Survival of Listeria Strains and Shelf Life Determination of Fresh Blueberries (Vaccinium corymbosum) Treated with Cold Atmospheric Plasma.

Fresh blueberries are delicate, hand-picked, packaged, and refrigerated fruits vulnerable to spoilage and contamination. Cold atmospheric plasma (CAP) is a promising antimicrobial technology; therefore, this study evaluated the CAP treatment effect on acid-tolerant Listeria innocua and Listeria monocytogenes and evaluated changes in the quality of the treated fruit. Samples were spot-inoculated with pH 5.5 and 6.0 acid-adapted Listeria species. Samples were treated with gliding arc CAP for 15, 30, 45, and 60 s and evaluated after 0, 1, 4, 7, and 11 days of storage at 4 °C and 90% humidity for the following quality parameters: total aerobic counts, yeast and molds, texture, color, soluble solids, pH, and titratable acidity. CAP treatments of 30 s and over demonstrated significant reductions in pathogens under both the resistant strain and pH conditions. Sixty-second CAP achieved a 0.54 Log CFU g-1 reduction in L. monocytogenes (pH 5.5) and 0.28 Log CFU g-1 for L. monocytogenes (pH 6.0). Yeast and mold counts on day 0 showed statistically significant reductions after 30, 45, and 60 s CAP with an average 2.34 Log CFU g-1 reduction when compared to non-CAP treated samples. Quality parameters did not show major significant differences among CAP treatments during shelf life. CAP is an effective antimicrobial treatment that does not significantly affect fruit quality.

Aplicação de líquidos ativados com plasma frio na endodontia / Application of plasma-activated liquids in endodontics

O insucesso do tratamento endodôntico é decorrente principalmente da presença de microrganismos remanescentes no canal radicular decorrente da dificuldade de remoção de biofilmes e das limitações dos irrigantes convencionais. Por este motivo, há necessidade de novas alternativas para a desinfecção intracanal. O objetivo deste estudo foi avaliar a atividade inibitória de líquidos ativados por plasma frio sobre biofilmes de interesse endodôntico, além de caracterizar as condições para obtenção do líquido ativado e analisar a citotoxicidade dos líquidos. Biofilmes mono e dual espécies de 24 horas foram obtidos a partir de suspensões padronizadas de Candida albicans (ATCC 18804) e Enterococcus faecalis (ATCC 29212). Os biofilmes foram expostos aos líquidos ativados, sendo estes água destilada, solução fisiológica e água mineral. Foram incluídos grupos de líquidos não ativados (controles negativos) e grupo controle de crescimento. Após 24 horas, os biofilmes foram expostos ao tratamento por 2 períodos, 1 minuto e 1,5 minutos. O número de células remanescentes foi determinado após semeadura da suspensão microbiana resultante em meios de cultura seletivos. A citotoxicidade dos líquidos ativados frente às células 3T3 foi avaliada. O teste ex vivo foi realizado em canais radiculares de dentes humanos, no qual totalizou 54 dentes humanos unirradiculares que foram preparados, instrumentados e esterilizados para receberem tratamentos com água destilada ativada. Os dados foram analisados pelo software GraphPad Prism, versão 6.01. As comparações foram feitas utilizando testes de análise de variância (ANOVA One-way), seguidas do post-hoc de Tukey, adotando-se o nível de significância de 5%. A exposição dos líquidos ativados por plasma frio levou a reduções significativas (p<0.0001) em todos os grupos quando comparados ao grupo controle de crescimento e com os grupos dos líquidos não ativados, tanto para biofilmes mono e dual espécies. A Água destilada ativada levou à maior redução em relação aos demais líquidos e o tempo de tratamento mais efetivo foi de 1,5 minutos. Os líquidos ativados não foram citotóxicos para células 3T3. No teste ex vivo, a água destilada ativada levou à redução da viabilidade dos biofilmes em 80% a 91%. Conclui-se os líquidos ativadas com plasma frio apresentaram ação inibitória sobre biofilmes mono e dual espécies formados por C. albicans e E. faecalis, tanto em modelo in vitro quanto ex vivo, com ausência de toxicidade para células 3T3.(AU)

