Aflatoxigenic strains of Aspergillus section Flavi isolated from marketed peanuts (Arachis hypogaea) in Algiers (Algeria)

Abstract

The present study reports on the natural mycobiota occurring in Chinese peanuts marketed in Algiers, paying special attention to the incidence of Aspergillus section Flavi species that are potential producers of aflatoxins. The mean value counts of fungi ranged from 155 to 577 CFU/g dry matter (DM) and the predominant fungi were different species of the genus Penicillium (83.81–93.85 %) and Aspergillus belonging to section Flavi (2.73–73.96 %). Results indicated that 82 isolates (100 %) were aflatoxigenic. The Aspergillus section Flavi strains revealed that 65 isolates (79.27 %) were highly aflatoxigenic, producing four kinds of aflatoxins [AFB1 (0.846–3.330 μg/g), AFB2 (0.005–0.007 μg/g), AFG1 (0.008–1.595 μg/g), and AFG2 (0.005–0.010 μg/g)], whereas 17 isolates (20.73 %) synthetized low levels of one or two aflatoxins (AFB1 and AFG2). Aflatoxin production was also screened on Coconut Agar Medium (CAM), and the results were consistent with the HPLC analysis. Based on the combination of mycotoxins produced, five Aspergillus section Flavi chemotypes were established. Sclerotia production expressed a correlation to aflatoxigenicity. The total aflatoxins were detected in four analyzed samples at levels ranging from 0.71 to 25.50 μg/kg. Furthermore, the amplicons corresponding to the ITS1-5.8 S-ITS2 rDNA of six representative strains showed that four strains belonged to Aspergillus flavus, one to A. minisclerotigenes, and one to A. caelatus. The results obtained indicate that there is a possible risk factor posed by aflatoxins contamination of peanuts marketed in Algiers.