Brief Note

Supersize My Bugs

By Carol A. Kemper, MD, FACP, Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases, Santa Clara Valley Medical Center. Carol A. Kemper, MD, FACP, does research for GSK Pharmaceuticals, Abbott Laboratories, and Merck. This article originally appeared in the February issue of Infectious Disease Alert. At that time it was reviewed by Connie Price, MD, Assistant Professor, University of Colorado School of Medicine; she reports no financial relationship to this field of study.

Source: White AS, et al. Beverages obtained from soda fountain machines in the U.S. contain microorganisms, including coliform bacteria. IntJ Food Microbiol 2010;137:61-66.

This engaging epidemiologic survey assessed microbial contamination of soda-fountain drinks, dispensed from nine different fountain machines, relative to current U.S. drinking water standards. Ninety drinks, including diet soda, regular soda, water, and ice were cultured. A follow-up survey examined the concentration of bacteria and other organisms found in an additional 27 drinks collected either in the morning or the afternoon. The beverages were self-dispensed or dispensed by a server.

Nearly half (48%) of the beverages contained coliforms, and one in 10 had more than 500 bacterial colony-forming units per mL. The most common pathogen identified was Chryseobacterium meningosepticum, found in 17% of the beverages, followed by Escherichia coli in 11%. Other microbes isolated included Klebsiella, Staphylococcus, Serratia, Stenotrophomonas, and Candida spp. Ice alone did not exceed current U.S. drinking water standards. No difference was observed in rates of bacterial contamination between self-dispensed drinks and those dispensed by a server, suggesting the machines are the source of the contamination.