Influence of water activity and temperature on growth and mycotoxin production by Alternaria alternata on irradiated soya beans

► Environmental factors affect growth and mycotoxin production by A. alternata on soya beans. ► Maximum growth rates were obtained at 0.98 aW and 25 °C. ► Maximum amount of AOH and AME were produced at 0.98 aW and 15 to 25 °C. ► Two-dimensional profiles of aW x temperature were developed from these data. ► Range of aW during grain ripening supports optimal and sub-optimal growth and toxin formation.