Molecular Characterization of Moulds Isolated from Stored Food Products in Imo State, Nigeria

Cereals and legumes are important food crops and provide cheap sources of energy and protein, and therefore, are good substitutes or supplements to major staples foods and help meet the needs of Africa's teeming population. Five food products (rice, maize wheat, groundnut and beans) stored for 2 4 months in different packaging materials were assessed for the presence of mycotoxin producing moulds. These samples were randomly selected from different markets. Standard microbiological and molecular methods were used in the isolation and identification of moulds. The frequently occurring moulds species identified molecularly were Aspergillus flavus, Aspergillus tamarii, Aspergillus niger, Aspergillus brunneoviolaceus, and Penicillium chrysogenum. The dominant mould species were Aspergillus flavus (46%) followed by Aspergillus tamari (23%), Aspergillus niger (18%), and Penicillium chrysogenum (9%) while the least was (4%) Aspergillus brunneoviolaceus. The Phylogenic tree was constructed by using the geneious software version 4.0. (By Neighbor-joining (N-J) method based on the 18s rDNA sequence.) The 18S rDNA sequence analysed showed that strains were most closely affiliated with members of their genus. The occurrence of high contamination level of Aspergillus species indicates the possible production of aflatoxin in stored food products. There is a strong need to devise good storage condition for stored food products to avoid mycotoxigenic moulds contamination.