Effect of High Intensity Ultraviolet Light (UV-A) Emitting Diodes Technology on the Reduction of Mycotoxins in Whole Milk: Kinetic and Cytotoxicity Study

The effectiveness of a UV-A light emitting diode system (LED) to reduce the concentrations of aflatoxin B1, aflatoxin M1 (AFB1, AFM1) in whole milk (WM) was investigated. Irradiation experiments were conducted using an LED system operating at 365 nm. Known concentrations of aflatoxins were spiked in WM and irradiated at quantified UV doses which was calculated based on the average volumetric intensity. LC-MS product ion scans were used to identify and semi-quantify photodegraded products of AFB1 and AFM1. It was observed that UV irradiation significantly reduced aflatoxins in WM (p \u3c 0.05). In comparison to control, the maximum UV-A exposure reduced AFB1 and AFM1 concentrations to 78.2 ± 2.36 % (at 836 mJ/cm2) and 65.7 ± 1.65% (at 857 mJ/cm2), respectively. In cytotoxicity studies, our results demonstrated that the increase in UV-A dosage decreased the aflatoxins-induced cytotoxicity in HepG2 cells, and no significant aflatoxin-induced cytotoxicity was observed at the highest given UV-A irradiation of 777 (AFB1), 838 (AFM1), and 746 (total AFs) mJ/cm2. Tryptophan (TRP), glutamic acid (GLU), lysine (LYS), glutamine (GLN) and lipid peroxidation were assessed in UV-A irradiated WM. No significant reduction in amino acids was observed, p\u3e0.05. At 279 mJ/cm2 no significant lipid peroxidation was observed. In contrast, minor changes lipid peroxidation was observed 838 mJ/cm2, p\u3c0.05. The volatile profiling showed that alcohols, the key contributor of oxidized flavor was not significantly affected by the UV-A irradiation. Western blotting was used to assess the effect of UV-A irradiated WM on protein expression in HepG2 cells. Because the targeted gene p53 was not considerably altered, we can affirm that UV-A irradiated WM was safe from toxins that leads to oxidative cell stress. This is indicating substantial breakdown of AF in WM by UV-A as well as no accumulation of toxic components from protein, lipid, and FAA degradation. This study clearly demonstrated the efficacy of UV-A LED system in reducing AF in WM below Food and Drug Administration recommended limits. Investigating the cytotoxicity, and mutagenicity of UV exposed aflatoxins in WM using animal model is warranted in the future