Isolation and Identification of Mycotoxigenic Fungi Associated with Dried Tomato Chips from Gusau, Zamfara State, Nigeria

Abstract

Chipping and sun drying is the most popular and traditional method of tomato preservation in major tomato producing areas in northern Nigeria. The drying is done in open and on a mat or at times on bare floor including shoulder of roads or any surface that is unhygienic. Tomato is an important vegetable crop that is consumed worldwide. It has numerous vital vitamins and other nutrients that promote health and well being of humans. Tomato has been found to be beneficial in the management of diseases such as cancer, cardiovascular and so on. The improper drying of tomato and poor storage has in many reports been found to be more suitable for pathogenic fungi to grow and produce their secondary metabolites which may be poisonous to humans. A total of fifty (50) dried tomato samples were obtained from nine (9) different markets in Gusau, Zamfara state, Nigeria and screened for the presence of fungi. Isolation and identification was done using cultural and cellular examinations. Fungi Isolation was carried out on potato dextrose agar and malt extract agar, samples were inoculated and incubated for at 5 days at 25oC. Identification of the fungi
was based on colonial morphology on the plates and microscopic observation in comparison with mycological key. Fungi isolated are mostly of Aspergillus and Penicillium genera. Aspergillus niger was found to be the highest occurring fungi with 52.3%, other fungi isolated were Penicillium oxalicum, Aspergillus flavus each accounting for 6.8% of isolated and identified fungi. Penicillium chermesium, Aspergillus parasiticus, Aspergillus fumigatus, Curvularia americana with 4.5% each and Rhodotorula glutinins, Fomitopsis meliae, Penicillium vericussum, Chaetominum, Aspergillus nidulans and Aspergillus sydowii with 2.3% each. Some of these fungi species are known to produce toxins which could be harmful to both humans and livestock.