Effect of gaseous ozone treatments on DON, microbial contaminants and technological parameters of wheat and semolina

Deoxynivalenol (DON) is an important mycotoxin produced by several species of Fusarium. It occurs often in wheat grain and is frequently associated with significant levels of its modified form DON-3-glucoside (DON-3-Glc). Ozone (O3) is a powerful disinfectant and oxidant, classified as GRAS (Generally Recognised As Safe), that reacts easily with specific compounds including the mycotoxins aflatoxins, ochratoxin A, trichothecenes and zearalenone. It degrades DON in aqueous solution and can be effective for decontamination of grain. This study reports the efficacy of gaseous ozone treatments in reducing DON, DON-3-Glc, bacteria, fungi and yeasts in naturally contaminated durum wheat. A prototype was used to dispense ozone continuously and homogeneously at different concentrations and exposure time, in 2 kg aliquots of durum wheat. The optimal conditions, which do not affect chemical and rheological parameters of durum wheat, semolina and pasta, were identified (55 g O3 h-1 for 6 h). The measured mean reductions of DON and DON-3-Glc in ozonated wheat were 29 and 44%, respectively. Ozonation also produced a significant (p<0.05) reduction of total count (CFU/g) of bacteria, fungi and yeasts in wheat grains.