Use of antimicrobial biodegradable packaging to control Listeria monocytogenes during storage of cooked ham

The antimicrobial effect against L. monocytogenes of biodegradable films (alginate, zein and polyvinyl alcohol) containing enterocins was investigated. Survival of the pathogen was studied by means of challenge tests performed at 6 °C during 8 and 29 days, for air-packed and vacuum-packed sliced cooked ham, respectively. Air packaging was tested with two concentrations of enterocins (200 and 2000 AU/cm2). Control air-packed cooked ham showed an increase of L. monocytogenes from 104 to 107 CFU/g after 8 days. By contrast, packaging with antimicrobial films effectively slowed down the pathogen's growth, leading to final counts lower than in control lots. Air-packaging with alginate films containing 2000 AU/cm2 of enterocins effectively controlled L. monocytogenes for 8 days. An increase of only 1 log unit was observed in zein and polyvinyl alcohol lots at the same enterocin concentration. Vacuum packaging with films containing enterocins (2000 AU/cm2) also delayed the growth of the pathogen. No increase from inoculated levels was observed during 15 days in antimicrobial alginate films. After 29 days of storage, the lowest counts were obtained in samples packed with zein and alginate films containing enterocins, as well as with zein control films. The most effective treatment for controlling L. monocytogenes during 6 °C storage was vacuum-packaging of sliced cooked ham with alginate films containing 2000 AU/cm2 of enterocins. From the results obtained it can concluded that antimicrobial packaging can improve the safety of sliced cooked ham by delaying and reducing the growth of L. monocytogenes.

Assessment of high hydrostatic pressure and starter culture on the quality properties of low-acid fermented sausages

The addition of starter culture and high pressure processing after ripening improved the microbial quality of low-acid fermented sausages (fuet and chorizo). The use of Lactobacillus sakei CTC6626 and Staphylococcus xylosus CTC6013 as starter culture significantly reduced Enterobacteriaceae and Enterococcus levels in the finished sausages. Moreover, the addition of starter culture produced sausages of similar quality to traditional low-acid fermented sausages. Slightly lower pH values and higher cohesiveness were obtained for both fuet and chorizo with starter culture. Sensory analysis showed no differences between lots of chorizo whereas starter fuet was more acid and gummy. High pressure induced an additional reduction of Enterobacteriaceae in non-starter sausages. An increase of textural properties was observed after pressurization. No other differences were observed between non-treated and pressurized sausages.

High-pressure processing and antimicrobial biodegradable packaging to control Listeria monocytogenes during storage of cooked ham

The efficiency of combining high-pressure processing (HPP) and active packaging technologies to control Listeria monocytogenes growth during the shelf life of artificially inoculated cooked ham was assessed. Three lots of cooked ham were prepared: control, packaging with alginate films, and packaging with antimicrobial alginate films containing enterocins. After packaging, half of the samples were pressurized. Sliced cooked ham stored at 6 °C experienced a quick growth of L. monocytogenes. Both antimicrobial packaging and pressurization delayed the growth of the pathogen. However, at 6 °C the combination of antimicrobial packaging and HPP was necessary to achieve a reduction of inoculated levels without recovery during 60 days of storage. Further storage at 6 °C of pressurized antimicrobial packed cooked ham resulted in L. monocytogenes levels below the detection limit (day 90). On the other hand, storage at 1 °C controlled the growth of the pathogen until day 39 in non-pressurized ham, while antimicrobial packaging and storage at 1 °C exerted a bacteriostatic effect for 60 days. All HPP lots stored at 1 °C led to counts <100 CFU/g at day 60. Similar results were observed when combining both technologies. After a cold chain break no growth of L. monocytogenes was observed in pressurized ham packed with antimicrobial films, showing the efficiency of combining both technologies.

Combined effect of natural antimicrobials and high pressure processing to prevent Listeria monocytogenes growth after a cold chain break during storage of cooked ham

The effect of high pressure processing (400 MPa for 10 min) and natural antimicrobials 2 (enterocins and lactate-diacetate) on the behaviour of L. monocytogenes in sliced cooked ham 3 during refrigerated storage (1ºC and 6ºC) was assessed. The efficiency of the treatments after a 4 cold chain break was evaluated. Lactate-diacetate exerted a bacteriostatic effect against L. 5 monocytogenes during the whole storage period (3 months) at 1ºC and 6ºC, even after 6 temperature abuse. The combination of low storage temperature (1ºC), high pressure 7 processing (HPP) and addition of lactate-diacetate reduced the levels of L. monocytogenes 8 during storage by 2.7 log CFU/g. The most effective treatment was the combination of HPP, 9 enterocins and refrigeration at 1ºC, which reduced the population of the pathogen to final counts 10 of 4 MPN/g after 3 months of storage, even after the cold chain break.

