FB1FB2

FB1 and FB2, collectively referred to as fumonisins B1 and B2, are mycotoxins produced by Fusarium species, most notably Fusarium verticillioides and Fusarium proliferatum. They frequently contaminate maize and maize-based foods and feeds, especially in warm, humid regions. Because they often occur together, surveys and regulation commonly refer to the sum of FB1 and FB2.

Chemically, FB1 and FB2 are sphingoid-like toxins. They share a common long-chain backbone and differ in specific ester groups; FB1 contains two tricarballylic acid esters. Their structural similarity to natural sphingolipids underlies their biological activity, which centers on disruption of sphingolipid metabolism through inhibition of ceramide synthase.

Toxicology and health effects: In animals, fumonisins can cause liver and kidney toxicity, with species-specific manifestations such as equine leukoencephalomalacia and porcine pulmonary edema. In humans, fumonisin exposure is associated with potential health risks, including possible links to esophageal cancer and effects on the immune and developmental systems. The International Agency for Research on Cancer has classified fumonisin B1 as possibly carcinogenic to humans (Group 2B). The severity of effects depends on exposure level, duration, and co-exposure to other contaminants.

Exposure and regulation: Humans and animals primarily encounter fumonisins through contaminated maize products. Regulatory limits for fumonisins vary by country and often address the sum of FB1 and FB2 in cereals and maize-based foods. Monitoring relies on analytical methods such as LC-MS/MS and immunoassays.

Prevention and processing: Good agricultural and storage practices reduce Fusarium growth. Processing steps like cleaning, sorting, and nixtamalization can lower fumonisin levels. Breeding for resistant maize varieties and adherence to good manufacturing practices also help minimize risk.

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