Detection of ochratoxin produced by A. ochraceus in feedstuffs and its control by γ radiation

γ-Irradiation has been proposed as a means of food preservation and as an appropriate process for decontamination of toxigenic moulds in animal feeds prior to their production of mycotoxins. The investigation of 295 samples of livestock feedstuffs revealed that Aspergillus ochraceus occurs with high incidence in straw samples (90%), in 40–60% of hay, cotton-seed cake, and rice samples and in 10–30% of wheat, yellow corn, barley, broiler's concentrates, kidney beans and tibn samples. Ochratoxin A was detected in 98 of 295 samples of stored feedstuffs at levels ranging from 700 to 8000 ppb. At a radiation dose 4 kGy, the growth of A. ochraceus and the subsequent ochratoxin production in poultry feed concentrates were completely inhibited. A dose of 15 or 20 kGy was sufficient for complete destruction of ochratoxin in yellow corn and soyabean. A dose of 20 kGy, however, controlled the occurrence of ochratoxin in poultry layer's concentrates, broiler's concentrates and cotton-seed cake by only 40, 47 and 36%, respectively.