Patent ID: 7618658

Claim:
A method for inhibiting growth of at least one microorganism selected from Propionibacterium comprising the steps of providing an anti-microbial agent comprising Sasa extract in an amount ranging from 1 to 50% by mass as expressed in terms of a solid content of the anti-microbial agent and contacting the microorganism to the anti-microbial agent, wherein the anti-microbial agent comprises an organic acid in an amount of from 0.01 to 5% by mass based on the total mass of the anti-microbial agent and said organic acid is selected from the group consisting of malic acid, citric acid, lactic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, acetic acid, benzoic acid, phenyl-acetic acid, salicylic acid and phenols, and wherein the Sasa extract is prepared by extracting raw leaves or dried leaves of Sasa with water maintained at a temperature ranging from 100 to 180° C. at ordinary pressure or while applying a pressure, or wherein the Sasa extract is prepared by extracting leaves of Sasa albo-marginata in a first extraction at a temperature ranging from 100 to 180° C. for 5 to 30 minutes using a pressurized hot water extraction device to obtain a first extract, separating the first extract from a moisture-containing solid content in a moisture separator, treating the moisture-containing solid content at a temperature ranging from 100 to 200° C. for 5 to 60 minutes in a saturated vapor-heating device, further treating the solid content thus treated in a second extraction at 100 to 180° C. for 5 to 30 minutes using a pressurized hot water extraction device to obtain a second extract and combining the extracts obtained in the first and second extraction steps, or wherein the Sasa extract is prepared by extracting dried leaves of Sasa albo-marginata with water heated to 60 to 100° C. for 30 minutes to 12 hours.