The present invention relates to antimicrobial compositions which can be used in food preservation. The compositions according to the invention are based on the lactoperoxidase system (LPS), and comprise very low concentrations of lactoperoxidase, glucose oxidase, thiocyanate, and optionally glucose. The invention further relates to the use of such compositions, in particular in synergistic combination with heat treatment, in food preservation, methods for food preservation, and food products comprising these compositions.