Reduction of Fumonisin Toxicity by Extrusion and Nixtamalization (Alkaline Cooking)

Fumonisins are mycotoxins found in corn. They are toxic to animals and cause cancer in rodents and neural tube defects in LM/Bc mice. Reducing their concentrations in corn-based foods is therefore desirable. Chemical analysis or in vitro bioassays of food extracts might not detect toxic fumonisin reaction products that are unknown or unextractable from food matrices, thus potentially underestimating in vivo toxicity. The effectiveness of two common cooking methods, extrusion and nixtamalization (alkaline cooking), to reduce the toxicity of fumonisin-contaminated corn grits (extrusion) and whole kernel corn (nixtamalization) was shown by means of rat feeding bioassays using fumonisin-specific kidney effects as indicators of potential toxicity. A third bioassay showed that in contrast to fumonisin B₁ (FB₁), hydrolyzed fumonisin B₁ (HFB₁; formed from FB₁ during nixtamalization) did not cause neural tube defects in LM/Bc mice. The findings indicate that extrusion and nixtamalization reduce the potential toxicity of FB₁-contaminated corn.