Study of Proteolytic and Lipolytic Activities of Pseudomonas spp. Isolated From Pasteurized Milk in Tunisia

Abstract

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 (30) pasteurized milk samples were collected aseptically from different dairy shops, supermarkets and groceries in different areas in Sfax Governorate, Tunisia and analyzed for total viable count and Pseudomonas spp. occurrence and explain their proteolytic and lipolytic activities. The results showed that Pseudomonas aeruginosa was found to be the predominant from the Pseudomonas spp. followed by Pseudomonas fluorescens. The total viable count was (3.25 ± 0.02) × 104 CFU/ml. Out of 8 Pseudomonas spp. isolates that were examined for proteolytic and lipolytic activities; two isolates had proteolytic activity, while two had lipolytic activity and four isolates had both.