Browsing by Author "Correia, C.B."
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- Atividade antimicrobiana: extrato de chá verde versus ácido poliláctico com o extrato incorporadoPublication . Martins, Cristiana; Maia, Carla; Furtado, Rosália; Correia, C.B.; Vilarinho, Fernanda; Sanches Silva, A.; Ramos, Fernando; Castilho, M.C.As folhas de cha verde (Camellia sinensis (L.) Kuntze) contem, na sua constituicao quimica, uma percentagem elevada de polifenois, que sao considerados otimos agentes antioxidantes e antimicrobianos. Este trabalho teve como objetivo avaliar a atividade antimicrobiana do extrato de cha verde e do filme de acido polilactico (PLA), destinado a aplicacoes alimentares, com extrato de cha verde incorporado em diferentes concentracoes, 1% e 2%. A atividade antimicrobiana foi avaliada utilizando estirpes padrao das bacterias Gram-positivas Staphylococcus aureus, Listeria monocytogenes, Enterococcus faecalis e Bacillus cereus e das bactérias Gram-negativas Escherichia coli, Pseudomonas aeruginosa e Salmonella Thyphimurium. Placas de Agar Mueller Hinton foram inoculadas com os microrganismos em estudo. Para o extrato de cha verde, a atividade antimicrobiana foi testada pelo metodo de difusao em pocos preenchidos com o extrato. Para testar a atividade antimicrobiana dos filmes foram colocados, em contacto com a superfície de agar, os filmes PLA com extrato de cha verde (1% e 2%) (filmes ativos) e sem extrato (filme controlo). Procedeu-se de seguida a incubacao das placas em condicoes de tempo e temperatura de acordo com cada microrganismo. A atividade antimicrobiana foi estimada a partir dos halos de inibicao total de crescimento microbiano Os resultados revelaram que o extrato de cha verde apresentou atividade antibacteriana sobre as bactérias Gram positivas estudadas (Staphylococcus aureus, Listeria monocytogenes, Enterococcus faecalis e Bacillus cereus). No entanto, quando e incorporado nos filmes ativos, nas concentracoes 1% e 2%, nao apresenta capacidade antimicrobiana sobre nenhum dos microrganismos testados. A quantidade de extrato de cha verde incorporado no acido polilactico e/ou metodo utilizado na incorporacao podem justificar os resultados obtidos.
- Comparison of ISO 6579–1, VIDAS Easy SLM, and SureFast® Salmonella ONE Real-time PCR, for Salmonella Detection in Different Groups of FoodstuffsPublication . Furtado, R.; Coelho, A.; Morais, M.; Leitão, A.L.; Saraiva, M.; Correia, C.B.; Batista, R.In the European Union (EU), Salmonella was the causative agent responsible for almost one in three (30.7%) of all foodborne outbreaks reported by member states during 2018, causing 11,581 cases of illness, which represented an increase of 20.6% compared to 2017. Considering the importance of this foodborne zoonotic bacterium in food safety and human health, several strategies for the control and consequent detection of Salmonella in foodstuffs are continuously being developed. In this study, we have tested 137 food samples (78 potentially naturally contaminated, 21 artificially contaminated with high levels of Salmonella, and 38 artificially contaminated with low levels of Salmonella) in order to compare the results and performance of three Salmonella detection methods: standard conventional culture (ISO 6579–1), SureFast® Salmonella ONE real-time PCR, and VIDAS® (Vitek Immunodiagnostic Assay System) Easy SLM, an Enzyme Linked Fluorescent Assay (ELFA). Although SureFast® Salmonella ONE real-time PCR was the fastest, it showed more inconclusive results, due to PCR inhibition and false positive results. ISO and VIDAS® protocols gave identical results and proved to be more robust than SureFast® Salmonella ONE real-time PCR when testing different food matrices, despite its longer response times. SureFast® Salmonella ONE real-time PCR may be appropriate to be used when the objective is to test food matrices that are known not to interfere with PCR and expected to be negative for Salmonella. All the analytical tested methods have advantages and limitations and thus, depending on the situation, may be used as the elected method for Salmonella detection in foodstuffs in accordance with the purpose of the laboratorial analysis.
- LDPE and PLA Active Food Packaging Incorporated with Lemon by-Products Extract: Preparation, Characterization and Effectiveness to Delay Lipid Oxidation in Almonds and Beef MeatPublication . Andrade, M.A.; Barbosa, C.H.; Mariño-Cortegoso, S.; Barbosa-Pereira, L.; Sendón, R.; Buonocore, G.G.; Stanzione, M.; Coelho, A.; Correia, C.B.; Saraiva, M.; Quirós, A.R.; Vilarinho, F.; Khwaldia, K.; Silva, A.S.; Ramos, F.Low-density polyethylene-based packaging with 4% lemon extract (LDPE/4LE) and two polylactic-based (PLA) packaging materials with 4% and 6% lemon extract (PLA/PEG/4LE and PLA/6LE) were produced. O2 and water permeability tests were performed, the total and individual phenolic compounds content were measured, and the films’ antioxidant activities were determined. The films’ ability to delay lipid oxidation was tested in two model foods: almonds, packaged with LDPE/4LE, PLA/4LE and PLA/6LE for a maximum period of 60 days at 40 °C (accelerated assay); and beef meat, packaged with the PLA/6LE for a maximum period of 11 days at 4 °C. The LE improved the WVP in all of the active films by 33%, 20% and 60% for the LDPE/4LE, PLA/4LE and PLA/6LE films, respectively. At the end of 10 days, the migration of phenolic compounds through the PLA films was measured to be 142.27 and 114.9 μg/dm2 for the PLA/4LE and PLA/6LE films, respectively, and was significantly higher than phenolic compounds migration measured for the LDPE/4LE (15.97 μg/dm2). Naringenin, apigenin, ferulic acid, eriocitrin, hesperidin and 4-hydroxybenzoic acid were the main identified compounds in the PLA, but only 4-hydroxybenzoic acid, naringenin and p-coumaric acid were identified in the LDPE films. Regarding the films’ ability to delay lipid oxidation, LDPE/4LE presented the best results, showing a capacity to delay lipid oxidation in almonds for 30 days. When applied to raw beef meat, the PLA/6LE packaging was able to significantly inhibit lipid oxidation for 6 days, and successfully inhibited total microorganisms’ growth until the 8th day of storage.