Sushi

Ingredient

　Original sushi was called "narezushi". Fish and rice were salted away for
two or three months and were fermented. A lactic acid bacterium makes
rice sour. Sourness of rice moves to fish. Fish were hard to rot thanks to
a lactic acid bacterium, and were able to be saved for one or two years.
In addition, people could take calcium abundantly by eating only a fish to
a bone entirely.