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- Microbiological contamination of reusable plastic bags for food transportationPublication . Barbosa, J.; Albano, H.; Silva, C. P.; Teixeira, P.Nowadays, with so many concerns for the environment, the use of reusable plastic bags is becoming routine, instead of the use of polluting single-use plastic bags. However, this is controversial in terms of food safety, since consumers transport many different foods, which could contaminate their bags and pose a risk to their health due to cross-contamination. This study aimed to detect or enumerate several indicators/pathogens from 30 used reusable plastic (polypropylene) bags and, to evaluate their antibiotic resistance profiles after identification by 16s rRNA of each isolated microorganism. Several genera of Enterobacteriaceae, coagulase-negative staphylococci and also Listeria monocytogenes were found in the reusable plastic bags analyzed. In general, high percentages of antibiotics resistance were found, highlighting the elevated occurrence of multi-resistant isolates of coagulase-negative staphylococci and Enterobacteriaceae. This study demonstrates the level and variety of microbial contamination of some used reusable plastic bags. No correlation was found between microbial levels and the visual appearance of each bag demonstrating that appearance is not a reliable datum about the bag contamination. We believe that this study could help the competent authorities taking measures to alert consumers to good food safety practices, not only in their kitchens, but also in the bags that carry their food.
- Influence of oregano essential oil on the inhibition of selected pathogens in “alheira” during storagePublication . Carvalho, Marta I. P.; Albano, Helena C. P.; Teixeira, Paula C. M.Background. Plant-derived essential oils (EOs) have shown remarkable antimicrobial potential against spoilage and pathogenic microorganisms in meat and meat products. The aim of this study was to investigate the influence of oregano EO on the inhibition of Salmonella Enteritidis, Listeria monocytogenes and Staphylococcus aureus in an internal mixture of "Alheira" during storage. Material and methods. Different concentrations of oregano EO (4%, 1.5%, 0.5%, 0.195% and 0.0975%) were evaluated against the selected pathogens during 21 days of storage at 4 degrees C. The pH and water activity values and lactic acid bacteria (LAB) counts were also evaluated. Finally, sensory assessment was performed. Results. The antibacterial effect varied according to the oregano EO concentration used, and target pathogen. Oregano EO at 4% demonstrated the highest antimicrobial activity against all the pathogens tested. The lowest concentrations used (0.195% and 0.0975%) resulted in similar to 2-3 log reduction, but only for L. monocytogenes after 21 days of storage. Counts of LAB were similar to 10(9) CFU/ml for all samples and no differences in the pH and a(w) values were detected between samples. However, at a concentration of 0.195%, Oregano EO had a negative impact on consumer acceptance of "Alheira". Conclusion. These results could be interesting for the meat industry, as a starting point for other studies that have now to concentrate on strategies to "mask" unpleasant sensorial alterations caused by EOs in "Alheira" and helping the industry to ensure the microbiological safety of its products.
- Non meat-based alheiras - a safer novel trend?Publication . Azevedo, Inês; Barbosa, Joana; Albano, Helena; Teixeira, PaulaIn response to nutritional and health concerns, the food industry has begun to offer a wider variety of products that reflect changing consumer preferences. In addition to traditional alheiras, made with pork and/or poultry meats, other varieties of alheiras (“innovative”) made from codfish, mushrooms, tofu, soy and vegetables were launched on the Portuguese market. The objective of this study was the characterisation of these products, giving particular attention to their microbiological and chemical safety. Therefore, fourteen different products were analysed. Enterobacteriaceae, Enterococcus, lactic acid bacteria, yeasts and moulds, were the prevalent microbiota of “innovative” alheiras. Sulphite reducing Clostridium spores, Escherichia coli, Listeria monocytogenes, Salmonella spp. or Staphylococcus aureus were not detected in any sample. No differences were observed between traditional and “innovative” alheiras concerning pH and water activity values while nitrites, nitrates and biogenic amines were found to be within accepted limits for these kinds of products. In terms of organic acids, lactic acid was found in all analysed samples while malic and succinic acid seemed to be predominant only in “innovative” alheiras. In conclusion, unlike traditional alheiras which often contain pathogenic agents, no harmful organisms nor chemical hazards were found in these new products, even though produced by the same companies.