Fungal flora of Nigerian currency notes in circulation in Benin City, Nigeria.

A mycological survey of Nigerian currency (naira) notes in circulation in Benin City was undertaken to determine the fungal species present, so as to bring to light the health implications of their presence. A total of 84 naira notes comprising 20, 50, 100, 200 and 500 naira denominations were obtained randomly from a bank, commuter bus, food canteen, and open market. Four-day old Potato Dextrose Agar cultures of diluted water diffusate of the currency notes were examined under the microscope and fungi were isolated and identified. The isolated fungi and their frequencies of isolation were A. flavus (90.5), A. fumigatus (42.9), A. terreus (57.1), A. flavipes (26.2) A. niger (59.5), Candida albicans (92.3), Rhizopus sp (2.7), Penicillium sp (4.0), Fusarium sp (12.8), and Saccharomyces cerevisae (16.1%). The frequencies of fungi isolated from the various denominations varied significantly at 0.05 probability. While the 50 naira denomination had the highest colony count (mean of means = 41 colonies/ml) the 500 naira had the lowest colony count (mean of means =8.3 colonies/ml). The high occurrence of fungi in the currency notes is of public health concern.