Natto Fermented Soybean Products

Natto Fermented Soybean Products

When they meet a foreigner who likes Japanese food, 90% or more Japanese will probably ask the following question,

“Do you like natto? Can you eat it?” “Natto” is a very unique type of food whose smell and flavor are so strong that the Japanese find it hard to believe any foreigners would dare approach it (How much nationalism is involved in this eccentric bit of acting is unclear). Natto is made by packing soybeans in straw, and then leaving them to ferment. Usually, it is left alone for a day, at a temperature of around 40 degrees. In this way, bacterium called Bacillus subtilis natto (known as nattō-kin in Japanese) attached to the straw multiply, and natto beans emerge from the ensuing fermentation process. Natto has a peculiar smell and an icky texture that do make it a bit of a mouthful for anyone experiencing it for the first time.

Ibaraki prefecture is now perhaps most well-known for its #1 natto production volume in Japan. The history behind this number can be traced back to the Meiji period, when a man named Seizaemon Sasanuma began selling natto as souvenirs upon the opening of the Mito line railway.

To tell the truth, we do not know exactly when natto was first made. According to the one theory, people of the Yayoi period from the third century BC to the third century AC lived in a pit house with a furnace inside, with hay and straw laid on the ground. This type of house was said to in a perfect condition for Bacillus subtilis natto to multiply. It is supposed that one day, boiled soybeans may have spilled on top of the straw, and that left alone, they then accidentally fermented into “natto”. The Japanese are averse to wasting food, so one can imagine the residents of such a house trying to taste this unknown substance, only to find it had gained unexpected and enhancing flavor.

Natto is often mentioned when speaking of food products with high nutritional qualities. Soybeans are rich in protein and help improve the immune system. Natto also contains isoflavone, which improves hormone balance, and lecithin, which regulates the functions of intestines, helps recover from fatigue, and kills bacteria. Furthermore, it is rich in enzymes, which prevent high blood pressure and help to dissolve blood clots, as well as calcium, magnesium and dietary fiber. There are many models and actresses out there who love eating natto as part of their effort to maintain their youth. For those worried about its strong smell, “less-odor natto” has been recently developed. As for those who don’t like the slimy threads that inevitably emerge from fermentation, dry natto is sold nowadays as well. Even if you find it’s not your cup of tea, natto is famous as a food that grows on people over time, so try to give it a few more chances if you can.


Photo by Ibaraki-Prefectural Tourism & Local Products Association

Related facilities