I work with food-borne pathogen as Yersinia enterocolitica and Shiga toxin producing Escherichia coli (STEC). Over more than 15 years I have been investigating the incidence of these bacteria species in different kind of food, mainly meat and it’s derivate. Moreover, in my laboratory we can perform phenotypic and genotypic characterization of the isolated strains. I have developed several PCR and RT-PCR for Yersinia identification in food and perform PFGE and ribotyping for clonal characterization. Nowadays, I am working with Yersinia and STEC biofilm, both characterization and inhibition. For characterization I have obtained quorum sensing mutants by homologue recombination and now I interested in knowing the influence of this communication system in the development of biofilm. For inhibiting biofilm, I am using alkaloids and naphtoquinones as natural compounds and try to establish their action mechanism.