Distribution of moniliformin in industrial maize milling and flaking process

Moniliformin (MON) is a widespread emerging mycotoxin often occurring in maize at significant levels. Few published studies investigated MON redistribution in maize-derived products for human consumption; to better understand this issue, 5 maize lots with different levels of MON contamination were processed following an industrial milling process to evaluate the redistribution of the mycotoxin in final products (grits), by-products destined to feed (bran and flour) and cleaning waste. MON was quantified by LC-MS/MS after the purification step through the SPE column; moreover, a confirmatory method based on MON derivatization with 1,2-diamino-4,5-dichlorobenzene was developed. Relevant MON reduction was obtained after sieve cleaning, scourer process, and optical sorting, achieving a decrement of the concentration level close to 70%. The following other milling procedures showed a limited reduction from cleaned maize to small and large grits; considering the entire industrial process, the reduction percentage of MON contamination in the final products was 80.9 ± 9.3% and 81.0 ± 6.7% for small and large grits, respectively. The flaking process showed a very limited reduction of MON, close to 10%. Considering the widespread of MON occurrence in maize, the study highlights the importance of cleaning steps to achieve a low risk of exposure for the consumer.