Chemical and microbiological studies on Kenyan and Gabali Egyptian tea

Abstract

The present study was designed to compare the quality of Gabali Egyptian tea and Kenyan tea locally cultivated in Egypt. Gabali, black and green Kenyan teas were laboratory processed, then analyzed chemically and microbiologically for their quality evaluation. Representative results show that all samples of the 3 types were contaminated with aerobic mesophilic plate counts of the tea types varied from 6.1x103 to 2.2x108 cfu/g, spore-forming bacteria 1.1x102 to 1.6x104 cfu/g, coliforms (MPN) 0.36- 1.5 x101 cell/g, molds 2.3x102 to 3.0x104 and yeasts 1.2x102 to 5.8x103 cfu/g, in which gabali tea was the highest and black Kenyan tea was the lowest microbial count. Pathogenic bacteria were not in detectable level. The black Kenyan tea had the highest antibacterial activity followed by the green Kenyan tea with all solvents, but extraction of Gabali tea had antibacterial activity only by distilled water and water reflux. Total aflatoxin in concentration range of 6.1, 9.8 and >50 μg/kg in black and green Kenyan tea and Gabali tea, respectively. Phytochemical analysis of the tea samples revealed the presence of tannin in high level in black Kenyan tea (14.33%). Considering the results obtained, only black and green Kenyan tea had acceptable levels for all microbial factors in comparison with the Egyptian standards. It was concluded that Gabali tea may be high risk product and therefore, more studies are necessary to find methods of decontamination.