Active packaging containing nisin and high pressure processing as post-processing listericidal treatments for convenience fermented sausages

Listeria monocytogenes was inoculated on the surface of sliced fermented sausages with no added sodium salt. The pathogen was progressively inactivated during the product shelf life (90 days). Antimicrobial packaging of fermented sausages with PVOH films containing nisin induced a more pronounced reduction of L. monocytogenes counts during refrigerated storage. HPP alone (600 MPa, 5 min, 12 °C) had no antimicrobial effect against L. monocytogenes at the studied conditions. Combination of HPP with antimicrobial packaging did not produce any extra protection against L. monocytogenes compared to antimicrobial packaging alone. The lack of effect of HPP on L. monocytogenes was attributed to a protective effect exerted by the low water activity of the product and its lactate content. These results reflect that antimicrobial packaging with the inclusion of nisin as a natural antimicrobial could be considered as an effective method to reduce the levels of L. monocytogenes in sliced fermented sausages with no added sodium salt

Homenatge a Teresa

Biografia de Teresa Solà, esposa de l’artista Josep Aragay, que va ser mestra de l’escola de nenes de Breda fins que fou empresonada i depurada pel franquisme

Transferència científica a l'Institut de Ci��ncia i Tecnologia Ambientals : anàlisi de la vinculaci�� universitat - societat

Aquest projecte ha estat impulsat per l’Observatori de la Divulgaci�� de la Ci��ncia (ODC) de la UAB i dut a terme a l’Institut de Ci��ncia i Tecnologia Ambientals (ICTA). Està emmarcat dins el marc del nou Programa Europeu Horizon 2020 i més específicament dels conceptes establerts per la RRI. L’objectiu d’aquest projecte és analitzar la comunicaci�� científica que duu a terme l’ICTA cap a al societat i conèixer la filosofia, els incentius i la motivaci�� de l’ICTA i els seus investigadors per donar a conèixer la seva recerca a la ciutadania. L’anàlisi de la comunicaci�� de l’ICTA consta d’un anàlisi del contingut de la pàgina web del centre de recerca, una entrevista feta a la directora de l’institut i un qüestionari realitzat a 14 investigadors Les formes de comunicaci�� que més utilitzen són els articles científics en revistes dirigides a públic acadèmic. Respecte la comunicaci�� no acadèmica, s’ha pogut observar que la majoria dels investigadors, tot i la manca de facilitats realitzaven activitats per interès personal, molts cops però, no comuniquen la seva recerca, principalment perquè tenen altres tasques de docència, de recerca i gesti�� per atendre. Hi ha una minoria que es refereix a la comunicaci�� científica com un “estil essencialment vocacional”. Per tal d’impulsar i promoure una estratègia contínua i efectiva de comunicaci�� científica cal definir un pla de comunicaci�� a nivell institucional que contribueixi a millorar les capacitats divulgatives, comunicatives i educatives de l’ICTA per tal d’ajudar a les persones que hi fan recerca a apropar la seva tasca a la societat a la que pertanyen.

Physical performance of biodegradable films intended for antimicrobial food packaging

Antimicrobial films were prepared by including enterocins to alginate, polyvinyl alcohol (PVOH), and zein films. The physical performance of the films was assessed by measuring color, microstructure (SEM), water vapor permeability (WVP), and tensile properties. All studied biopolymers showed poor WVP and limited tensile properties. PVOH showed the best performance exhibiting the lowest WVP values, higher tensile properties, and flexibility among studied biopolymers. SEM of antimicrobial films showed increased presence of voids and pores as a consequence of enterocin addition. However, changes in microstructure did not disturb WVP of films. Moreover, enterocin-containing films showed slight improvement compared to control films. Addition of enterocins to PVOH films had a plasticizing effect, by reducing its tensile strength and increasing the strain at break. The presence of enterocins had an important effect on tensile properties of zein films by significantly reducing its brittleness. Addition of enterocins, thus, proved not to disturb the physical performance of studied biopolymers. Development of new antimicrobial biodegradable packaging materials may contribute to improving food safety while reducing environmental impact derived from packaging waste.

