Effect of thermal processing on the stability of fumonisins

Fumonisins, a group of mycotoxins produced by Fusarium moniliforme in corn, have been implicated in several animal and human diseases. F. moniliforme and the fumonisins are an area of incresing concern for corn producers and consumers. Consequently, there is interest in reducing human and animal exposure to these fungal toxins. Studies of the effects of biological, chemical, and physical treatments on the reduction of fumonisin levels in food have shown variable results. Work was conducted at the U.S. Food and Drug Administration, National Center for Food Safety and Technology, to determine the effects of thermal processing on fumonisins B1 (FB1) and B2 (FB2) in an aqueous buffer. Parameters that were studied included processing time (0-60 min), processing temperature (100-235 degrees C), and buffer pH (4, 7, and 10). The rate and extent of fumonisin decomposition increased with processing temperature. Less than 27% of FB1 and less than 20% of FB2 were lost when processing temperatures were less than or equal to 125 degrees C for 60 min. After 60 min at 150 degrees C, losses of FB1 and FB2 were 80-90% at pH 4, 18-30% at pH 7, and 40-52% at pH 10. At temperatures greater than or equal to 175 degrees C, more than 80% of FB1 and FB2 was lost after 60 min. These results indicate that foods reaching temperatures greater than 150 degrees C during processing may have lower fumonisin levels. More work is needed to quantitate the effects of different processing operations (baking, extrusion, frying) on the fumonisin content of corn-based foods.