“…This is due to the non-chromosomal killer genom loss or mutation (Wickner, 1974). The occurrence of killer phenotype in yeasts is widespread in alcoholic fermentations for beverage production such as in breweries (Maule and Thomas, 1973), saké (Imamura et al, 1974;Ouchi et al, 1979), wine (Naumov et al, 1973;Thornton, 1986;Petering et al, 1991;Sulo and Michalcáková, 1992;Carrau et al, 1993) and recently in sugarcane producing plants (Sato et al, 1993;Morais et al, 1997;Ceccato-Antonini et al, 1999;Sato, 1999, 2000). Many of these fermentative processes use non-pasteurised medium, which can allow the predominance of wild yeast strains coming from the raw material outnumbering the starter yeast.…”