A process for producing an antibacterial substance which comprises disintegrating at least a part of tissue of the plant with an enzyme capable of acting on protopectin to release and recover the antibacterial substance therefrom, while a pectin substance is removed; and antibacterial or bacteriostatic compositions containing the antibacterial substance thus obtained as the active ingredient. By using the above process and compositions, the proliferation of spore-forming bacteria and germination of spores from spore-forming bacteria and koji mold can be efficiently inhibited.