Protease and Lipase Activities of Pseudomonas Spp. Isolated from Pasteurized Milk

Document Type : Original Article

Author

Department of Industrial Biotechnology, Genetic Engineering and Biotechnology Research Institute, Menuofiya University, Egypt.

Abstract

Raw milk deteriorates in only a few days even when stored under refrigeration temperatures. Moreover,
pasteurized and refrigerated milk has a shelf life of 7 to 10 days. Psychrotrophic bacteria have been recognized as a recurring problem in refrigerated storage and distribution of perishable food products. This study was performed to isolate, characterize and evaluate the prevalence of Pseudomonas spp. in pasteurized milk. Thirty five pasteurized milk samples were collected aseptically from different dairy shops, supermarkets and groceries in different areas in Sadat city, Menuofiya Governorate, Egypt and analyzed for total viable count and Pseudomonas spp. occurrence. Pseudomonas aeruginosa found to be the predominant from the Pseudomonas spp. followed by Pseudomonas fluorescens. The total viable count ( cfu per ml) average ± SD were 3.50× 104 cfu /ml ± 0.085. Out of ten Pseudomonas species isolates were examined to its proteolytic and lipolytic activity, two isolates had proteolytic activity, while three had lipolytic activity and five isolates had both.

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