Abstract
Food poisoning caused by enterohemorrhagic Escherichia coli (EHEC) has occurred frequently in schools and homes for the elderly since 1990. Drinking tea is popular in Japan and the antibacterial effect of catechin has been reported. We studied the inhibitory effect of tea and catechin drinks on growth and vero toxin (VT) production in EHEC O 157. Growth of each strain of E. coli was inhibited by a catechin-containing medium. Stronger inhibitory effects were recognized in green tea medium and black tea medium, which contained more catechin (epigallocatechin gallate and epicatechin gallate) possessing galloyl moiety. In MV1184 and HK, stronger inhibitory effects were recognized in green tea medium and coarse tea medium, which contained more caffeine. These data support the possibility that factor other than catechin have an inhibitory effect on bacterial growth. Three bacteria were cultivated in LB broth medium and the number of colonies was measured. The growth of EDL931 was fastest followed by HK; MV1184 showed the slowest growth. HK and EDL931 produced vero toxin and its production was inhibited or prevented in each medium (black tea medium, two kinds of green tea medium and coarse tea medium). These data supports the high possibility that food poisoning is prevented by drinking tea.
