Rapid Degradation of Aflatoxins by Treatment With Vacuum Ultraviolet Radiation Arising From Hydrogen Plasma

Abstract

A rapid, nonthermal method for surface decontamination of aflatoxins B1, G1, B2, and G2 was developed using vacuum ultraviolet (VUV) photons emitted from an inductively coupled hydrogen plasma. The plasma, sustained at 18 Pa with input powers between 50 and 700 W, produced intense VUV emission in the 140–160 nm range (photon energy ≈ 8 eV) that was delivered to samples through an MgF₂ window with > 80% transmittance. On quartz glass substrates coated with 40 ng of aflatoxin mix (film thickness ≈3 nm), VUV photons caused > 90% degradation within 10 s of VUV exposure. When applied to artificially contaminated maize grains (≈20 µg kg⁻¹ AFB1/G1, 4 µg kg⁻¹ AFB2/G2), VUV treatment achieved up to 80% toxin removal in under 1 min as measured by HPLC, but the remaining (≈20%) persisted even after 10 min of VUV irradiation, which was explained by the inability of VUV photons to penetrate into micron-scale grooves and crevices on the maize grain surface. These findings demonstrate that hydrogen-plasma VUV radiation can rapidly inactivate surface-bound aflatoxins on smooth substrates and agricultural commodities. However, the restricted penetration depth and vacuum chamber requirements limit bulk-grain scalability. Hybrid approaches combining VUV pretreatment with mechanical agitation and enzymatic degradation may offer a more energy-efficient, scalable solution for decontaminating porous food substrates.