Description of a strain from an atypical population of Aspergillus parasiticus that produces aflatoxins B only, and the impact of temperature on fungal growth and mycotoxin production

Abstract

In this study, an atypical strain of Aspergillus parasiticus is described. This strain, reported from Portuguese almonds, was named Aspergillus parasiticus B strain. The strain is herein characterised at the morphological and physiological levels, and compared with the typical A. parasiticus strain and other similar species in section Flavi. Previously published morphological and molecular data support that the B strain is very closely related to the A. parasiticus type strain. However, while A. parasiticus typically produces aflatoxins B and G, B strain produces aflatoxins B only. Furthermore, this atypical strain showed to differ from the typical strain in the fact that higher growth (colony diameter) and aflatoxin B1 production were observed at 25 ºC than at 30 ºC, whereas the opposite was observed for the typical strain. This strain can become a major food safety concern in colder regions where the typical A. parasiticus strains are not well adapted.