Immobilized lactase and glucose oxidase were used to produce H2O2to activate the lactoperoxidase system in milk. The enzymes were immobilized on nylon pellets. With a ratio of 35 g of catalyst/L of milk, a concentration of 0.75 mM was produced in 3 min. Raw milk treatment with the catalyst reduced coliforms by 79%;Staphylococcus aureusreduction was 68%, psychrotrophs 91%, and fungi 100%. Results were similar when milk was treated by addition of H2O2. Thiocyanate was not limiting because addition of NaSCN did not increase the effectiveness of the lactoperoxidase system.