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- Microbiological quality of Portuguese yogurtsPublication . Nogueira, C.; Albano, H.; Gibbs, P.; Teixeira, P.The microbiological quality of four brands of natural yogurts and two probiotic yogurts available in the Portuguese market, was evaluated during the shelf-life period. Although the specific flora decreased during storage it was always within the range of recommended values. No coliforms and an insignificant number of fungi were detected.
- 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.
- Effects of lactobacillus plantarum bacteriocinogenic culture on physicochemical, microbiological, and sensorial characteristics of "Chouriço Vinha d'Alhos", a traditional Portuguese sausagePublication . Macieira, A.; Barros, D.; Vaz Velho, Manuela; Pinheiro, R.; Fonseca, S.; Albano, H.; Teixeira, P.Background: “Chouriço Vinha d’Alhos” is a traditional fermented dry meat sausage from North of Portugal. The aim of this work was to evaluate the effects of a fresh and a lyophilized bioprotective Lactobacillus plantarum ST153Ch culture, on an industrial scale, on the physicochemical, microbiological, and sensorial characteristics of “Chouriço Vinha d’Alhos”. Methods: “Chouriço Vinha d’Alhos” added with Lb. plantarum ST153Ch (fresh or lyophilized) were analyzed for the physicochemical, microbiological, and sensorial characteristics, over 90 days of storage at 4 ºC. All data were statistically analyzed using an ANOVA procedure by IBM SPSS Statistics v. 25. Results: The results showed that there was no difference in the reduction of L. monocytogenes, without or with the addition of Lb. plantarum either fresh or lyophilized. There were no significant differences (p>0.05) in some analyzed physicochemical parameters of products added with fresh or lyophilized Lb. plantarum cultures over the 90 days of storage; but both, fresh and lyophilized cultures, influenced some of the tested physicochemical parameters. Conclusion: Considering no significant differences between application methodologies (fresh or lyophilized Lb. plantarum), industry might be able to choose the most suitable method according to their manufacturing process.
- In vitro antimicrobial activities of various essential oils against pathogenic and spoilage microorganismsPublication . Carvalho, M.; Albano, H.; Teixeira, P.Background: Plant-derived Essential Oils (EOs) have shown remarkable antimicrobial activity against spoilage and pathogenic microorganisms isolated from food products. The objective of the current study was to determine in vitro antimicrobial effects of selected EOs against these microorganisms. Methods: Antimicrobial activity of EOs against food-borne and spoilage microorganisms was screened by disk diffusion assay; then, the Minimum Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) were determined. Statistical analysis was done using SPSS 23.0 software for Windows. Results: Oregano and thyme EOs showed the highest antimicrobial activity and the lowest MICs, while anise, fennel, garlic, and ginger showed a lower activity with significant differences (p<0.05). It was demonstrated that Salmonella Typhimurium, Escherichia coli, Proteus mirabilis, and Yersinia enterocolitica were the most sensitive bacteria to all the EOs tested (p<0.05). Among Gram-positive bacteria, Listeria innocua was demonstrated to be the most sensitive to most of the EOs (p<0.05). Furthermore, Staphylococcus aureus and Listeria monocytogenes were shown to be more sensitive than Enterococcus spp. (p<0.05). Yeasts were significantly (p<0.05) more sensitive than bacteria and were inhibited by most of the EOs. Conclusion: The use of the analyzed EOs may be interesting to food processors because of their antimicrobial properties. However, it is necessary to test their use in food products and gauge their sensory implications.
- Listeria: is it a problem?Publication . Barbosa, J.; Ferreira, V.; Albano, H.; Magalhães, R.; Santos, I.; Castro, A.; Silva, J.; Almeida, G.; Teixeira, P.
- The effect of the addition of fresh and dried starter cultures on microbiological and chemical parameters of a smoked sausage “Alheira”Publication . Barros, D.; Velho, M. Vaz; Pinto, R.; Pinheiro, R.; Fonseca, S.; Macieira, A.; Albano, Helena; Morais, A. M.; Teixeira, P.
- Case report of clinical salmonellosis by salmonella typhimurium that occurred in portuguese childrenPublication . Freixo, R.; Albano, H.; Silva, J.; Teixeira, P.Aims: Aim of this study is to characterize clinical isolates of Salmonella Typhimurium that occurred in Portuguese children on the basis of their virulence and antimicrobial resistance profiles and pulsed-field gel electrophoresis typing and to analyse possible strain relatedness. Methods and Results: Different Salmonella serotypes were isolated from clinical cases of salmonellosis that had occurred in two Portuguese hospitals (a total of 259 isolates). All Salm. Typhimurium strains, with the age of the patients known, (total of 26 isolates) were selected for this study. These isolates were characterized for their virulence gene profiles (agfA, iroB, slyA, hin/H2, spv), antimicrobial resistance profiles and investigated for the occurrence of multi-drug-resistant Salm. Typhimurium DT 104 by PCR. Salmonella isolates showed high rates of resistance to four or more antibiotics, 100% resistance to sulfadiazine and a high percentage of strains with the resistance profile of Salm. Typhimurium DT 104, two of them with this phage type (determined by PCR). A relationship between some clusters and their resistance and virulence profiles was detected, each cluster having the same profile. Conclusions: This study showed high-antibiotic resistance of the Salmonella strains investigated, and the presence of multidrug-resistant Salm. Typhimurium DT104 in infections of Portuguese children. Significance and Impact of the Study: Study is based on regarding the increase in antibiotic resistance by Salmonella strains isolated from infections in Portuguese children and on the presence of Salm. Typhimurium DT 104 circulating in Portugal.
- Antibiotic resistance of Enterobacteriaceae isolated from the domestic food related environmentsPublication . Azevedo, I.; Albano, H.; Silva, J.; Teixeira, P.Background: Multidrug resistant Enterobacteriaceae which was confined to the hospital environments is now emerging in the domestic food related environments as well. The main objective of the present study was to investigate the prevalence of antibiotic re-sistant Enterobacteriaceae in the domestic food related environments. Methods: Resistance to ampicillin, chloramphenicol, ciprofloxacin, gentamicin, tetracy-cline, nalidixic acid, nitrofurantoin, and trimethoprim was evaluated in 125 isolates; col-lected in domestic food related environments using agar micro dilution method. Results: Results indicated that 49.6% of the isolates were resistant to at least one antibi-otic (32.8% to ampicillin, 6.4% to nitrofurantoin, 4% to tetracycline, 3.2% to nalidixic acid, 2.4% to chloramphenicol and 1.7% to trimethoprim). Resistance to multiple antibi-otics was observed in 6.4% of the isolates. Conclusion: This study implicates existence of antibiotic resistant Enterobactericeae in the domestic food related environments. This resistance phenomenon requires continual vigilance; and further studies are required to evaluate the role of domestic surfaces in the transmission of resistant pathogens and spread of infectious diseases.