NATURAL INCIDENCE AND OCCURRENCE OF MAJOR MYCOTOXINS, AFLATOXIN PRECURSORS AND ASPERGILLUS METABOLITES IN NIGERIAN DATE PALM (Phoenix dactylifera L) FRUITS

Abstract

Mycotoxins profile and Aspergillus metabolites of 108 samples of date palm fruits collected from farmers stores (48) and markets (60) from Jigawa, Kano, Sokoto and Kaduna States, Nigeria were investigated. Analysis was carried out using liquid chromatography and mass spectrometry. There was no major mycotoxin (aflatoxin B1 (AFB1), ochratoxin A (OTA), and fumonisin detected in all the tested samples. Also, sterigmatocystin (STC), a key metabolite needed in the biosynthesis of aflatoxin B1 was below the limit of detection in the samples. The incidence of Aflatoxin precursors found in the samples were versicolorin (8%), nidurufin (4%) and averufin (16%) but had comparatively low maximum concentration of 1.6, 0.03, and 0.49 µg/kg respectively. Aspergillus metabolites detected in both the marketed and stored samples included nigragillin, aspulvinone and aurasperon C with the least median concentration of 1.7 x104 μg/kg. The absence of major mycotoxins in the investigated date palm fruits might be due to cultivation of improved cultivars and the missing key metabolites needed in the biosynthesis of aflatoxin B1 and fumonisins. The toxicity associated with the Aspergillus metabolites found in the fruits deserves further investigation.