Are aflatoxins and fumonisins commonly found in contaminated stored foods?

Agricultural commodities stored under suboptimal conditions are highly susceptible to contamination by mycotoxins, specifically aflatoxins and fumonisins. These secondary metabolites are prevalent globally, often co-occurring in staple dietary sources and presenting severe public health risks.

Environmental drivers of contamination

• Fungal synthesis: Aflatoxins are primarily produced by Aspergillus flavus and Aspergillus parasiticus, while fumonisins are synthesized by Fusarium species, predominantly Fusarium verticillioides.
• Atmospheric catalysts: Fungal proliferation and subsequent toxin biosynthesis are heavily driven by high moisture levels (exceeding 16%) and warm, tropical storage temperatures.
• Target commodities: Aflatoxins frequently contaminate maize (corn), groundnuts (peanuts), tree nuts, and spices. Fumonisins are dominantly found in maize and maize-based products, leading to high rates of dietary co-exposure.

Pathophysiological mechanisms and health risks

• Hepatocellular carcinoma: Chronic dietary exposure to aflatoxins, particularly aflatoxin B1 (AFB1), is highly carcinogenic to liver tissue, serving as a primary driver of hepatocellular carcinoma.
• Esophageal cancer: Fumonisin B1 (FB1) exposure is strongly linked to the development of esophageal cancer, particularly in regions where maize serves as the primary dietary staple.
• Regulatory limits: To mitigate these severe oncogenic risks, international food safety bodies enforce strict thresholds, restricting aflatoxins to low parts-per-billion (ppb) levels and fumonisins to parts-per-million (ppm) ranges. Control measures rely on post-harvest drying, hermetic storage, and crop sorting.

Bottom line

• Stored agricultural commodities like corn, nuts, and spices are highly susceptible to contamination by aflatoxins and fumonisins under warm, moist conditions, posing severe health risks including liver and esophageal cancers.