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 five (35) 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 and explain their proteolytic and lipolytic activities. The results showed thatPseudomonas aeruginosa was found to be the predominant from the Pseudomonasspp. followed by Pseudomonas fluorescens. The total viable count was (3.50 ± 0.085)´ 10⁴ cfu/ml. Out of 10 Pseudomonas spp. isolates that were examined for proteolytic and lipolytic activities; two isolates had proteolytic activity, while three had lipolytic activity and five isolates had both.

Key words: Pseudomonas aeruginosa, Pseudomonas fluorescens, proteolytic, lipolytic activities.