CERELA   05438
CENTRO DE REFERENCIA PARA LACTOBACILOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Isolation of bacteriocin-producing lactic acid bacteria from home-made Argentinian chesses
Autor/es:
SLOZILOVÁ I,; SUAREZ N, ; SAAVEDRA L, ; SESMA F, ; DENMEROVÁ K ; SVIRAKOVÁ E
Lugar:
Ginebra
Reunión:
Congreso; 4th Congress of European Microbiologists; 2011
Institución organizadora:
FEMS
Resumen:
Introduction: The antimicrobial properties of LAB strains are used to protect foodstuffs. The main reason is the production of lactic acid, which causes lower environmental pH and thus extends a shelf-life of food. Some LAB strains are known for production of bacteriocins. These antimicrobialcompounds are active at effective suppressing of growth of risk bacteria, which can be present in food in case of nonobservance of hygienic conditions during production. Aim: The aim of the work was the isolation of bacteriocin-producing LAB from home-made cheeses. Samples were bought in the countryside of the nothern part of Argentina, in the Tucuman province. Methods: Isolation of LAB was realized in three steps. Different types of following agars were used: BHI, MRS, LAPTG. Plates were cultivated at 37°C overnight. Firstly, typically looking colonies of LAB from the plates were separated from the other contamination. Secondly, the Gram-staining, the catalase test and the test of antimicrobial activity against risk strains (Listeria innocua, Enterococcus canis 33 and E. coli DH10) were carried out. Positive antimicrobially active strains were selected. In the last isolation step, modified supernatants (treated by catalase, proteinase K, NaOH and heating) of isolated LAB strains were tested against used risk strains to confirm the bacteriocin production. Genetic identification, used for the determination of species of isolated LAB strains, was carried out by the RAPD-PCR and DNA sequencing methods. Conclusion: During experiments, ten bacteriocin-producing LAB, identified as Enterococcus faecium species, were isolated. Antilisterial and/or antienterococcal activity were confirmed.