fumonisins

Fumonisins are a group of mycotoxins produced by cereal-associated Fusarium species, chiefly Fusarium verticillioides and Fusarium proliferatum. The best known member is fumonisin B1 (FB1); FB2 and FB3 also occur. These toxins are commonly found in maize and maize-based foods, and can contaminate sorghum, barley, and other grains under warm, humid conditions.

Fumonisins occur worldwide wherever maize is grown; contamination can occur in the field or during postharvest storage. Humans and animals are exposed mainly via ingestion of contaminated maize and products such as cereals, tortillas, and other staples. Because maize is a dominant staple in many regions, fumonisin exposure can be substantial; many countries regulate maximum allowable levels in foods.

The core mechanism is inhibition of ceramide synthase, a key enzyme in sphingolipid metabolism, which disrupts cell membranes and signaling. In animals, fumonisins are hepatotoxic and nephrotoxic and can cause neurotoxic effects. In humans, epidemiological data have explored links to esophageal cancer and neural tube defects in offspring in certain regions, but evidence for causality is limited.

Fumonisins are relatively heat-stable and are not fully destroyed by cooking. They can be reduced by processing and purification steps, but complete elimination is not guaranteed. Prevention focuses on good agricultural and storage practices, sorting, cleaning, and monitoring of maize for mycotoxins; risk assessment informs regulatory limits. Analytical methods such as LC-MS/MS and HPLC are used to quantify FB1, FB2, and FB3 in foods.