Aflatoxin Destruction in Corn Using Sodium Bisulfite, Sodium Hydroxide and Aqueous Ammonia

Naturally contaminated yellow dent corn containing 235 ppb of aflatoxin B₁ and B₂ was adjusted to a moisture content of 20% and then treated for 24 h at ambient temperature with NaHS0₃, NaOH or aqueous NH₃ at 0.5%, 1.0%, or 2.0% concentrations. All treatments were effective in reducing aflatoxin B₁ and B₂ levels. Sodium bisulfite was more effective in destroying aflatoxins than were NaOH or aqueous NH₃ at 0.5% and 1.0% concentrations, while NaOH and aqueous NH₃ were more effective than bisulfite at 2.0% concentration. Subjecting yellow corn samples to either NaHSO₃, NaOH or aqueous NH₃ at 2.0% concentrations reduced aflatoxin B₁ and B₂ levels to below the FDA guideline of 20 ppb total aflatoxin. Sodium bisulfite was also effective in reducing the levels of aflatoxins in a white dent corn sample containing 81 ppb of aflatoxin B₁ and 12 ppb of aflatoxin B₂. Results suggest that NaHSO₃, NaOH or aqueous NH₃ can be used to effectively destroy aflatoxins in corn and possibly other agricultural commodities.