The production of killer toxins is a widely distributed phenomenon among yeast (Antunes and Aguiar, 2011). Therefore, the killer activity/sensitivity phenotype was tested for all strains of yeast (Table 2). The reference killer-positive strain (S. cerevisiae CECT 1893) inhibited all strains under study, exceptS. cerevisiae ITD-00185 and K. marxianusITD-00147. These two strains can be considered to have the neutral killer phenotype because they did not inhibit the killer-sensitive strain (S. cerevisiaeCECT 1407) or any other native strains. The other selected strain,Torulaspora delbruekii ITD-00014a, did not inhibit any other strain, and the killer-positive strain CECT 1893 was the only strain to inhibit ITD-00014a. Finally, the selected strains did not shown cross-inhibition. Thesefindings reinforce the selection of these three yeasts for further study.