Fumonisins are a group of structurally related mycotoxins produced primarily by the fungus Fusarium moniliforme and Fusarium proliferatum. Fumonisin B1 (FB1) and fumonisin B2 (FB2) are the most important of this group of compounds, and have been frequently found at global level in naturally contaminated maize and maize products. The concern for these toxins has been growing in the scientific community and also among administrators, farmers and animal producers because they have been shown to cause diseases in horses, pigs and chickens and hepatocarcinomas in rats and have been statistically associated with an increased risk of oesophageal cancer in humans consuming contaminated maize.
The objective of this project was to improve the quality of fumonisins (FB1 and FB2) analysis in maize to allow European food and feed control laboratories to undertake regular monitoring of maize products as required to assess risks and to protect consumer and animals.
The intercomparison study generated data (after correction for recoveries) with very high precision (mean +/- 1SD of 2.29 +/- 0.27 ug/g for FB1 and 1.25 +/- 0.17 ug/g for FB2; within-laboratory (RSDr) and between-laboratory (RSDR) relative standard deviation of 10% and 11% for FB1 and 11% and 13% for FB2, respectively). However, most participants obtained low recoveries (average, 70% for FB1 and 69% for FB2), which were considerably affected by the extraction mode. Average recoveries for laboratories using blending were 62% and 60%, whereas for laboratories using shaking were 85% and 86% for FB1 and FB2, respectively. In addition, the following factors improving recoveries were identified: consecutive extractions, extraction with higher solvent to maize ratio, and SAX clean-up instead C18 clean-up. No substantial inhomogeneity at the 95% confidence and no instability of the maize materials was detected. A satisfactory sterilization of maize materials was obtained with g-irradiation at 15 kGy, although this process caused a decrease of the fumonisins content of about 20%.
The following activity has been performed: (i) preparation of a calibrant solution containing fumonisins B1 and B2 and two maize materials (a "blank" and a material contaminated with fumonisins B1 and B2); (ii) assessment of the optimal conditions for sterilization of the maize materials by g-irradiation; (iii) homogeneity and stability studies of the maize materials and calibrant solution; (iv) intercomparison study to test different analytical procedures (i.e. their extraction, clean-up and end-determination) for fumonisin determination in contaminated and "blank" maize materials. Twenty-four laboratories took part in the intercomparison study. Analyses were performed by each participant on "blank", contaminated and spiked materials; recovery factors were also established.