Abstract: This test adopted the tap water as the solvent. The conditions for extracting antimicrobial substance from the fruitof Common Macrocarpium have been researched. The optimum extracting condition is A3B2C1. The antimicrobial effect of thesubstance against food spoilage and food-borne pathogens was tested. The results showed that the substance could effectivelyinhibit the growth of bacteria, yet not so much to mould and yeast. The antimicrobial minimum dosage on different flora actedas 50%, and the pH range of inhibiting bacteria as 3～5. Moreover, the heat stability was good.

Key words: fruit of Common Macrocarpium, extracting, antimicrobe