Microbial Contamination of Currency Notes in Circulation in Onitsha Main Market, Anambra State

Banknotes pass through thousands of hands daily in high-volume Nigerian markets, accumulating microbial contamination that may constitute a public health risk, yet studies on Nigerian currency contamination are limited. This study assesses the microbial contamination of naira notes in active circulation in Onitsha Main Market, Anambra State, South East Nigeria. A total of 80 currency notes in denominations of 10, 50, 100, 200, and 500 naira were collected from food vendors, drug sellers, and general traders. Swab samples from each note were cultured on nutrient agar, blood agar, Sabouraud dextrose agar, and MacConkey agar. Total bacterial count, total fungal count, and pathogen presence were determined. Total bacterial counts ranged from 1.8 x 103 to 9.2 x 106 cfu/note. Pathogenic organisms isolated included Staphylococcus aureus (62 percent of notes), Escherichia coli (38 percent), Klebsiella species (22 percent), and Salmonella species (8 percent). Higher denomination notes did not consistently show lower contamination. Food vendor notes showed higher contamination than general trader notes. Aspergillus and Candida species were recovered from 48 percent of notes. MRSA was confirmed in 18 percent of Staphylococcus aureus isolates. The study recommends consumer hand hygiene promotion, particularly after currency handling, and public health awareness campaigns about banknote contamination risks in high-volume markets. Keywords: currency contamination, banknotes, Staphylococcus aureus, Onitsha, public health