Fusarium moniliforme Sheldon occurs worldwide on corn intended for human and animal consumption. A closely related species Fusarium proliferatum also occurs frequently on corn. Yellow dent corn, white dent corn, white and yellow popcorn and sweetcorn may be contaminated. Both organisms are capable of producing a group of toxins known as fumonisins, of which Fumonisin B1 (FB1), Fumonisin B2 (FB2) and Fumonisin B3 (FB3) are most common. Fumonisins have been found in corn and corn-based foods worldwide. Fumonisins may be found in sound whole kernel corn at levels at or below 1.0 μg/g. By contrast animal disease problems begin to occur at fumonisin levels above 5.0 to 10.0 μg/g. Corn-based food products that have the most frequent and highest fumonisin levels, besides whole kernels, are corn meal and corn grits. In the United States, corn meal has been found contaminated with Fumonisin B1 at levels from 0.5 to 2.05 μg/g, and grits from 0.14 to 0.27 μg/g. Corn flakes, corn pops, corn chips and tortilla chips have been found negative for fumonisins. Popcorn, sweetcorn and hominy corn have been found contaminated with sporadic, low levels (0.01 to 0.08 μg/g) of fumonisins. The effects of processing on fumonisins in corn are still largely unknown. Heating may cause a loss of fumonisins in corn, but it may be a loss of detectability rather than degradation.