Analytical issue related to fumonisins: A matter of sample comminution?

The aim of the present work was to evaluate the effect of sample particle size on fumonisins recovery during the extraction step. Four maize samples were ground and the resulted flours were separated in six different fractions according to their particle size (1000-250 μm). Fumonisin B1 and B2 were quantified on each fraction, as well as on the unfractionated sample by HPLC-MS/MS. Furthermore, the proximate analysis was carried out to exclude the influence of macro-constituent on the mycotoxins distribution. Although the six maize fractions were found to be characterized by the same macro-constituent composition, a significant increase (p < 0.000) of fumonisins content was observed in all the analysed samples. Extraction yields up to five times higher were found in the finer flours. From the above, it is clear that the sample particle size has a significant impact on the fumonisins recovery. The outcomes suggest that sample granulometry should be standardized for ensuring accuracy and reliability of the analysis results. Overall, the results of this study, although still preliminary, may offer a reliable analytical solution to finally address the “hidden fumonisin issue”