The effect of edible blue-green algae, Nostoc flagelliforme, Nostoc commune, and Aphanothece sacrum on the infection of Listeria monocytogenes was studied in mice. Fiveweek-old male ddY mice were administered orally with the hot-water extract of these algae (0.2 ml/day) for 7 days, and then inoculated intravenously with L. monocytogenes. The number of L. monocytogenes in spleen was counted on day 3. The hot-water extract of these algae showed the tendency to inhibit the growth of L. monocytogenes in spleen.
