Premium
Non‐linear modelling and statistical anlaysis of multi‐stage high‐pressure inactivation of lactic acid bacteria
Author(s) -
Kilimann Klaus Valentin,
Hartmann Christoph,
Gänzle Michael,
Delgado Antonio
Publication year - 2005
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.200510312
Subject(s) - lactococcus lactis , degree celsius , lactic acid , chemistry , streptococcaceae , bacteria , food science , metabolic activity , biochemistry , biological system , biology , thermodynamics , genetics , physics , antibiotics
Abstract It was the aim of this work to determine the combined effects of pressure, temperature, and co‐solvents on Lactococcus lactis , and to detect correlations between culture‐dependent and culture‐independent methods for assessment of cellular viability and sublethal injury. Therefore, the pressure induced inactivation of L. lactis MG 1363 was investigated in 21 buffer systems at a pressure range of 0.1 MPa to 600 MPa and a temperature range of 5 to 50 Grad Celsius. The inactivation was characterised by viable cell counts, stress resistant cell counts, membrane integrity, metabolic activity, and LmrP activity. By using Principal Component Analysis, correlations were detected between viable cell counts and metabolic activity as well as stress resistant cell counts and LmrP activity. Based on these correlations, a fuzzy logic model was formulated. The model uses two of the five physiological states as autonomous output variables. Input variables are pressure, temperature, application time and food systems. Latter fully describe the inactivation process of L. lactis correctly. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)