Applied Microbiology and Biotechnology

, Volume 27, Issue 5–6, pp 437–442 | Cite as

Heat-stable proteases of psychrotrophic bacteria isolated from cooled raw milk

  • Roger Poffé
  • Wim Mertens


143 psychrotrophic bacteria were isolated and identified from 53 cooled raw bulk milk samples. The most encountered isolates were Pseudomonas fluorescens and P. fluorescens-like organisms, Achromobacter xylosoxidans, Acinetobacter lwoffii, Aeromonas hydrophila and enterobacteria. The strongest activity was displayed by the pseudomonads, especially the P. fluorescens-like organisms. All the excreted proteases examined were heat-stable: the best inactivation was obtained after a heat-treatment of 1 h at 55°C and 2 min at 140°C. At temperatures of 80, 90 and 100°C often increasing heat-resistance was observed.


Pseudomonad Milk Sample Acinetobacter Strong Activity Pseudomonas Fluorescens 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag 1988

Authors and Affiliations

  • Roger Poffé
    • 1
  • Wim Mertens
    • 1
  1. 1.Laboratory of Industrial MicrobiologyCatholic University of LeuvenHeverleeBelgium

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