Growth modeling kinetics of Alternaria alternata in dried jujube at different temperatures

Abstract

Alternaria alternata is a fungus that infects jujube, causes black spot disease, and produces Alternaria mycotoxins, such as alternariol, alternariol monomethyl ether, and tenuazonic acid. This study aimed to apply models to predict growth and mycotoxin production by A. alternata isolated from jujube as a function of temperature and water activity. The practicability of the model was verified on jujube agar medium. The growth conditions were water activity of 0.99 or 0.90 a_w and temperatures of 10, 15, 20, 25, 30, or 35 °C. The growth rate of A. alternata was highest at 0.99 a_w and 25 °C, and the lag time was the shortest at 0.90 a_w and 30 °C. The dry weight growth rate of mycelia increased gradually with the increase of temperature on PDA and jujube agar medium. Mycotoxin production by A. alternata was not correlated with growth, but no significant delay was detected in some cases. In general, the growth model predicted the growth of A. alternata.

Keywords:
Alternaria alternata; Alternaria mycotoxins; predictive modeling