Isolation of Filamentous Fungi Species Contaminating Some Nigerian Food Commodities

Samples of maize, rice, cocoa and cocoa-based powder beverage) collected from different stores and markets in south-western Nigeria were screened for filamentous fungi contamination using conventional and molecular methods. Samples were cultured aseptically on potato dextrose agar (PDA), ohio agricultural experimental agar (OEASA), Malt Extract Agar (MEA) and Czapek Yeast Agar (CYA) prior to fungi isolation. Conventional methods comprising of macroscopic and microscopic evaluation of isolated fungi species were implemented in the analysis for identification of fungi species. Molecular method of identification involved DNA extraction, Polymerase chain Reaction (PCR) using ITS-1/ITS-4 primer pair and nucleotide sequencing. Results obtained indicated a range of filamentous fungi genus including Aspergillus, Penicillium, Fusarium, Alternaria, Cladosporium and Rhizopus contaminating the food commodities with Aspergillus and Penicillium species dominating most of the samples. High incidences were recorded for Aspergillus flavus, Aspergillus niger and Aspergillus fumigatus in most of the samples screened. The occurrence of these filamentous fungal species pose a reason for concern as most of these fungal species are known producers of toxic substances. This study was carried out to contribute to mycological screening of different Nigerian food commodities for a variety of filamentous fungi species.