Study of the Anti-Bacterial Effects of Green and Black Kombucha Teas and Their Synergetic Effect against Some Important Gram Positive Pathogens Transmitted by Foodstuff

Kombucha is a traditional Asian drinks that consists of a symbiotic culture of yeast and some bacterial strains growing in sweetened black or green tea. This syrup is a practical drink with a long history that is produced through fermentation process based on collaboration system of yeasts, lactic acid and acetic acid bacteria. Kombucha tea shows strong anti-bacterial activity against a wide range of bacteria. In this study, first we evaluated the green and black Kombucha teas'anti-bacterial effect to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) against some of the standard pathogen bacteria transmitted by the foodstuff including: Bacillus cereus (PTCC 1015), Staphylococcus aureus (PTCC 1431) and Listeria monocytogenes (PTCC 1298); using macrodilution technique. Next, the synergetic effect the two teas was compared with the help of Cheakboard statistical relationship. The results showed that there was a huge difference between the studied Kombucha teas in terms of anti-bacterial properties. The minimum inhibitory concentration (MIC) against the studied bacteria for green Kombucha tea was 0.058 to 0.163 mg/ml and for black Kombucha tea it was 0.117 to 0.468 mg/ml. Among the studied bacteria, Staphylococcus aureus (PTCC 1431) was the most sensitive and Listeria monocytogenes (PTCC 1298) was the most resistant relative to others. In accordance with the calculations of Cheak Board statistical relationship, the black and green Kombucha teas showed antagonistic effects on each other.