ABSTRACT

Cyperus esculentus (Tigernut) grows as a perennial grass-like plant in the old world and produces tasty tubers that resemble nuts and are referred to as “earth almonds”. The aim of this study was to analyze the fungal load of environmentally exposed tigernut (Cyperus esculentus) obtained from different markets in Benin City, Edo State, Nigeria. Samples of tigernut were obtained from three different market locations in Nigeria. The samples were taken to the Laboratory for further analyses. Serial dilutions were made and required volume (0.1ml) of test samples were dispensed separately into sterile Petri dishes and spread plated with PDA for growth and enumeration of colonies. A total of four fungi isolates were identified. Fusarium sp., Candida sp. and Aspergillus terreus were identified culturally and with the aid of a microscope while Aspergillus niger OR225640 was identified through molecular analysis. The heterotrophic fungal counts for each market ranged from 1.0±0.00×10³ - 9.0±0.54×10³ cfu/ml (Ekosodin market), 6.0±2.06×10³ - 8.0±1.36×10³cfu/ml (Oba market) and 5.0±0.35×10³ - 8.0±1.96×10³. Statistical analysis using one way analysis of variance revealed that the total fungal load of tigernut tubers from Ekosodin market was significantly different (p<0.05) from the samples obtained from Oba market and New Benin market. The frequency of occurrence for the fungi isolated were 7.7 for Fusarium sp., 17.5 for Candida sp. and 6 for Aspergillus terreus in Oba market; 8.6 for Fusarium sp., 4 for Candida sp and 1 for Aspergillus niger in Ekosodin market; 6.7 for Fusarium sp., 8.3 for Candida sp. and 4.5 for Aspergillus terreus in New Benin market. From the findings in this study, it is recommended that contamination of tigernut tubers and tigernut-derived products should be reduced by removing any foreign items and washing thoroughly with potable water before sale to the public and consumption.