Lactoside 247™ is an antimicrobial product for use in fuel ethanol fermentations. It contains a proprietary combination of antibiotics that inhibit the broadcast range of fermentation contaminants, including Lactobacillus, Acetobacter, Leuconostoc, and Pediococcus. The synergistic inhibition effect of multiple antibiotics provides greater inhibition at lower levels that other products and prevents the development of resistant contaminants. Eliminating infection prevents competition for glucose, reduced yeast, stress, and increases alcohol levels. LACTOSIDE 247 is stable over a broad pH range and is effective immediately. It can be added to the yeast propagator or to the fermenter at the beginning, middle or end of fermentation.