Ethanol production. Experiments conducted in MRS medium at pH 6 under (a) aerobic and (b) anaerobic conditions. Data are reported for cases where yeasts were grown alone (I); in the presence of bacteria at high inoculation level (II); and in the presence of bacteria at high inoculation level and phages B1 and B2 (III). Measurements for aerobic conditions were taken at 24 hours and for anaerobic conditions at 65 hours of fermentation. *Value was below the detection limit of 0.1% ethanol. Error bars indicate the standard deviation of three experiments.