Abstract:

The filter paper disc diffusion method was employed to determine the in vitro antibacterial activities of water extracts from Pu'er tea and green tea against 6 foodborne pathogenic bacterial species including L. monocytogenes, S. faecalis, E. coli, S. typhimurium, S. aureus and B. anthraci and the minimal inhibition concentrations (MICs). The results showed that the extract from Pu'er tea displayed higher antibacterial activity against L. monocytogenes within the concentration range of 1%－7% (m/V) and the MIC was 0.07 mg/ml, and this extract presented inhibitory activity against all the 6 bacterial species within the concentration range of 5%－7%, especially against B. anthraci. However, the green tea extract only demonstrated inhibitory activity within the range of 1%－2% against L. monocytogenes, with the MIC of 0.09 mg/ml, but at the concentration of 3% this extract exhibited inhibitory activity against other 5 bacterial species except B. anthraci, while it exhibited inhibitory activity against all the 6 bacterial species within the range of 4%－7%, having the highest activity against S. faecalis.

Key words: Pu’er tea, green tea, pathogenic bacteria, in vitro antibacterial activity, minimum inhibitory concentration (MIC)