The definitive version is available at www.blackwell-synergy.com.A set of 120 isolates of Lactobacillus (75), Lactococcus (25) and Leuconostoc (20), mainly isolated from natural starter-free fermentation processes, has been screened for some technologically important traits, including lactose hydrolysis, extracellular polysaccharide production, fermentation of carbohydrates, antimicrobial agent susceptibility and bacteriocin production. Some of the strains exhibited important features for particular fermentations. Furthermore, the sensitivity resistance phenotype to antimicrobials showed genus-specific patterns.This work was supported by grant BIOT-CT91-0263 of the BRIDGE Programme fron the European Community and grant ALI90.0233 from DGICYT of the Spanish Ministry of Education. BG and MH were the recipients of a predoctoral fellowship from the Spanish MInistry of Education and the Fondo de Investigación Científica y Técnica of Asturias, respectively.Peer reviewed