In summary, both polyphenols displayed growth inhibitory effects on the bacterium. Further, the antibacterial effects were dependent on dose, time of exposure and type of polyphenol. Gallic acid showed a
higher anti-E. coli effect compared to catechin. Mixtures of subeffective doses of gallic acid and an
effective dose of catechin produced growth inhibition halos similar to those produced by catechin alone.