Fumonisins B1 and B2 are the main members of a family of mycotoxins produced by species of the Gibberella fujikuroi complex. However, Fusarium verticillioides is the most relevant fumonisin producer in cereals grains in subtropical and tropical climate areas. The occurrence of fumonisins in maize, wheat, barley and sorghum and by-products (grits, flakes, snacks, flour, etc.) is a widespread problem worldwide. However, very little is known about the occurrence and conditions for production of fumonisins in rice. The present work shows the results of a comparative study of various clean-up and derivatization procedures for analysis of fumonisins in rice contaminated with F. verticillioides. For clean-up, three solid-phase extraction procedures were assayed (C18 and SAX cartridges, and a combination of both). Two reagents (o-phthaldialdehyde and 4-fluoro-7-nitro-benzofurazan) were studied for formation of fluorescent derivatives. The separation was carried out by LC using a fluorescence detector. The best procedure for analysis of fumonisins in rice involved clean-up with C18 cartridge and derivatization with o-phthaldialdehyde. The limit of detection was 0.010 mg/kg for both toxins. The recovery rates for FB1 and FB2 in rice varied from 94.6% to 103.6% and from 96.3% to 101.9%, respectively. Fumonisin production was highest at 20 ºC than 37 ºC and production was not detected at a_w 0.96.

Acknowledgements. The authors acknowledge financial support from FEDER and Spanish Government (Project  AGL2010-22182-C04-01-03/ALI), Generalitat Valenciana (ACOMP/2013/176) and Universitat Jaume I, Project P1.1B2012-36.