Molecular Characterization of Mycotoxigenic Moulds Isolated from Herbs and Spices Sold in Open Markets in Benin City, Edo State

Herbs are widely used as medicinal, edible, and health products.However contamination of these valuable products by mycotoxigenic molds poses a serious problem to human health. The aim of this study was to isolate and characterize mycotoxigenic moulds from herbs and spices using molecular technique. A total of 18 samples of herbs and spices were obtained from three markets (Uselu , New Benin and Oba) in Benin City, Edo state. All samples were serially diluted and inoculated on potato dextrose agar (PDA) using the pour plate technique. Pure cultures were obtained, and fungal isolates were identified using culture-based and molecular techniques. The presence of aflatoxin-coding gene (aflD) in selected isolates was determined using Polymerase Chain Reaction (PCR) technique. The pH of each sample was determined using an electronic pH meter (pH-98108) and the moisture contents were determined according to the method of AOAC. Fungal counts ranged from 0.06 ± 0.05x103 to 0.50 ± 0.03 x103 cfu/g. Fungi isolated in this study include Aspergillus niger , Aspergillus verrucosus, Fusarium oxysporum, Penicillium chrysogenum, Aspergillus flavus, Penicillum sp, Fusarium sp Cladosporium, Rhizopus . The most occurring fungi was Aspergillus niger (32.5%) while Aspergillus verrucosus (2.5%) was the least occurring. The mean pH values of samples ranged from 4.53±0.25 – 6.13±0.5 while the moisture content ranged from 7.04±0.01 – 12.24±0.10%. Results of the molecular characterization revealed that all Aspergillus isolates had the aflD gene. The isolation of mycotoxigenic moulds such as A.niger, A.flavus and F. oxysporum in this study, were of significant health importance. Hence, the constant usage of these contaminated food spices could lead to deleterious health effects in man.