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    Jordi Rovira

    The stress response of 11 strains of Listeria monocytogenes to oxidative stress was studied. The strains included ST1, ST5, ST7, ST6, ST9, ST87, ST199 and ST321 and were isolated from diverse food processing environments (a meat factory,... more
    The stress response of 11 strains of Listeria monocytogenes to oxidative stress was studied. The strains included ST1, ST5, ST7, ST6, ST9, ST87, ST199 and ST321 and were isolated from diverse food processing environments (a meat factory, a dairy plant and a seafood company) and sample types (floor, wall, drain, boxes, food products and water machine). Isolates were exposed to two oxidizing agents: 13.8 mM cumene hydroperoxide (CHP) and 100 mM hydrogen peroxide (H2O2) at 10 °C and 37 °C. Temperature affected the oxidative stress response as cells treated at 10 °C survived better than those treated at 37 °C. H2O2 at 37 °C was the condition tested resulting in poorest L. monocytogenes survival. Strains belonging to STs of Lineage I (ST5, ST6, ST87, ST1) were more resistant to oxidative stress than those of Lineage II (ST7, ST9, ST199 and ST321), with the exception of ST7 that showed tolerance to H2O2 at 10 °C. Isolates of each ST5 and ST9 from different food industry origins showed dif...
    In meat fermented foods, Clostridium spp. growth is kept under control by the addition of nitrite. The growing request of consumers for safer products has led to consider alternative bio-based approaches, the use of protective cultures... more
    In meat fermented foods, Clostridium spp. growth is kept under control by the addition of nitrite. The growing request of consumers for safer products has led to consider alternative bio-based approaches, the use of protective cultures being one of them. This work is aimed at checking the possibility of using two Lactobacillus spp. strains as protective cultures against Clostridium spp. in pork ground meat for fermented salami preparation. Both Lactobacillus strains displayed anti-clostridia activity in vitro using the spot agar test and after co-culturing them in liquid medium with each Clostridium strain. Only one of them, however, namely L. plantarum PCS20, was capable of effectively surviving in ground meat and of performing anti-microbial activity in carnis in a challenge test where meat was inoculated with the Clostridium strain. Therefore, this work pointed out that protective cultures can be a feasible approach for nitrite reduction in fermented meat products.
    Changes in food supply chains, health and demographic situations, lifestyle and social situations, environmental conditions, and increased legislative requirements have led to significant efforts in the development of quality and safety... more
    Changes in food supply chains, health and demographic situations, lifestyle and social situations, environmental conditions, and increased legislative requirements have led to significant efforts in the development of quality and safety management systems in agribusiness and food industry worldwide (Ropkins and Beck, 2000; Efstratiadis, Karirti, and Arvanitoyannis, 2000; Jacxsens, et al, 2009a, Luning and Marcelis, 2009a). Nowadays, companies have implemented various quality assurance (QA) guidelines and standards, such as GMP and HACCP guidelines (like General Principles of food hygiene (Codex Alimentarius 2003), GFSI guidance document (GFSI (2007), and quality assurance standards (like ISO 9001:2008 (2008), ISO22000:2005 (2005), BRC (2008), and IFS (2007) into their company own food safety management system. The performance of such systems in practice is, however, still variable. Moreover, the continuous pressure on food safety management system (FSMS) performance and the dynamic ...
    The actual microbial status of the lamb production chain at three slaughterhouses, one processing plant, and five butcher shops selling whole or cut lamb carcasses to consumers was assessed with a previously developed microbial assessment... more
    The actual microbial status of the lamb production chain at three slaughterhouses, one processing plant, and five butcher shops selling whole or cut lamb carcasses to consumers was assessed with a previously developed microbial assessment scheme. All studied establishments had a food safety management system (FSMS) that was implemented according to legislative requirements. Microbial safety level profiles were constructed for each establishment and provided clear indications of which pathogens, hygiene indicators, or utility parameters required attention to improve the performance of the microbiological control protocols of the implemented FSMS. The highest contamination was found in the slaughterhouses in samples taken from the meat products (aerobic mesophilic plate counts [AMPs] of 3.40 to 6.63 log CFU/cm(2) and Enterobacteriaceae counts of 1.00 to 4.62 log CFU/cm(2)), contact surfaces (AMPs of 2.44 to 8.92 log CFU/cm(2)), and operators' hands and/or gloves (AMPs of 2.84 to ...
    The presence and colonization of Listeria monocytogenes were investigated in a newly established dairy processing plant during a one-year period. A total of 250 non-food contact surfaces, 163 food contact surfaces, 46 personnel and 77... more
    The presence and colonization of Listeria monocytogenes were investigated in a newly established dairy processing plant during a one-year period. A total of 250 non-food contact surfaces, 163 food contact surfaces, 46 personnel and 77 food samples were analyzed in two different buildings according to the cheese production chain. Initial steps, including salting, are performed in building I (old facility), while the final steps, including ripening, cutting and packaging, are performed in building II (new facility). Overall, 218 samples were collected from building I and 318 from building II. L. monocytogenes isolates were subtyped by PFGE and MLST, and a questionnaire about quality measures was completed. The overall prevalence of L. monocytogenes was 8.40%, and while the presence of the pathogen was observed just during the first sampling in building I, L. monocytogenes was found in building II at the third sampling event. The salting area in building I had the highest proportion of...