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- Evaluation of antimicrobial susceptibility among Campylobacter jejuniPublication . Camilo, Rute; Mena, Cristina; Silva, Joana; Teixeira, Paula
- Characterisation of alheiras, traditional sausages produced in the North of Portugal, with respect to their microbiological safetyPublication . Ferreira, Vânia; Barbosa, Joana; Silva, Joana; Felício, Maria Teresa; Mena, Cristina; Hogg, Tim; Gibbs, Paul; Teixeira, PaulaThe objective of this study was the characterisation of alheiras, traditional Portuguese sausages, with respect to their microbiological safety. Thirty-eight lots from 17 producers were analysed. The microbiological status of the analysed product can be considered of concern in terms of food safety. Although Campylobacter spp. and Escherichia coli O157 were not detected in any sample,and Clostridium perfringens when present was not at levels of concern with reference to public health, Salmonella spp. were detected in 2 lots of industrially produced alheiras, and more than 60% of the lots analysed were contaminated with Listeria monocytogenes in concentrations higher than 100 cfu/g.
- Food Safety in the domestic environment: incidence of Listeria monocytogenes in domestic refrigeratorsPublication . Marujo, Daniela; Pereira, Isabel; Mena, Cristina; Carneiro, Luísa; Almeida, Gonçalo; Teixeira, Paula; Gibbs, Paul
- Incidence of Listeria spp. in domestic refrigerators in PortugalPublication . Azevedo, Inês; Regalo, Mafalda; Mena, Cristina; Almeida, Gonçalo; Carneiro, Luísa; Teixeira, Paula; Hogg, Tim; Gibbs, Paul A.The main objectives of this study were to determine the incidence of Listeria spp. in Portuguese domestic refrigerators and to evaluate some of the hygienic practices in the domestic environment that might contribute to the persistence of the organisms. It was found that L. monocytogenes was present in 3 domestic refrigerators of the 86 investigated. L. grayi and L. innocua were also isolated from 4 and 1 refrigerators, respectively. Overall, the information obtained from our survey demonstrates the need for consumer education in Portugal regarding safe food handling practices. For the refrigerators investigated, ≈71% were operating at a temperature higher than 6.1ºC, 87% were cleaned only monthly or less frequently, and only 8% were cleaned with appropriate proprietary cleaning products available in supermarkets.
- Comparison of Oxford Agar, PALCAM and Listeria monocytogenes Blood Agar for the recovery of L. monocytogenes from foods and environmental samplesPublication . Pinto, Marlene; Burria, Solange; Mena, Cristina; Almeida, Gonçalo; Carneiro, Luísa; Teixeira, Paula; Gibbs, Paul A.This work had as the main objective a comparison between Listeria monocytogenes Blood Agar (LMBA) and the conventional selective agar media, Oxford and PALCAM, relative to its efficacy in the detection of L. monocytogenes in naturally contaminated food and environmental samples. 173 environmental samples and 272 samples of foods were analysed. A higher sensitivity for detection of L. monocytogenes was verified for LMBA than for PALCAM and Oxford. In LMBA L. monocytogenes could be distinguished from other Listeria spp. by detection of hemolysis. In Oxford and PALCAM this distinction was not possible. The higher growth rate of L. innocua cf. L. monocytogenes in selective liquid media could result in a high number of false negatives (non-detection of the target organism on plates, although its presence was observed by other tests, eg. mini-VIDAS LMO). The need for specific media for the detection of L. monocytogenes in food was confirmed. LMBA could be an alternative medium to use together with PALCAM or Oxford.
- Use of predictive modelling software in the evaluation of corrective actions, HACCP plans, within artesanal dairy productsPublication . Campelos, I.; Mena, C.; Gibbs, P.; Hogg, T.; Teixeira, P.
- Evaluation of the hippurate test as a method for the differentiation between Campylobacter jejuni and Campylobacter coliPublication . Mena, C.; Leite, D.; Silva, J.; Gibbs, P.; Teixeira, P.
- Activity of wine against campylobacter jejuniPublication . Carneiro, Anabela; Couto, José António; Mena, Cristina; Queiroz, Jorge; Hogg, TimThis study focuses on the activity of wine against the important food-borne pathogen Campylobacter jejuni. The kinetics of inactivation of two strains of C. jejuni (one food-borne and one clinical) were characterised in various scenarios of exposure to wine and wine components. Undiluted wine was found to rapidly inactivate C. jejuni (>6D inactivation within 30 s); further inactivation data were obtained from experiments performed in wine diluted with water (1:2 and 1:4). Experiments with isolated antimicrobial fractions of wine (ethanol and certain organic acids) suggest that these two components act synergistically, demonstrating an inactivation capacity similar to wine itself. The results indicate that the exposure of contaminated food to wine, as in marinade conditions, Significantly reduces the number of viable cells of C. jejuni. A model stomach, containing a food matrix and a synthetic gastric fluid, was used to infer the effect of wine against C. jejuni in a consumption-like scenario. Wine was found to potentiate the anti-Campylobacter effect of gastric fluid. The results strongly suggest that the ingestion of wine during a meal may greatly diminish the quantity of C. jejuni persisting further in the alimentary tract, thus lowering the risk of infection
- Evaluation of the hippurate test as a method for the differentiation between Campylobacter jejuni and Campylobacter coliPublication . Mena, C.; Leite, D.; Silva, J.; Gibbs, P.; Teixeira, P.
- Occurrence, identification, and characterization of campylobacter species isolated from portuguese poultry samples collected from retail establishmentsPublication . Mena, C.; Rodrigues, D.; Silva, J.; Gibbs, P.; Teixeira, P.Campylobacter spp. are a leading cause of human diarrhea. The common source of infection is contaminated food, particularly poultry. From May 2005 to October 2006, 164 samples of poultry obtained from several retail establishments and from different Portuguese producers were analyzed for the presence of Campylobacter spp.Atotal of 99 Campylobacter strains were isolated and further identified. Susceptibilities for 44 strains were determined for 11 antimicrobial drugs by the agar diffu-sion technique. According to the minimal inhibitory concentration for 90% of the isolates, resistance to tetracycline, nalidixic acid, rifampicin, erythromycin, vancomycin and penicillin was observed. Sensitivity to gentamycin and chloramphenicol was also demonstrated. According to the antibiotic resistance profiles, the isolates appeared to differ from each other, including those that had been collected at the same period of time and from the same chicken sample.