TECHINICAL NOTE A preliminary bacterial study of Egyptian paper money FARIDA M. S. EL-DIN EL-DARS & WAEL M. H. HASSAN Chemistry Department, Faculty of Science, Helwan University, Ain Helwan, Cairo, Egypt Abstract The objective of this study was to investigate the extent of contamination of some of the most used paper denominations of the Egyptian currency (25 PT). Sixty-nine bills in circulation were collected from November 2003 through January 2004. A swab from each bill was cultured on nutrient agar and incubated at 378C for 48 h. Results showed that over 65% of these bills had a bacterial count above 5.0 cm 2 . A preliminary identification of organisms present on these paper notes was done using selected Petri dishes with well-defined colonies. Keywords: Egyptian paper money, bacterial contamination, Staphylococcus aureus, Staphylococcus albus, Klebsiella pneumoniae Introduction Paper currency is exchanged for goods and services worldwide (Pope et al. 2002). Even though these bills are made of a rugged mix of 75% cotton and 25% linen (Gadsby 1998), they offer more surface area for bacteria and microorganisms to reside on both sides. Coins, on the other hand, offer less residing time for microorganisms and bacteria on their faces (estimated at 9 – 11 days) (Bonifazi 2002; Craig 2002). Moreover, the presence of an appreciable amount of Cu coined metal alloys seems to be the limiting factor for bacterial survival on coins in general (Bonifazi 2002). On the other hand, the older the paper notes become, the more space they offer for germs and microorganisms (pathogenic and non- pathogenic) to accumulate (Brown 2003). Accordingly, this increases the amount of bacteria circulated and distributed among its handlers. In a recent study, 94% of 68 US one-dollar bills were found to be contaminated with potentially pathogenic or pathogenic microorganisms (Pope et al. 2002). Studies on Chinese currency (China) after the outbreak of SARS in Asia found some banknotes carried over one hundred thousand types of bacteria and 9500 E. coli-like organisms (Brown 2003). Newer banknotes from the Hong Kong area carried a lower count than in those in China; however, banknotes from Northern Korea were almost bacteria free. Older notes studied in China, Hong Kong, India, Pakistan, Cambodia and the Philippines carried overwhelming amount of bacteria on both surfaces. Some of these organisms found were considered potentially Correspondence: Farida M. S. El-Din El-Dars, 3 Kabool Street, Madinet Nasr, Cairo 11371, Egypt. E-mail: fkeldars@hotmail.com or fkeldars@aucegypt.edu International Journal of Environmental Health Research June 2005; 15(3): 235 – 239 ISSN 0960-3123 print/ISSN 1369-1619 online ª 2005 Taylor & Francis Group Ltd DOI: 10.1080/09603120500105976