Determination and characterization of the antimicrobial activity of the fermented tea Kombucha

Abstract

Early reports on Kombucha, a traditional fermented tea beverage, suggested that it has antimicrobial activity against a spectrum of organisms, and that concentrates of unfermented tea components also have anti m icrobial properties. Therefore, the focus of this study was to determine and characterize Kombucha's antimicrobial activity using an absorbent disc method. Antimicrobial activity was observed in the fermented samples containing 33 g/L total acid (7 g/L acetic acid) against the tested Gram-positive and Gram-negative organisms (Agrobacterium tumefaciens, Bacillus cereus, Salmonella choleraesuis serotype typhimurium, Staphylococcus aureus, and Escherichia coli. Candida albicans was not inhibited by Kombucha. The contribution of tea itself to the antimicrobial activity of Kombucha proved to be significant in the tested organisms, even at the highest levels tested, 70g/L dry tea. As a result, the antimicrobial activity of Kombucha was attributed to its acetic acid content. ©1998 Academic Press.