Combined effect of temperature and propionic acid concentration on the growth of Aspergillus parasiticus

Effects of temperature (25, 30 and 36 degrees C) and propionic acid concent ration (129, 258 and 516 ppm) on the growth of Aspergillus parasiticus in s olid media were analyzed. Growth rate, expressed as the increment of colony diameter per unit of time, was studied as a function of storage time emplo ying the Arrhenius model. The inverse of the lag phase was fitted to an Arr henius-type equation and the inhibition index was also calculated. A linear relationship between the lag phase and the reciprocal growth rate at diffe rent propionic acid concentrations was assessed by linear regression analys is. Fungi behavior was modeled considering the main controlling factors and a response surface methodology was established in terms of propionic acid and temperature. The proposed model could be used in food microbiology to p redict the growth of toxicogenic fungi growth. (C) 2000 Canadian Institute of Food Science and Technology. Published by Elsevier Science Ltd. All righ ts reserved.