Tehnike dekontaminacije zrna kukuruza od mikotoksina

Mycotoxins are known contaminants of food and feed and due to their toxic effects on humans and animals, they have become a great challenge in terms of food safety. Previous efforts to reduce mycotoxin exposure in Serbia have gone in the direction of detecting contaminated products to prevent their use, as well as applying adsorbents to reduce the intake of mycotoxins by animals. However, this study examined decontamination methods as a long-awaited improvement in battle against mycotoxins. Ultraviolet (UV), ozone and mechanical removal as decontamination techniques were applied to maize samples previously contaminated with deoxynivalenol (DON), zearalenone (ZEA), fumonisins (FUM) and ochratoxin A (OTA). The application of ozone involved the use of three different concentrations of ozone, to which contaminated maize was exposed during different time periods. Experiments on the application of UV radiation were done by applying radiation sources at two wavelengths, at different distances of maize from the radiation source and during different time periods. As a technique of mechanical removal of mycotoxins, the brushing method was applied. The results showed that the use of UV radiation and ozone for decontamination of naturally contaminated maize led to a decrease in DON content and the total number of infectious fungal particles, and that UVA radiation had the potential for DON degradation, but it was necessary to extend the irradiation process above 120 minutes. The application of UV radiation on artificially contaminated ground maize grain showed that short-wave UV radiation (λ = 254 nm) for 360 minutes did not achieve statistically significant reduction in the content of any of the tested mycotoxins. Nevertheless, these results represent the first report on the successful application of long-wave UV radiation (λ = 368 nm) when it comes to reducing the DON content in maize. However, long-wave UV radiation did not have a significant effect on the reduction of ZEA and OTA. This was supported by the fact that the application of the first-order kinetic model to UV irradiation reactions was only justified for the degradation of DON by the application of UVA radiation. In addition, decontamination of DON, ZEA and OTA using ozone in naturally contaminated ground maize grain proved to be the most effective in the case of OTA at the level of 70.3%. The content of ZEA was decreased by 68.1% and DON by 42.8%. To the best of our knowledge, this was the first report of the successful use of ozone for decontamination of maize naturally contaminated with three mycotoxins at the same time. Also, nonlinear regression analysis showed that the reaction of mycotoxindegradation by ozone in maize belonged to the first order chemical reaction. Comparative analysis of chromatograms of untreated samples and samples treated with ozone and UV radiation, suggested that there was no interference of peaks of possible degradation products with mycotoxin peaks in any case. Mechanical removal of FUM from maize grains by brushing proved to be effective after 90 seconds of application of this procedure. Shorter brushing times were found to be less effective at lower concentrations of these mycotoxins. The use of ozone was justified for the decontamination of ground maize grain contaminated with DON, ZEA and OTA, whereby this procedure was more efficient for the degradation of ZEA and OTA than DON. We believe that this procedure is the most suitable for decontamination of maize naturally contaminated with these mycotoxins, but that it would be useful to conduct further research on the optimization of ozone levels and exposure times. The application of UV radiation proved to be suitable for decontamination of maize only if it was contaminated with DON, but with a weaker effect compared to the application of ozone. However, the practical application of this procedure on larger quantities of maize would pose a challenge due to the long exposure time and the very thin layer that have to be irradiated. Mechanical removal has proven to be effective for decontamination of maize grain contaminated with FUM, although further research of this procedure should be directed towards the development of a technological solution for its practical application