Genotoxic evaluation of ammonium inactivated aflatoxin B₁ in mice fed with contaminated corn

Aflatoxin B₁ (AFB₁) is a major contaminant in different agricultural products including maize. In an attempt to reduce this problem and the hazards to human health, an AFB₁ inactivating system with ammonia has been developed. In this work we evaluated the efficiency of the system in mice using micronucleus (MN) and sister chromatid exchange (SCE) analysis. Four groups of animals were fed during 8 weeks with a special diet mainly composed of maize: (1) uncontaminated; (2) uncontaminated/ inactivated; (3) contaminated/inactivated; and (4) contaminated. We evaluated MN at weekly intervals in peripheral blood, and in weeks 4 and 8 SCE frequencies were quantified in bone marrow cells. The results showed that animals fed with AFB₁ contaminated/inactivated maize had a 45% lower level of induced cytogenetic damage than those animals fed with AFB₁ contaminated, but not inactivated maize. A residual amount of AFB₁ after the inactivating treatment and the reconversion back to AFB₁ in the organism may account for the remaining increased levels of SCE and MN.