Transformation patterns of masked fusarium mycotoxins during barley malting: Mechanistic evidence and multimodal detection in industrial products

Malt, a key food industry ingredient, faces safety risks from Fusarium mycotoxins and masked derivatives. While malt's agricultural role is clear, biotransformation pathways of masked mycotoxins during barley malting remain poorly understood. This study assesses mycotoxin contamination in commercial malt and links fungal communities to mycotoxin metabolism. Deoxynivalenol dominated, detected in 55% beer and 70% malt samples, with low adult exposure risk. Using ultra performance liquid chromatography-tandem mass spectrometry and internal transcribed spacer sequencing, natural malting showed biphasic dynamics: toxigenic fungi and masked mycotoxins first declined, then resurged. Artificial trials revealed deoxynivalenol converted to deoxynivalenol-3-glucoside with 30% efficiency (based on deoxynivalenol loss), while zearalenone derivatives fluctuated. This study provides the first systematic evidence demonstrating the conversion of deoxynivalenol to deoxynivalenol-3-glucoside during the malting process of barley, offering actionable insights for the development of tailored mycotoxin mitigation strategies in industrial malt production and beer brewing.