The inhibitory effect of hydrolytic products of starch on in vitro colonization by Streptococcus mutans.

Synthetic culture medium containing potato starch and 1 gm% sucrose, with and without human parotid saliva, were pre-incubated. Filtrates from these mixtures were then incubated with Streptococcus mutans. S. mutans colonization on glass rods was suppressed in the cultures using filtrates from saliva and starch interaction. No inhibition was noted in filtrates pre-treated with parotid saliva in the absence of starch. The results suggest that the hydrolysis of starch by saliva yields by-products which inhibit in vitro S. mutans colonization.