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- Phenotypic and genetic heterogeneity of lactic acid bacteria isolated from “Alheira”, a traditional fermented sausage produced in PortugalPublication . Albano, Helena; Reenen, Carol A. van; Todorov, Svetoslav D.; Cruz, Diana; Fraga, Luisa; Hogg, Tim; Dicks, Leon M.T.; Teixeira, PaulaThe aim of this study was to evaluate the phenotypic and genetic heterogeneity of lactic acid bacteria (LAB) isolated from ‘‘alheira”, a fermented sausage produced in Portugal. LAB were identified to genus and species level by phenotypic characteristics, using genus or speciesspecific primers and sequencing of the gene encoding 16S rRNA. Two-hundred and eighty-three isolates were grouped into 14 species. Lactobacillus plantarum was isolated from all sausages and Enterococcus faecalis from most of the samples. Low numbers of Lactobacillus paraplantarum, Lactobacillus brevis, Lactobacillus rhamnosus, Lactobacillus sakei, Lactobacillus zeae, Lactobacillus paracasei, Leuconostoc mesenteroides, Pediococcus pentosaceus, Pediococcus acidilactici, Weissella cibaria, Weissella viridescens and Enterococcus faecium were recorded. The genetic heterogeneity of L. plantarum and E. faecalis strains were determined by numerical analysis of DNA banding patterns obtained by RAPD–PCR. Strains of L. plantarum and E. faecalis were different from different producers. This study forms the basis from which starter cultures could be selected for production of ‘‘Alheira”.
- Screening of bacteriocinogenic lactic acid bacteria and their characterization as potential probioticsPublication . Pinto, Ana; Barbosa, Joana; Albano, Helena; Isidro, Joana; Teixeira, PaulaProbiotics are living microorganisms used as nutritional additives that confer health benefits on the host. Their use in food products is very attractive, especially if they could also inhibit important foodborne athogens. In this study, antimicrobial activity against several foodborne pathogens was screened for 280 lactic acid bacteria (LAB) isolated from di erent food products and the probiotic characteristics of bacteriocinogenic isolates were evaluated. Seven out of 280 LAB isolates were selected due to their bacteriocinogenic properties and identified by 16S rRNA gene sequence analysis as Pediococcus pentosaceus (n = 6) and Lactobacillus plantarum (n = 1). Virulence factors and antibiotic resistances were not detected for any of the isolates. Except for L. plantarum R23, all the isolates were able to survive through the simulated gastrointestinal tract conditions. Only P. pentosaceus CFF4 was able to adhere to Caco-2 cells after the simulated gastrointestinal tract passage. In conclusion, even though in vivo studies should be performed, P. pentosaceus CFF4, which was also able to inhibit the growth of foodborne pathogens in vitro, seems to be a potential probiotic to be used in the food industry.
- Antilisterial activity of lactic acid bacteria isolated from "Alheiras" (traditional Portuguese fermented sausages)Publication . Albano, Helena; Oliveira, Márcia; Aroso, Ricardo; Cubero, Núria; Hogg, Tim; Teixeira, PaulaA total of 226 lactic acid bacteria (LAB) isolated from ‘‘Alheira’’, a traditional Portuguese fermented sausage, were screened for antagonistic activity against some pathogenic microorganisms, including Listeria monocytogenes. The objective was to isolate LAB with antibacterial activity from ‘‘Alheiras’’ and to select strains that could be used in ‘‘Alheira’’ production. Isolates displaying antibacterial activity against Listeria innocua and L. monocytogenes were investigated for the nature of the antibacterial compounds active against these microorganisms. Results showed that two LAB cultures retained activity in the supernatants after neutralization and catalase treatment. These two strains were both identified as Pediococcus pentosaceus. The final aim of this work was to test the antilisterial activity of these two strains during storage of ‘‘Alheira mass’’ (sterilized), at 4 C. The growth of L. innocua population was significantly suppressed in the paste of ‘‘Alheira’’ when the samples were co-inoculated with the LAB strains, in comparison with the paste only inoculated with L. innocua or co-inoculated with a bacteriocin negative strain of Ped. pentosaceus (ca. 1 · 107 CFU/g after 28 days of incubation).