Evaluation of the antimicrobial activities of green tea extract in media and sterilized milk

Yeasts and molds are considered as major causes of spoilage of acidic foods. Various studies have shown that green tea (Camellia sinensis) has antimicrobial properties. the study aimed to investigate the antiyeast activity of green tea extract in the plate and sterilized milk. Total phenol and flavonoid content were determined by colorimetric method. Anti-yeast activity of green tea against Saccharomyces cerevisiae, Kluyveromyces marxianus and Rhodotorula glutinis was measured using well diffusion and disk diffusion agar. The minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) of green tea were examined by micro dilution in plate and by macro-dilution in sterilized milk in tubes. MIC of green tea extract was in range of 12.5 to 25 mg/ml in microdilution method and 6.5 to 25 mg/ml in macro dilution method. Kluyveromyces marxianus was the most resistant yeast against green tea extract. Consequently, because of the positive effect of green tea extract against the studied yeasts, it could be utilized as an anti-yeast compound in food and drug technology.