ANTIBACTERIAL AND ANTIFUNGAL ACTIVITIES OF BLACK AND GREEN KOMBUCHA TEAS

Kombucha is widely consumed as black tea fermented for 714 days. The aim of the present study was to compare the antimicrobial activities of two kombucha beverages originating from green and black teas fermented for 21 days and to characterize the antimicrobial compounds (heat resistance and pH stability). Green and black tea infusions were fermented with a traditional kombucha culture. The resulting kombucha antibacterial/antifungal activities against some pathogenic microorganisms, including human pathogenic bacteria and clinical Candida species, were investigated using the agar diffusion method. The results showed interesting antimicrobial potentials of both experimented kombucha teas against the tested microorganisms, except Candida krusei. The green fermented tea exhibited the highest antimicrobial potential. Indeed, it showed large inhibition zones against Staphylococcus epidermidis (22mm), Listeria monocytogenes (22mm) and Micrococcus luteus (21.5mm). Furthermore, interesting anti-Candida potential was revealed by the reaction of green tea kombucha against Candida parapsilosis. PRACTICAL APPLICATIONS The black fermented tea is the original and most popular preparation. This research has focused on the investigation of the antibacterial and antifungal activities of the kombucha prepared from green and black teas against a large number of human pathogens to determine and to compare the potential of the two kombucha drinks. The results showed a broad antimicrobial spectrum of kombucha against a range of pathogenic Candida involved in several candidoses. Moreover, the data showed that the antibacterial potential of kombucha prepared from green tea was higher than that of the original kombucha tea. Considering the antimicrobial activity demonstrated against a wide range of pathogenic bacteria and clinical Candida species, kombucha may be very healthful. As resistance to antimicrobial agents has become increasingly an important global health problem, these findings would be very promising and could be useful as an alternative to current synthetic antimicrobial drugs.