Bosou

Bosou—also called nonsom, noonsom, tonsom, or tinamba in different Dusunic dialects—is a traditional fermented condiment of the Kadazan-Dusun people, who are indigenous to Sabah in East Malaysia. It is made by preserving vegetables, freshwater fish, or meat with salt, white rice, and pangi fruit (*Pangium edule*), which acts as the main preservative. The condiment has a notable salty and tangy taste. It is often eaten raw as a side or served with white rice, fried noodles, or bee hoon, but it is more commonly cooked together with other meats and vegetables.

Its counterpart in West Malaysia is pekasam, but bosou differs noticeably in its use of pangi fruit. After production, bosou must be kept in an airtight container because of its strong odor.

The practice of making bosou arose as a traditional way to prevent food waste, especially when there was a large fish catch or surplus vegetables, before modern refrigeration existed.

To prepare bosou, vegetables, freshwater fish, or various meats are mixed with white rice, salt, and pangi seeds. Although raw pangi seeds are naturally toxic, the Kadazan-Dusun have a method to remove the poison through fermentation. The mixture is placed in a plastic or glass jar and left to marinate for two weeks to a month. The bacteria in the rice break down carbohydrates into lactic acid, creating an acidic environment that preserves the food. Vegetable bosou (kinotuan) is safe to eat raw after seven days; fish bosou (sada) needs about three weeks to a month for the bones to soften enough to be eaten raw; and bosou made from Bornean wild boar meat must be cooked first to eliminate bacteria safely. Additional ingredients like chilies, ginger, and onion are often added to enhance the flavor. Most commercial bosou sold in jars at tamu markets is typically fermented for six to eight weeks.