Fumonisin B3

This study was designed to investigate the fate of fumonisins in flaking corn grits during twin-screw extrusion by measuring fumonisin B₁ (FB₁) and its analogs with a mass balance approach. Food grade corn grits and 2 batches of grits contaminated with FB₁ at 10 and 50 μg/g by Fusarium verticillioides M-2552 were processed with or without glucose supplementation (10%, w/w) with a twin-screw extruder. Extrusion reduced FB₁ in contaminated grits by 64% to 72% without glucose and 89% to 94% with added glucose. In addition, extrusion alone resulted in 26% to 73% reduction in the levels of fumonisin B₂ and fumonisin B₃, while levels of both mycotoxins were reduced by >89% in extruded corn grits containing 10% glucose. Mass balance analysis showed that 38% to 46% of the FB₁ species detected in corn extruded with glucose was N-(deoxy-D-fructos-1-yl)-FB₁, while 23% to 37% of FB₁ species detected in extruded corn grits with and without added glucose was bound to the matrix. It was also found that the hydrolyzed form of FB₁ was a minor species in extruded corn grits with or without added glucose, representing Practical application:Twin-screw extrusion is widely used in food industry for its versatility. This technology may reduce the level of fumonisins in corn particularly with added glucose.

The Food Safety Commission of Japan (FSCJ) conducted a self-tasking assessment of mycotoxins, fumonisin B1 (FB1 CAS No. 116355-83-0), fumonisin B2 (FB2 CAS No. 116355-84-1), and fumonisin B3 (FB3 CAS No. 136379-59-4). Hepatotoxicity and/or nephrotoxicity were commonly observed in experimental animals given orally purified FB1, and the sex-related differences were observed in rats and mice. Species differences were also identified: Increased incidences of liver tumors in female mice and of kidney tumors in male rats were observed in chronic toxicity/carcinogenicity studies. Fumonisins did not show appreciable genotoxicity both thein vivoandin vitrotests. FSCJ judged fumonisins as non-genotoxic carcinogens from the results of various toxicological studies on fumonisins, and thus specified a tolerable daily intake (TDI) of 2 μg/mg bw/day for fumonisins (FB1, FB2 and FB3, alone or by combination), after applying an uncertainty factor of 100 to the lowest no-observed-adverse-effect level (NOAEL) of 0.21 mg/kg bw/day in subacute toxicity study in rats. The estimated exposure levels of fumonisins among high consumers such as toddlers are still below the TDI. Therefore, FSCJ concluded that adverse effect of fumonisin on human health through food are unlikely under the current situation in Japan.

To validate an LC-MS/MS method using a strong anion exchange cartridge for simultaneous determination of fumonisin B1, B2 and B3 in corn, an inter-laboratory study was performed in 9 laboratories using one fumonisin-negative corn sample, three spiked corn samples (FB1: 100-1,000 μg/kg, FB2 and FB3: 10-100 μg/kg) and two naturally contaminated corn samples. The recoveries were in the ranges of 79.7-87.2% for FB1, 78.6-103.2% for FB2 and 80.1-92.8% for FB3. The relative standard deviations for repeatability (RSDr) ranged from 3.7 to 8.0% for FB1, from 2.6 to 15.3% for FB2 and from 4.3 to 9.7% for FB3. The relative standard deviations for reproducibility (RSDR) for FB1, FB2 and FB3 were in the ranges of 6.3-10.1%, 5.9-18.7% and 9.3-16.0%, respectively. The HorRat values for all analytes ranged from 0.2 to 0.9. The difference of the trueness between the two kinds of commercially available anion exchange cartridges used in this study was not significant (p>0.05). Surveillance for fumonisins in corn grits was performed using the validated method. All of the samples were contaminated with fumonisins and the mean concentrations for FB1, FB2 and FB3 were 118.1, 37.3 and 17.9 μg/kg, respectively. These results indicated that the method for simultaneous determination of FB1, FB2 and FB3 in corn was successfully developed and validated.