Original scientific paper
Growth and proteolytic activity of Pseudomonas fluorescens isolated from milk
Irena Rogelj
; Biotehniška fakulteta, Oddelek za zootehniko, Institut za mlekarstvo, Groblje 3, 1230 Domžale, Slovenija
Abstract
The relation between growth kinetics of Pseudomonas fluorescens 33 and its proteolytic activity in raw and sterilized milk stored at 7° C was studied. Kinetics was determined by experimental growth curves. The proteolytic activity was measured by non-protein nitrogen (NPN), noncasein nitrogen (NCN) and tyrosine value (TV). The generation time of P. fluorescens 33 ranged from 7.9 hours to 11.1 hours and was shorter in sterilized milk. When population of P. fluorescens 33 reached stationary phase (10^8 CFU/ml) strong proteolytic activity was observed. During six days of storage the amount of NCN increased from 120 mg/100 g to 280 mg/100 g.
Keywords
Pseudomonas fluorescens activity; raw milk; sterilized milk; poteolytic activity; milk storage (7 °C)
Hrčak ID:
95531
URI
Publication date:
12.12.1992.
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