Predictive Modeling for the Growth of Listeria monocytogenes as a Functionof Temperature, NaCl, and pH

초록

A mathematical model was developed for predictingthe growth kinetics of Listeria monocytogenes in tryptic soybroth (TSB) as a function of combined effects of temperature,pH, and NaCl. The TSB containing four different concentrationsof NaCl (2, 4, 5, and 10%) was initially adjusted to sixdifferent pH levels (pH 5, 6, 7, 8, 9, and 10) and incubated at4, 10, 25, or 37oC. In all experimental variables, the primarygrowth curves were well fitted (r2=0.982 to 0.998) to aGompertz equation to obtain the lag time (LT) and specificgrowth rate (SGR). Surface response models were identifiedas appropriate secondary models for LT and SGR on the basisof coefficient determination (r2=0.907 for LT, 0.964 for SGR),mean square error (MSE=3.389 for LT, 0.018 for SGR), biasfactor (Bf=0.706 for LT, 0.836 for SGR), and accuracy factor(Af=1.567 for LT, 1.213 for SGR). Therefore, the developedsecondary model proved reliable predictions of the combinedeffect of temperature, NaCl, and pH on both LT and SGR forL. monocytogenes in TSB.

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