Preservation of foods by natural and microbiological methods may be a satisfactory approach solving economic losses due to microbial spoilage of raw materials and food products, nowadays bacteriocin from lactic acid bacteria offer a potential application in food industry as natural preservatives.The crude bacteriocin of Lb. acidophilus was purified to apparent homogeneity using a three step purification protocol which ammonium sulphate precipitation, gel filtration on a Sephadex G-75 column and Reversed Phase High Performance Liquid Chromatography. Then characterization of the purified bacteriocin at different pH values, heat treatments, proteinase K. The molecular weight of purified bacteriocin was estimated on SDS PAGE and obtained single protein band at 52 K.Da.The current study concluded that the purified bacteriocin of Lb. acidophilus DSMZ20079 should have much attention as it could be another dietary adjunct to be approved by the international communities as its commercial application is still limited. It plays an important role in controlling the total bacterial count, aerobic-spore formers and psychrotrophic bacterial counts in pasteurized milk. Moreover, it can extend shelf-life of pasteurized milk up to 15 days of storage.