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EFFECT OF THE PROTEASES OF MILK PSYCHROTROPH BACTERIA ON THE QUALITY OF DAIRY PRODUCTS.

ACTION DES PROTEASES DES BACTERIES PSYCHROTROPHES DU LAIT SUR LA QUALITE DES PRODUITS LAITIERS.

Author(s) : DOUSSET X., LEVESQUE A.

Type of article: Article

Summary

MILK MICROORGANISMS ARE INHIBITED BY COOLING EXCEPT PSYCHROTROPHS, ESPECIALLY PSEUDOMONAS OF THE FLUORESCENT GROUP. AT 277 K (4 DEG C) THESE MICROORGANISMS PRODUCE PROTEASES. THE SECRETION OF THESE IS MAXIMUM AT 293 K (20 DEG C), BUT IT REMAINS HIGH AT 278 K (5 DEG C). PROTEASE ACTIVITY IS OPTIMUM AT A TEMPERATURE OF 308-318 K (35-45 DEG C) AND AT A PH OF 6.5-8. ZINC AND CALCIUM HAVE AN ACTIVATING EFFECT: EDTA INHIBITS THEM. THESE ENZYMES ARE QUITE THERMORESISTANT: SOME STRAINS CAN RESIST 1 MIN AT 413 K (140 DEG C). THE PRESENT DETECTION MEANS, INSUFFICIENTLY SENSITIVE, DO NOT EVIDENCE A PROTEOLYTIC PSYCHROTROPH FLORA SMALLER THAN 5 MILLION CELLS/MILLIL.

Details

  • Original title: ACTION DES PROTEASES DES BACTERIES PSYCHROTROPHES DU LAIT SUR LA QUALITE DES PRODUITS LAITIERS.
  • Record ID : 1987-0199
  • Languages: French
  • Source: Ind. aliment. agric. - vol. 103 - n. 5
  • Publication date: 1986/05
  • Document available for consultation in the library of the IIR headquarters only.

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