Nattō (納豆), spelled as natto in standard English language use, is a traditional Japanese food made from whole soybeans that have been fermented with Bacillus subtilis var. natto.[1] It is often served as a breakfast food with rice.[2] It is served with karashi mustard, soy or tare sauce, and sometimes Japanese bunching onion. Within Japan, nattō is most popular in the eastern regions, including Kantō, Tōhoku, and Hokkaido.[3]

Nattō on rice
Place of originJapan
Region or stateEast Asia
Main ingredientsFermented soybeans

Nattō is often considered an acquired taste because of its powerful smell, strong flavor, and sticky, slimy texture.[4][5][6][7][8] A 2009 survey revealed that 70% of Japanese people find the taste pleasant, and others who may not find the taste of the food pleasant still eat it out of habit.[9]


Sources differ about the earliest origin of nattō. One theory is that nattō was codeveloped in multiple locations in the distant past, since it is simple to make with ingredients and tools commonly available in Japan since ancient times.[10]

Legendary origins

Opening and stirring a container of nattō

One story about the origin of nattō attributes it to the samurai Minamoto no Yoshiie (1039–1106), who was on a campaign in northeastern Japan between 1086 AD and 1088 AD. One day, his troops were attacked while boiling soybeans for their horses. They hurriedly packed up the beans, and did not open the straw bags until a few days later, by which time the beans had fermented. The soldiers ate it anyway, and liked the taste, so they offered some to Yoshiie, who also liked the taste.[11][12]

Another story involves Prince Shotoku (574–622), who is said to have wrapped the leftovers of boiled soybeans in straw bags for his horse. As people happened to eat these fermented beans and found them delicious, this type of fermented stringy beans soon gained popularity in Japan because of its unique taste and strong flavor.[13]

Chinese douchi

Before nattō, there was a similar dish of fermented black soybeans food in China called 豉 (chǐ) or douchi (Chinese: 豆豉; pinyin: dòuchǐ). These are salted, fermented-and-aged whole soybean seasonings or condiments invented in China and spread throughout East Asia. It is usually made from fermented soybeans and with an ample amount of salt; however, the ingredients and producing method differ in Japan. Chinese use both black and yellow soybeans to produce douchi whereas Japanese nattō only uses yellow soybeans. The amount of salt used also makes difference between douchi and nattō on their taste and appearance.[14][15]

The cultivation method of soybeans and rice was imported from China to Japan during the Yayoi period, and later on, the circulation of salt began to flourish in Japan. This provided an opportunity for the production of douchi to become popular in Japan. Because salt was expensive and valuable at the time, it has been suggested that nattō was invented by accident during the production of douchi.[11] [13]

A wooden slip was excavated in Heijō-kyō, which had the Chinese character 豉 written on it.[13][14] The excavation of the slip is considered an evidence to support the hypothesis that the invention of nattō was based on the Chinese douchi imported to Japan.

The Chinese character 豉 entered Japan in the 8th century. It was pronounced "kuki" until the 11th century, when nattō became a new name for fermented soybeans.[15]

Commercialization in the Taisho period

A change in the production of nattō occurred in the Taishō period (1912–1926), when researchers discovered a way to produce a nattō starter culture containing Bacillus subtilis without the need for straw, thereby simplifying the commercial production of nattō and enabling more consistent results.[16]


Nattō, 100 grams
Nutritional value per 100 g (3.5 oz)
Energy883 kJ (211 kcal)
12.7 g
Sugars4.89 g
Dietary fiber5.4 g
11 g
19.4 g
Thiamine (B1)
0.16 mg
Riboflavin (B2)
0.19 mg
Niacin (B3)
0 mg
Pantothenic acid (B5)
0.215 mg
Vitamin B6
0.13 mg
Folate (B9)
8 μg
57 mg
Vitamin C
13 mg
Vitamin K
23.1 μg
217 mg
8.6 mg
115 mg
1.53 mg
174 mg
729 mg
8.8 μg
7 mg
3.03 mg
Other constituentsQuantity
Water55 g

Percentages are roughly approximated using US recommendations for adults.

Nattō is 55% water, 13% carbohydrates, 19% protein, and 11% fat (table). In a 100 gram (3.5 oz) reference amount, nattō supplies 211 calories and is a rich source (20% or more of the Daily Value, DV) of several dietary minerals, especially iron (66% DV) and manganese (73% DV), and vitamin K (22% DV). Nattō contains some B vitamins and vitamin C in moderate amounts (table).

Appearance and consumption

Nattō has a distinctive odor, somewhat akin to a pungent aged cheese. Stirring nattō produces many sticky strings.[1] The dish is eaten cold with rice, mixed with the included soy sauce or karashi mustard. Other ingredients such as long onion or kimchi are often added.

Nattō is frequently eaten as nattō gohan (nattō on rice). Nattō is occasionally used in other foods, such as nattō sushi (nattōmaki), nattō toast, in miso soup, tamagoyaki, salad, as an ingredient in okonomiyaki, chahan, or even with spaghetti. Sometimes soybeans are crushed before fermenting.

