Disclosed is a method for producing partially purified extracellular metabolite preparation from the probiotic bacterial strain Bacillus coagulans SBC-37 (Deposited in the Microbial Type Culture Collection and Gene Bank as strain number MTCC 5856) exhibiting 99% genetic homology with the known bacterial strains Bacillus coagulans ATCC 31284, Bacillus coagulans NBRC 3887 and Bacillus coagulans ATCC 7050. Also disclosed is the anti-microbial profile of said extracellular metabolite preparation against a panel of microbial pathogens, including synergistic anti-microbial effects of preparation when combined with a synergistic preservative blend comprising from about 61% w/w of thymol, about 38% of monolaurin and about 1% w/w of magnolol obtained from supercritical fluid extracts of Magnolia officinalis. The extracellular metabolite preparation alone or the combination of said extracellular metabolite preparation and preservative blend also inhibits microbial biofilm formation in a synergistic manner.