TECHNOLOGY FOCUS - BIOLOGY - Preferred Process: The process (M1) involves production of ethanol from starch or sugar using yeast as the fermentation agent; contacting unwanted bacteria with an effective amount of bacteriophage and/or bacteriophage derived products sufficient to reduce unwanted bacteria; and using bacteriophage virulent for bacteria capable of producing bacteriocin. The use of bacteriocin and bacteriophage are sequenced so that bacteriophage producing bacteria, if used in situ, are lysed after effective treatment with bacteriocin. The bacteriocin is applied in a cocktail, a panel, and/or multi-panel. The process (M1) involves contacting the reactants in the fermentation process with bacteriocin and bacteriophage prior to entering the fermentation stage for sufficient time to reduce unwanted bacteria. The feed reactant to a fermentation step of the fermentation process and the yeast entering the fermentation step are contacted with bacteriocin effective to reduce unwanted bacteria. The process (M1) also involves contact with bacteriophage virulent for bacteria capable of producing bacteriocin utilized in the process; contacting the unwanted bacteria with bacteria capable of producing bacteriocin virulent for the unwanted bacteria in a sufficient amount and for sufficient time for the bacteriocin bacteria to produce an effective amount of bacteriocin virulent for unwanted bacteria; and contacting unwanted bacteria with an effective amount of bacteriophage sufficient to reduce unwanted bacteria. The fermentation process is a fermentation process for conversion of sugars from a solution of sugars to ethanol comprising fermentation feed preparation steps, fermentation steps and yeast propagation steps, where unwanted bacteria in the sugar solution are contacted with bacteriocin and products of the yeast processing step is contacted with bacteriocin, where the bacteriocin in each case is tailored to the unwanted bacteria of the solution or product. The process (M2) involves fermenting sugar to ethanol; and contacting reactants in the process with bacteriocin and an effective amount of bacteriophage sufficient to reduce unwanted bacteria. In the process (M3), the bacteriocin-producing phage is incorporated into the fermentation process step to produce the desired bacteriocin in situ. Preferred Components: The unwanted bacteria are acid producing bacteria. The bacteriocin also comprises Nisin. The phage are of high burst size. EXAMPLE - No suitable example given.