Production of Hydrogen Peroxide by Lactobacillus acidophilus

Hydrogen peroxide production in reconstituted skim milk (10%) and low-fat milk by four strains lf Lactobacillus acidophilus was studied at 37 and 4 C. Strains A and B produced little, but strains C and D produced larger amounts, especially if agitated continuously during growth at 37 C or storage at 4 C. Continuous shaking was required at 4 C for C or D (4.0 X 10(8)/ml) to produce sufficient hydrogen peroxide to retard growth of Pseudomonas fragi. Flavin adenine dinucleotide stimulated the oxidation of reduced nicotinamide adenine dinucleotide by dialyzed cell-free extracts of C and D, which indicated that the reduced nicotinamide adenine dinucleotide oxidases of these strains produce hydrogen peroxide as an end product.