In many developed and developing countries, sedulous trails are running for achieving high quality dairy products without using chemical preservatives. Microbial metabolites, such as that produced by Propionibacteria are coming in need to achieve such an aim. Therefore, utilization of permeate supplemented with different nutrients to improve production of metabolites under controlled conditions in a fermentor was studied. Metabolites of Propionibacterium thoenii P-127 proved to have an antimicrobial activity against the tested microorganisms. Permeate supplemented with casein hydrolysate supported maximum production of antimicrobial substances by P. thoenii. Antifungal activity of lyophilized metabolites stored at 25^oC showed a drop of activity (approximately 25%) compared to metabolites stored at 4^oC. The addition of lyophilized P. thoenii P-127 metabolites by 1.5% to Domiati cheese milk obviously prolonged the shelf-life of soft cheese. The investigators proposed the name “Propiogard” for the product, to differentiate it from commercial name “Microgard”.