The failure of endodontic treatment is mainly due to the presence of remaining microorganisms in the root canal due to the difficulty in removing biofilms and the limitations of conventional irrigants. For this reason, there is a need for new alternatives for intracanal disinfection. The objective of this study was to evaluate the inhibitory effect of by cold plasma activated liquids on biofilms of endodontic interest, in addition to characterizing the conditions for obtaining the activated liquid and analyzing the cytotoxicity of the liquids. 24-hours mono- and dual-species biofilms were obtained from standardized suspensions of Candida albicans (ATCC 18804) and Enterococcus faecalis (ATCC 29212). The biofilms were exposed to the activated liquids, which were distilled water, saline solution and mineral water. Non-activated liquid groups (negative controls) and growth control group were included. After 24 hours, the biofilms were exposed to treatment for 2 periods, 1 minute and 1.5 minutes. The number of remaining cells was determined by plating method using selective culture media. The cytotoxicity of activated liquids on 3T3 cells was evaluated. The ex vivo assays were carried out in root canals of human teeth. A total of 54 single-rooted human teeth were prepared, instrumented and sterilized to receive treatments with activated distilled water. Data were analyzed using GraphPad Prism software, version 6.01. Comparisons were made using analysis of variance tests (One-way ANOVA), followed by Tukey's posthoc test, adopting a significance level of 5%. Significant reduction of cell viabilities (p<0.0001) in all groups were observed after exposure to plasma activated liquids when compared to the growth control group and the non-activated liquid groups, both for mono and dual species biofilms. Activated distilled water led to the greatest reduction compared to other liquids and the most effective treatment time was 1.5 minutes. The activated liquids were not cytotoxic to 3T3 cells. In the ex vivo assay, activated distilled water led to a reduction in biofilm viability from 80% to 91%. It is concluded that plasma activated liquids showed inhibitory action on mono and dual species biofilms formed by C. albicans and E. faecalis, both in in vitro and ex vivo models, with no toxicity for 3T3 cells (AU)

Helium Cold Atmospheric Plasma Causes Morphological and Biochemical Alterations in Candida albicans Cells.

(1) Background: Previous studies reported the promising inhibitory effect of cold atmospheric plasma (CAP) on Candida albicans. However, the exact mechanisms of CAP's action on the fungal cell are still poorly understood. This study aims to elucidate the CAP effect on C. albicans cell wall, by evaluating the alterations on its structure and biochemical composition; (2) Methods: C. albicans cells treated with Helium-CAP were analyzed by atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR) in order to detect morphological, topographic and biochemical changes in the fungal cell wall. Cells treated with caspofungin were also analyzed for comparative purposes; (3) Results: Expressive morphological and topographic changes, such as increased roughness and shape modification, were observed in the cells after CAP exposure. The alterations detected were similar to those observed after the treatment with caspofungin. The main biochemical changes occurred in polysaccharides content, and an overall decrease in glucans and an increase in chitin synthesis were detected; (4) Conclusions: Helium-CAP caused morphological and topographic alterations in C. albicans cells and affected the cell wall polysaccharide content.

Effects of cold atmospheric plasma on squid proteases and gel properties of protein concentrate from squid (Argentinus ilex) mantle.

The effect of cold atmospheric plasma (CAP) on protein concentrate from squid (Argentinus ilex) mantle has been evaluated in terms of gel properties, protease inhibition, texture profile, color attributes, and water holding capacity. Different exposure time (15, 60, 120, 180, 240 and 300 s) at 60 kV have been employed. Our results indicated that protease activity decreases with increasing treatment time. The highest reduction (p < 0.05) in protease activity (64%) was observed after 240 s of CAP treatment. Texture profile analysis, color properties and water holding capacity of the treated squid gel revealed a significant increase. Protein carbonyl and sulfhydryl group contents findings' showed a significant increase in carbonyl content (about three times of the original content), while the total sulfhydryl group decreased (up to about 40%) in the crude extract. Microstructure and SDS-PAGE analysis revealed a high degree of protein aggregation in the squid gel treated with CAP.