plant height, and tree canopy width. Mineral composition of the leaves, regarding P, N, K, Ca, and Mg contents, was assessed annually. Mycorrhizal colonization was evaluated in 2012, and fruit yield was determined in 2014. No interaction was observed between the studied factors. P contents had no effect on the evaluated variables. Liming, however, increases plant growth, mycorrhizal colonization, fruit yield, and Ca and Mg leaf contents, besides reducing K leaf contents.