CHARACTERISTICS OF PSEUDOMONAS SPP. FROM RAW MILK

Abstract

The genus Pseudomonas is a heterogeneous and ecologically important group of microorganisms, widely distributed in milk, water and the environment. They are classified as opportunistic pathogenic microorganisms for humans, animals and plants. The aim of this study was to examine the proteolytic, lipolytic activity and biofilm formation in isolates derived from milk. The material was pooled samples of raw milk from which isolates of Pseudomonas species (n=60) were isolated. Proteolytic ability was tested on nutrient agar with casein and lipolytic ability on Tributyrin agar. The ability of Pseudomonas species isolates to produce biofilm was tested in vitro by the Crystal Violet (CV) method on microtiter plates. In all 60 isolates of Pseudomonas spp. proteolytic and lipolytic activity from milk has been demonstrated. Isolates of Pseudomonas spp. originating from milk created a biofilm. Of the 60 isolates, 54 (90%) produced a biofilm of varying intensity, while 6 (10%) isolates did not produce a biofilm at all. The largest number, 42 (70%) of isolates of Pseudomonas spp. can be classified into medium-adherent isolates, 10 (16,67%) isolates as weakly-adherent and only 2 (3,33%) isolates as strongly-adherent isolates.
Isolates of Pseudomonas spp. from milk are good producers of biofilm, proteolytes and lipolytes so that they can cause rotten milk, and their finding is a consequence of contamination and poor hygiene conditions during the process of obtaining milk.