Inactivation of Salmonella typhimurium by cold plasma activated water application

[SPA] El plasma frío es definido como el cuarto estado de la materia y es generado por una serie de descargas denominadas Spark y Glow, las cuales originan unas sustancias químicas que pueden interaccionar con microorganismos dando lugar a la inactivación de estos. S. typhimurium ha sido el patógeno elegido para este trabajo, ya que es el segundo serovar de Salmonella spp., con más casos de Salmonelosis en el año 2018. Los resultados aportados en este estudio mostraron un claro efecto sobre la inactivación de S. typhimurium debido a las especies reactivas generada durante los tratamientos PAW.] [ENG] Cold plasma is defined as the fourth state of matter and is generated by a series of discharges called Spark and Glow, which originate chemical substances that can interact with microorganisms resulting in the inactivation of these. S. typhimurium has been the pathogen of choice for this work, since it is the second serovar of Salmonella spp. with more cases of Salmonellosis in 2018. The results provided in this study, showed a clear effect on the inactivation of S. typhimurium due to the reactive species generated during PAW treatments.Gracias al MINECO, AEI y FEDER, por la financiación del proyecto "Validación de nuevas herramientas y procesos para el análisis y la mejora de la seguridad alimentaria microbiológica", con cargo a la partida presupuestaria: 30.05.18.80.79 541A 642.10

Algal Polysaccharides. Innovative Extraction Technologies, Health Benefits and Industrial Applications

Microalgae are largely exploited due to their rich composition in high-value compounds such as carbohydrates. Algal polysaccharides and oligosaccharides offer enormous potential industrial applications due to their wide range of biological activities. The production and chemical structure of microalgal carbohydrates will vary depending on the species or strains and the culture conditions (i.e. temperature, pH and light). Moreover, microalgae are able to accumulate and/or excrete intra- and extra-cellular carbohydrates. Due to the wide heterogeneity of these compounds, the extraction and purification processes are challenging stages in the downstream processing of microalgal polysaccharides. This chapter focuses on the extraction and purification approaches to obtain carbohydrates from microalgae together with the biological activities and potential industrial applications of these compounds.Ministerio de economía, industria y competitividad (MINECO)Agencia estatal de investigación (AEI)Fondo Europeo de Desarrollo Regional (FEDER

The Different Response to an Acid Shock of Two Salmonella Strains Marks Their Resistance to Thermal Treatments

Microbial cells respond to sub-lethal stresses with several physiological changes to increase their chance of survival. These changes are of high relevance when combined treatments (hurdle technology) are applied during food production, as the cells surviving the first hurdle may have greater resistance to subsequent treatments than untreated cells. In this study, we analyzed if Salmonella develops increased resistance to thermal treatments after the application of an acid shock. We compared the heat resistance of acid-shocked (pH 4.5 achieved with citric acid) Salmonella cells with that of cells maintained at pH 7 (control cells). Thermal treatments were performed between 57.5 and 65°C. We observed a differential response between the two strains studied. Acid-shocked cells of Salmonella Senftenberg exhibited reduced heat resistance, e.g., for a treatment at 60.0°C and pH 7.0 the time required to reduce the population by 3 log cycles was lowered from 10.75 to 1.98min with respect to control cells. Salmonella Enteritidis showed a different response, with acid-shocked cells having similar resistance than untreated cells (the time required to reduce 3 log cycles at 60.0°C and pH 7.0 was 0.30min for control and 0.31min for acid-shock cells). Based on results by differential plating (with or without adding the maximum non-inhibitory concentration of NaCl to the recovery medium), we hypothesize that the differential response between strains can be associated to sub-lethal damage to the cell membrane of S. Senftenberg caused by the acid shock. These results provide evidence that different strains of the same species can respond differently to an acid shock and highlight the relevance of cross-resistances for microbial risk assessment

Endoscopically placed stents: a useful alternative for the management of refractory benign cervical esophageal stenosis

Introduction: Benign esophageal strictures are relatively frequent and can severely affect the quality of life of a patient. Stenting has been proposed for the treatment of refractory cases. Lesions affecting the cervical esophagus are more difficult to treat, and the placement of stents in this location has traditionally been restricted due to potential adverse events. The aim of this study was to describe the efficacy and safety of endoscopic stenting in the management of refractory benign cervical esophageal strictures (RBCES) in a single-center cohort study. Methods: We analyzed 12 patients with RBCES (Kochman's criteria) and severe dysphagia. We recorded previous endoscopic treatments, stricture characteristics and demographic data. The two types of stents used were fully covered self-expandable metallic stents (FCSEMS) and uncovered biodegradable stents (BDS). FCSEMS were removed eight weeks after placement, and BDS were followed-up until degradation. We assessed technical and clinical success, rate of stricture recurrence and adverse events. Results: The mean age of participants was 64 years (range 30-85). A total of 23 stents (13 FCSEMS and 10 BDS) were placed in 12 patients (median 1.92, range 1-4). The technical success rate was 96% (22/23 stents). Eight patients (66.6%) maintained adequate oral intake at the end of follow-up (median 33.3 months, range 3-84 months). Migration was recorded in 7/23 stents (30.4%) and epithelial hyperplasia in 4/23 stents (17.4%). No severe adverse events were noted. All patients complained of minor cervical pain after placement that was well controlled with mild analgesia. Conclusions: Endoscopic stent therapy seems to be effective and safe in the management of RBCES