The invention relates to the field of bacteriocin producing microorganisms. The invention more specifically relates to the characterization of a novel food grade bacteriocin, namely a lantibiotic, named macedocin and produced by Streptococcus macedonicus ACA-DC 198. Macedocin inhibit a broad spectrum of lactic acid bacteria as well as several food spoilage and pathogenic bacteria, among others Clostridium tyrobutyricum, and is heat stable and active in a broad pH range. The invention further relates to the use of non-pathogenic microorganisms for producing macedocin in food fermentation processes, such as for preparing milk products, butter, cheese and fermented meat and vegetables, as well as in non-fermented food products such as raw meat, modified atmosphere-packed meat products, ready-to-eat meals, and canned food products, and its use for the preparation of functional starter cultures and cocultures.