Mathematical Models to Predict Kinetic Behavior and Aflatoxin Production of Aspergillus flavus under Various Temperature and Water Activity Conditions

Abstract

Mathematical models were developed to predict fungal growth and aflatoxin production of Aspergillus flavus. Fungal growth and aflatoxin concentrations were measured. The Baranyi model was fitted to fungal growth and toxin production data to calculate kinetic parameters. Quadratic polynomial and Gaussian models were then fitted to mu(max) and LPD (lag phase duration) values. The ranges of temperature and a(w), values showing a mu(max) value increase were 15-35 degrees C and 0.891-0.984, respectively. LPD was only observed when the temperature was 20-35 degrees C with a(w)=0.891-0.972. The mu(max growth) value increased up to 35 degrees C with b(w)=0.2 (b(w)=root 1-a(w)), then values declined. LPDgrowth values increased as the b(w) value increased. The mu(max) value for aflatoxins increased up to 25 degrees C, but decreased after 30 degrees C, indicating that the developed models are useful for describing the kinetic behavior of Aspergillus flavus growth and aflatoxin production.