Mycotoxin contamination of animal feedingstuff: detoxification by gamma irradiation and reduction of aflatoxins and ochratoxin A concentrations

Mycotoxins are fungal secondary metabolites identified in many agricultural products screened for toxigenic moulds. Mycotoxins have been reported to be carcinogenic, teratogenic, tremorogenic, haemorrhagic and dermatitic to a wide range of organisms. With the increasing stringent regulations for the mycotoxins, imposed by the importing countries such as the EU, many cereals that are not safe for human consumption, are used in formulations intended for animal feed. Gamma rays are reported in the scientific literature to destroy ochratoxin A and aflatoxin in food crops and feed. The present study provides preliminary data for establishing the effect of dose of gamma irradiation, ranging from 0 to 15 kGy, on aflatoxins and ochratoxin A reduction in commercial animal feed. The mycotoxin levels were determined by means of immunoaffinity clean-up (IAC) and HPLC with fluorescence detection (HPLC-FLD). The maximum reduction was found at 15 kGy and it was 23.9%, 18.2%, 11.0%, 21.1% and 13.6% for ochratoxin A, aflatoxin B1, aflatoxin B2, aflatoxin G1 and aflatoxin G2, respectively. Results showed that the gamma rays even at 15 kGy were not effective in the complete destruction of ochratoxin A and aflatoxins in the tested feed.