First survey on the presence of ochratoxin A and fungi in raw cereals and peanut available in the Republic of Niger

Abstract

Eighty one (81) samples of cereals (rice, maize, sorghum, millet) and peanut purchased from six local markets of Niamey city (Republic of Niger) were analyzed for the presence of fungi and ochratoxin A (OTA). Samples were microbiologically analyzed for determination of fungi. For OTA analysis, samples were extracted with methanol with an Ultra-Turrax homogenizer. OTA was then identified and quantified by using liquid chromatography (LC) with fluorescence detection. The confirmation of OTA identity in positive samples was confirmed by methyl ester derivatization.Analytical results showed that samples were contaminated with a large number of fungi, the most important genus are Aspergillus spp. (63%) followed by Fusarium spp. (9.7%) and Penicillium spp. (3.3%). Mycotoxin analysis showed that OTA was present in 85.7, 9 and 2.6% of peanut, rice and maize, respectively. The frequency of contamination of total analyzed samples was 9.8%. Levels of OTA in positive samples ranged between 0.1 and 4.9 ng/g. The average contamination of cereals samples with OTA was 3.7 ng/g. The high level value of OTA (4.9 ng/g) was found in a peanut sample commercialized in “Wadata market” of Niamey city. The present paper is the first ever drafted on the natural occurrence of OTA and fungi in cereals and peanut consumed in Republic of Niger.