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Modelling the effectiveness of a natural antimicrobial on Salmonella enteritidis as a function of concentration, temperature and pH, using conductance measurements
Author(s) -
Koutsoumanis,
Chrysoula C. Tassou,
Taoukis,
GeorgeJohn E. Nychas
Publication year - 1998
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.1998.00433.x
Subject(s) - salmonella enteritidis , antimicrobial , microbiology and biotechnology , salmonella , conductance , biology , chemistry , food science , bacteria , mathematics , genetics , combinatorics
The growth of Salmonella enteritidis in a brain heart infusion medium was monitored using the traditional viable count method and by conductance measurements using a Rabit impedance instrument. Growth curves (log 10 cfu ml −1 vs time) at three different concentrations of oleuropein (0, 0·2 and 0·8%), pH values in the range of 5–8 and incubation temperatures from 22 to 42 °C were modelled using the Gompertz equation. A good correlation between the maximum growth rate from the viable count method and the maximum slope of the conductance curve from the impedance instrument was established. Based on this correlation, the maximum specific growth rate of Salm. enteritidis was modelled as a function of the oleuropein concentration, initial pH values and the incubation temperature with a quadratic equation, using a new, larger dataset of growth measurements by conductance. The developed model was validated by statistical comparison of predicted growth rates with growth rates determined by the viable count method, within the limits of the antimicrobial, pH and temperature domain.