El professorat d'Educaci�� Física a l'escola multicultural. Percepcions del context i necessitats de formaci��

El present article se centra en la situaci�� del professorat d'Educaci�� Física i les seves necessitats formatives per actuar adequadament en entorns d'escola multicultural. Amb aquesta finalitat es presenta la importància de l'educaci�� física com a agent socialitzador per a l'alumnat immigrant, les diferents tendències de les investigacions específiques sobre formaci�� del professorat d'Educaci�� Física en temes d'immigraci��, i les dades obtingudes a través d'una investigaci�� específica realitzada amb una mostra de 230 centres escolars de tot Catalunya. Com a aspectes més remarcables, cal assenyalar que encara que l'educaci�� física i l'esport poden representar un espai de trobada molt valuós per a la interculturalitat, és important no deixar de banda una educaci�� orientada cap a la convivència, i que la formaci�� del professorat sigui coherent amb les necessitats reals que s'observen en i des dels centres escolars.

Interacci��, influència educativa i formes d'organitzaci�� de l'activitat conjunta.

L'objectiu d'aquest article és presentar les principals opcions te6riques i metodol6giques d'un projecte d'investigaci�� en curs en el Departament de Psicologia Evolutiva i de l'Educaci�� de la Universitat de Barcelona. El nucli d'aquesta problematica pot definir-se, en una primera aproximaci��, com I'estudi d'alguns mecanismes d'influéncia educativa que es manifesten en la interacci�� entre el professor i els alumnes o hi actuen a través seu, en el cas de I'educaci�� escolar, i la interacci�� entre I'adult i el nen, en el cas de situacions educatives no escolars.

La demanda de professionals en l'àmbit de la gesti�� i l'administraci��. Què volen les empreses?

Ajuts a la Recerca en Docència Universitària de l'Institut de Ci��ncies de l'Educacuó de la Universitat de Barcelona REDICE-ACCI��-13

La formaci��n investigadora (I) Modelos pedagógicos

[cat] Aquest text presenta una panoràmica de la formaci�� investigadora, mostrant experi��ncies educatives i models formatius que les sustenten. Aquest àmbit d'estudi és relativament recent i les aportacions són encara més aviat escasses, com apunten alguns autors (Tight 2008; Rojas-Betancur, 2009; Evans, 2012). No obstant això, hi ha signes i evidències que la formaci�� d'investigadors està sent objecte d'atenci�� des de múltiples enfocaments, donada la seva projecci�� en diferents facetes: desenvolupament professional, processos d'innovaci��, competitivitat econòmica, millora de la qualitat de les institucions d'educaci�� superior, etc.

La formaci��n investigadora (I) Modelos pedagógicos

[cat] Aquest text presenta una panoràmica de la formaci�� investigadora, mostrant experi��ncies educatives i models formatius que les sustenten. Aquest àmbit d'estudi és relativament recent i les aportacions són encara més aviat escasses, com apunten alguns autors (Tight 2008; Rojas-Betancur, 2009; Evans, 2012). No obstant això, hi ha signes i evidències que la formaci�� d'investigadors està sent objecte d'atenci�� des de múltiples enfocaments, donada la seva projecci�� en diferents facetes: desenvolupament professional, processos d'innovaci��, competitivitat econòmica, millora de la qualitat de les institucions d'educaci�� superior, etc.

Millora de la docència en dissenys i tècniques d'investigaci�� psicològica

Podeu consultar la Setena trobada de professorat de Ci��ncies de la Salut completa a: http://hdl.handle.net/2445/43352

Panorama dels llibres infantils i juvenils dels anys 2010 i 2011

L"article presenta les tendències observades en la producci�� de llibres infantils catalans dels anys 2010 i 2011. Essencialment, la situaci�� no ha canviat en relaci�� amb els darrers anys i manté, a grans trets, unes característiques similars (publicacions relacionades amb dates assenyalades, predomini de la narrativa, seguiment dels gèneres de moda), tot i que s"apunten algunes variants relacionades amb la necessitat d"ampliar mercat, com ara l"augment de col·leccions per a petits lectors, la presència de títols que aposten pel missatge educatiu, l"edici�� de llibres acompanyats de CD i de llibres pop-up concebuts i editats aquí. L"article també repassa breument les aportacions més rellevants dels autors i dels premis publicats en aquest període.