Ultraviolet radiation and generally recognized as safe (GRAS) preservatives for inactivation of Aspergillus niger in vitro and corn dough

Abstract

Corn is the main cereal produced in the world, it is also used for direct human consumption and for the production of various food products; however, it is prone to being contaminated by fungi, especially by mycotoxin producers. Aspergillus spp. is a contaminant fungus related to postharvest of stored grains, especially in corn. This study evaluated the effect of Ultraviolet radiation (UV) and Generally Recognized As Safe (GRAS) treatments on the inhibition of mycelial growth of A. niger (GIBI_00056) in vitro and in corn (Zea mays L.) dough. For the in vitro study, UV radiation and solutions of citric acid, potassium sorbate, sodium bicarbonate, sodium benzoate, and ascorbic acid were used, which were added to PDA agar in which A. niger was inoculated and evaluated at 24, 48, and 72 h. Subsequently, the best treatment was selected and applied in different concentrations in an A. niger inoculated corn dough, thus evaluating the incidence of contamination at 24, 48, and 72 h. The sodium bicarbonate and sodium benzoate solutions had the best effect on the inhibition of A. niger in vitro compared to the control, whereas the other treatments evaluated did not show differences in the mycelial inhibition. In the corn dough inoculated with A. niger, the effect of sodium bicarbonate depended on the concentration used; the lowest incidence of contamination of the microorganism at 72 h was 0% with 1.8 and 2.7% (w/w) of sodium bicarbonate, whereas the highest was for the control with 100% incidence. The potential of sodium bicarbonate to inactivate A. niger growth in vitro and corn dough was observed.