Effects of climatic conditions and hermetic storage on the growth of Aspergillus parasiticus and aflatoxin B1 contamination in basmati rice

Abstract

Climate change has influenced the growth of Aspergillus species and subsequent aflatoxins (AFs) production. In this study, the combined effect of temperature (20–40 °C) with respect to moisture content (MC = 7–25%) and water activity (aw = 0.86–0.98) on the growth of A. parasiticus and aflatoxin B1 (AFB1) occurrence was studied in basmati rice. The effect of hermetic storage on AFB1 occurrence was also investigated. The growth of A. parasiticus and the AFB1 production were found between 15 and 25% MC and 0.92–0.98 aw at 25–35 °C. The optimum production of these entities with 25% MC or 0.95 aw at 30 °C was noticed. However, the lower temperature (<20 °C), MC (<10%) and aw (<0.86) doesn't support the growth of A. parasiticus and AFB1 production. The production rate of the fungi and their metabolite were found in the following increasing order 30° > 35° > 25° > 20° > 40 °C at all tested MC and aw levels. The growth of A. parasiticus and AFB1 production were found as increasing trend 25% > 20% > 15% > 10% at all tested temperature. Whereas, the fungal growth and AFB1 production with respect to aw were seen in the increasing order 0.95 ˃ 0.98 ˃ 0.92 ˃ 0.89 ˃ 0.86 aw at all tested temperatures. The storage of rice samples in a hermetic bag, the significant control (less than 90% AFB1 production compared with normal conditions) the AFB1 production in rice. The results also indicated that the growth of A. parasiticus and AFB1 production were significantly (p <0.05) affected by the temperature, MC and aw, as well as the storage conditions in normal and hermetic bags as analyzed using ANOVA. In conclusion, hermetic storage is experimentally proved as the best way of storing cereals and grains for a long time.