Lactobacillus pentosus C50-6,isolated from traditional Sichuan fermented meat products,produces a bacteriocin,pentocin C50-6.The bacteriocin was purified by ammonium sulphate precipitation and Toyopearl SP-650M cation-exchange column.The purification resulted in a yield of 21.76% of the original activity and a 39.15-fold increase in specific activity.The estimated molecular weight of pentocin C50-6 was approximately 2.5 ku based on Tricine-SDS-PAGE,in which bacteriocin activity was confirmed by overlayer techniques were in accordance with this value.The bacteriocin was heat resistant(121°C for 20 min),active at pH values between 2.0~6.0 and inactivated by papain,trypsin and proteinase K.The bacteriocin demonstrated inhibitory activity towards some species of Gram-positive,Gram-negative bacteria and minority of fungus tested,but was not active against majority of lactic acid bacteria.These results indicate that pentocin C50-6 may have potential for use as food preservative.