Simultaneous Occurrence of Aflatoxin and Ochratoxin A in Rice from Kaduna State, Nigeria

Abstract

Eighty six samples of field, stored and marketed rice (Oryza sativa) collected from the traditional rice growing areas of Kaduna state, were analyzed for aflatoxins (AFs) and ochratoxin A (OTA) by high- performance liquid chromatography (HPLC). Aflatoxins were detected in 74.4% of the samples, AFB1 was found at concentrations between 4-292μg/kg and AFB2 between 0.4-27.2μg/kg. OTA was found at concentrations between 0.2 μg/kg and 35.6μg/kg but at higher prevalence than aflatoxins. Co- contamination with AF and OTA was common; thirty seven (37) of the rice samples contained both aflatoxins and ochratoxin A. The AFB1 and OTA levels in 100% and 58% of the rice samples were regarded as unsafe based on Nigerian and European Union maximum permissible levels of 2μg/kg and 5μg/kg respectively. The presence of these toxins at unacceptable concentrations and their multi- occurrences in the rice samples which might exert either additive or synergistic toxic effects in human beings raise concern with respect to public health.