The total includes the initially reported 293 pupils and staff at three elementary schools, plus six middle-school students and eight kitchen workers. The implicated dish was grilled hamachi with yuzu pepper.
The health authority ordered the Higashiizumo school meal centre to stop operating from 30 October through 3 November. Symptoms followed meals on 29 October; the health order and histamine identification are the new developments announced on 30 October.
The precise circumstances that caused histamine to form remain under investigation. Detection in the dish does not by itself establish fault by a particular actor in the food supply chain.