Brief Report

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.

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 bacterial colony counts > 500 colony-forming units per mL. The most common pathogen identified was Chryseobacterium meningosepticum, found in 17% of the beverages, followed by E. coli in 11%. Other microbes isolated included Klebsiella, Staphylococcus, Serratia, Stenotrophomonas, and Candida spp. Ice alone did not exceed 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.