Evaluation of Microbiological Contamination of Black and Green Teas

Abstract

The study aimed to determine the level of microbial contamination of black and green teas with different degrees of fragmentation. The microbiological analysis we conducted on 18 black and green teas available commercially on the market. Solutions were prepared from the weighed samples and then inoculated on sterile microbial media. Teas in bags proved to be the most polluted among the tested tea groups. Statistical analysis indicated significant differences in mycological contamination between black and green teas of various degrees of fragmentation. Green tea in bags manifested the highest fungal contamination-9.3×10 3 CFU/g, significantly exceeding the other teas. Isolated fungi belonged to Aspergillus sp., Cryptococcus sp., Rhizopus sp., Mucor sp., Penicillium sp. and Cladosporium sp. The lowest number of fungi we observed in the group of green leaf teas-1.7×10 2 CFU/g. We recorded the most significant number of Gram-positive bacteria in deciduous black tea-1.8×10 3 CFU/g. The correlation between the degree of tea fragmentation and their microbial contamination has been demonstrated. Potentially pathogenic bacteria isolated from black and green tea can pose a threat to the health of consumers.