Feasibility of 3D UV-C treatment to reduce fungal growth and mycotoxin loads on maize and wheat kernels

Abstract

Fungal disease of grain crops is a concern for the agricultural industry, resulting in economic losses. Aside from severe yield losses, mycotoxigenic fungi such as Penicillium and Fusarium can produce harmful mycotoxins, including deoxynivalenol (DON), zearalenone (ZEN), and ochratoxin A (OTA). This proof-of-concept study explored the feasibility and effects of ultraviolet (UV) C light at 253.7 nm to reduce fungal and mycotoxin loads on model surfaces as well as on maize and wheat kernels using benchtop 2D and 3D illumination strategies. Reduction of Penicillium verrucosum (98.6%) and Fusarium graminearum (88.8%) on agar was achieved using a UV-C dose of 100 mJ cm⁻². Naturally occurring fungal growth resembling P. verrucosum on maize was reduced by 79% after exposure to 5000 mJ cm⁻². Similarly, fungal growth resembling F. graminearum on maize was reduced by 60% with 1000 mJ cm⁻². On wheat, significant reduction of fungal growth was not observed. Maximal reduction of DON (97.3%), ZEN (75.4%), and OTA (91.2%) on filter paper was obtained using 15,000 mJ cm⁻². The overall reduction of DON (30%; 14%), ZEN (52%; 42%), and OTA (17%; 6%) on maize and wheat, respectively, was lower than on filter paper. Moisture and crude protein content as well as percent germination of maize kernels were not affected by UV-C treatment up to 5000 mJ cm⁻². This study has shown that 3D UV-C treatment is a feasible option for reducing Fusarium and Penicillium growth on maize kernels and, at higher doses, decreasing ZEN by ~ 50%.