Effect of Temperature, pH and Water Activity on Penicillium digitatum Growth

Abstract

Growth curves fitted Penicillium digitatum were used to analyze the effect of temperature, pH and aw on their growth. To asses observance of independent variable effects on all growth parameters (λ, latency time, μ, growth rate and ymax maximal growth) a slow growth strain of P. digitatum was employed. Growth curves were obtained at different conditions of temperature (10?C - 40?C), pH (3.0 - 7.0) and water activity (0.800 - 0.990) and growth parameters were calculated by fitting of logistic model. Polynomial models were made by linear regression and all terms (linear, quadratic and interactive effects) were statistically significant (p < 0.001). All growth parameters, including maximal growth were affected by environmental conditions; pH effect was more important on maximal growth than that on lag time or growth rate. In some aspects results and modeling behavior of P. digitatum, are very similar to modeling of bacterial growth.