Yoghurt becomes sourer the longer it is kept. It has been used for feeding young infants. Soybean products - Natto. Soaked, boiled soybeans are fermented for two days wrapped in straw or pinewood. Soaked soybeans are ground to a paste and heated.
Water is added.
The liquid is filtered and gypsum added. The resulting curd is moulded into cakes that are eaten fresh, dried, smoked, or fermented. Fermented rice and soybean. Thin slices of fungus-digested soybean. Bulgur wheat is soaked for several days in yoghurt and sour milk.