ORIGINAL ARTICLE Potential beneficial properties of bacteriocin-producing lactic acid bacteria isolated from smoked salmon S.D. Todorov 1 , D.N. Furtado 1 , S.M.I. Saad 2 , E. Tome 3 and B.D.G.M. Franco 1 1 Faculdade de Cie ˆ ncias Farmace ˆ uticas, Departamento de Alimentos e Nutric ¸a ˜ o Experimental, Laborato ´ rio de Microbiologia de Alimentos, Universidade de Sa ˜ o Paulo, Sa ˜ o Paulo – SP, Brasil 2 Faculdade de Cie ˆ ncias Farmace ˆuticas, Departamento de Tecnologia Bioquı´mico-Farmace ˆ utica, Universidade de Sa ˜ o Paulo, Sa ˜ o Paulo – SP, Brasil 3 Instituto de Ciencia y Tecnologı ´a de Alimentos, Escuela de Biologı ´a, Universidad Central de Venezuela, Caracas, Venezuela Introduction The World Health Organization defines probiotics as live micro-organisms which, when administrated in adequate amounts, confer health benefits to the host such as reduc- tion in gastrointestinal infections and inflammatory bowel disease, and modulation of the immune system (Fuller and Gibson 1997; Galdeano et al. 2007; Oelschlaeger 2010). Probiotic strains survive the harsh conditions in the gas- tro-intestinal tract (GIT) and adhere to intestinal epithelial cells, forming a defence against colonization by pathogenic micro-organisms. Adhesion is inhibited by competition for adsorption to mucus and epithelial cells and, in certain cases, production of hydrogen peroxide and bacteriocins (Reid and Burton 2002; Galdeano et al. 2007). Changes in diet, stress, use of contraceptives or drugs and microbial Keywords bacteriocin, lactic acid bacteria, probiotic, salmon. Correspondence Svetoslav D. Todorov, Faculdade de Cie ˆ ncias Farmace ˆ uticas, Departamento de Alimentos e Nutric ¸a ˜ o Experimental, Laborato ´ rio de Microbiologia de Alimentos, Universidade de Sa ˜ o Paulo, Av. Prof. Lineu Prestes 580 Bloco 13B, 05508-000 Sa ˜ o Paulo – SP, Brasil. E-mail: slavi310570@abv.bg 2010 ⁄ 2074: received 16 November 2010, revised 22 December 2010 and accepted 13 January 2011 doi:10.1111/j.1365-2672.2011.04950.x Abstract Aims: To evaluate the probiotic properties of strains isolated from smoked salmon and previously identified as bacteriocin producers. Methods and Results: Strains Lactobacillus curvatus ET06, ET30 and ET31, Lactobacillus fermentum ET35, Lactobacillus delbrueckii ET32, Pediococcus acidi- lactici ET34 and Enterococcus faecium ET05, ET12 and ET88 survived conditions simulating the gastrointestinal tract (GIT) and produced bacteriocins active against several strains of Listeria monocytogenes, but presented very low activity against other lactic acid bacteria (LAB). Cell-free supernatants containing bacte- riocins, added to 3-h-old cultures of L. monocytogenes 603, suppressed growth over 12 h. Auto-aggregation was strain-specific, and values ranged from 7Æ2% for ET35 to 12Æ1% for ET05. Various degrees of co-aggregation with L. monocyt- ogenes 603, Lactobacillus sakei ATCC 15521 and Enterococcus faecalis ATCC 19443 were observed. Adherence of the bacteriocinogenic strains to Caco-2 cells was within the range reported for Lactobacillus rhamnosus GG, a well-known probiotic. The highest levels of hydrophobicity were recorded for Lact. curvatus (61Æ9–64Æ6%), Lact. fermentum (78Æ9%), Lact. delbrueckii (43Æ7%) and Ped. acidilactici (51Æ3%), which are higher than the one recorded for Lact. rhamnosus GG (53Æ3%). These strains were highly sensitive to several antibiotics and affected by several drugs from different generic groups in a strain-dependent manner. Conclusions: Smoked salmon is a rich source of probiotic LAB. All strains survived conditions simulating the GIT and produced bacteriocins active against various pathogens. Adherence to Caco-2 cells was within the range reported for Lact. rhamnosus GG, a well-known probiotic. In addition, the high hydrophobicity readings recorded define the strains as good probiotics. Significance and Impact of the Study: Smoked salmon contains a number of different probiotic LAB and could be marketed as having a potential beneficial effect. Journal of Applied Microbiology ISSN 1364-5072 ª 2011 The Authors Journal of Applied Microbiology 110, 971–986 ª 2011 The Society for Applied Microbiology 971