Many find the taste unpleasant and smelly while others relish it as a delicacy. Nattō is more popular in some areas of Japan than in others. Nattō is known to be popular in the eastern Kantō region, but less popular in Kansai.[9]

For those who dislike the smell and texture of natto, "dried natto" and "fried natto" were developed around 1990. The smell and stickiness are reduced, making it easier to eat for those who do not like conventional natto. Another type of fermented soybeans called "Mamenoka (豆乃香)" has also been developed by improving the soybean and natto bacillus varieties to make it less sticky.[17]

Production process

Nattō is made from soybeans, typically nattō soybeans. Smaller beans are preferred, as the fermentation process will be able to reach the center of the bean more easily. The beans are washed and soaked in water for 12 to 20 hours to increase their size. Next, the soybeans are steamed for six hours, although a pressure cooker may be used to reduce the time. The beans are mixed with the bacterium Bacillus subtilis, known as nattō-kin in Japanese. From this point on, care must be taken to keep the ingredients away from impurities and other bacteria. The mixture is fermented at 40 °C (104 °F) for up to 24 hours. Afterward, the nattō is cooled, then aged in a refrigerator for up to one week to allow the development of stringiness.

In nattō-making facilities, these processing steps have to be done while avoiding incidents in which soybeans are touched by workers. Even though workers use B. subtilis natto as the starting culture, which can suppress some undesired bacterial growth, workers pay extra-close attention not to introduce skin flora onto soybeans.[18]

End product

Mass-produced nattō is sold in small polystyrene containers. A typical package contains two, three, or occasionally four containers, each 40 to 50 g. One container typically complements a small bowl of rice.

Nattō odor comes from diacetyl and pyrazines, but if it is allowed to ferment too long, then ammonia is released.[19]

KNT (Kinema-Natto-Thua Nao) triangle, connects the fermented soyabeans across Asia.

Many countries around Asia also produce similar traditional soybean foods fermented with other bacteria and fungi, such as shuǐdòuchǐ (水豆豉) of China, cheonggukjang (청국장) of Korea, tempeh of Indonesia, thuanao (ถั่วเน่า) of Thailand, kinema of Nepal and the Himalayan regions of West Bengal and Sikkim, tungrymbai of Meghalaya, hawaijaar of Manipur, bekang um of Mizoram, akhuni of Nagaland, and piak of Arunachal Pradesh, India.[3][20]

See also


  1. Hosking, Richard (1995). A Dictionary of Japanese Food - Ingredients and Culture. Tuttle. p. 106. ISBN 0-8048-2042-2.
  2. McCloud, Tina (7 December 1992). "Natto: A Breakfast Dish That's An Acquired Taste". Daily Press. Retrieved 25 December 2012. It is a traditional soybean breakfast food from northern Japan and it's called natto. [...] As a breakfast food, natto is usually served over steamed rice and mixed with mustard and soy sauce.
  3. Shurtleff, W.; Aoyagi, A (2012). History of Natto and Its Relatives (1405–2012). Lafayette, California: Soyinfo Center.
  4. Katz, Sandor Ellix (2012). The Art of Fermentation: An In-Depth Exploration of Essential Concepts and Processes from Around the World. Chelsea Green Publish. pp. 328–329. ISBN 978-1603582865. Natto is a Japanese soy ferment that produces a slimy, mucilaginous coating on the beans, something like okra. [...] The flavor of natto carries notes of ammonia (like some cheeses or overripe tempeh), which gets stronger as it ferments longer.
  5. A., M. (30 March 2010). "Not the natto!". Asian Food. The Economist. Retrieved 25 December 2012. ... natto, a food that has achieved infamy among Japan's foreign residents.
  6. Buerk, Roland (11 March 2010). "Japan opens 98th national airport in Ibaraki". BBC News. Retrieved 25 December 2012. ... natto, a fermented soy bean dish that many consider an acquired taste.
  7. "Natto Fermented Soy Bean Recipe Ideas". Japan Centre. Retrieved 25 December 2012. Natto are one of those classic dishes that people either love or hate. Like Marmite or blue cheese, natto has a very strong smell and intense flavour that can definitely be an acquired taste.
  8. "Preparing Nattou". Massahiro. Retrieved 28 March 2013. Preparing Nattou step by step, without using rice straw.
  9. NTT navispace 「納豆は好きですか?Do you like Natto?」 Archived 2012-11-21 at the Wayback Machine (in JA) reviewed 2012-12-8
  10. Deutsch, Jonathan; Murakhver, Natalya (2012). They Eat That?: A Cultural Encyclopedia of Weird and Exotic Food from Around the World. ABC-CLIO. p. 141. ISBN 978-0-313-38058-7. Retrieved May 20, 2016.
  11. "納豆 金のつぶ 納豆まめ知識|ミツカングループ商品・メニューサイト". Retrieved 2019-11-07.
  12. William Shurtleff; Akiko Aoyagi (2012). History of Natto and Its Relatives (1405–2012) (PDF). Soyinfo Center. ISBN 978-1-928914-42-6.
  13. "起源は?発祥は?知られざる納豆の歴史 | ピントル". 納豆専門ページ | ピントル (in Japanese). Retrieved 2019-11-07.
  14. "History of Natto and Its Relatives (1405-2012) - SoyInfo Center". Retrieved 2019-11-16.
  15. "History of Soy Nuggets (Shih or Chi, Douchi, Hamanatto) - Page 1". Retrieved 2019-12-14.
  16. Kubo, Y; Rooney, A. P; Tsukakoshi, Y; Nakagawa, R; Hasegawa, H; Kimura, K (2011). "Phylogenetic Analysis of Bacillus subtilis Strains Applicable to Natto (Fermented Soybean) Production". Applied and Environmental Microbiology. 77 (18): 6463–6469. Bibcode:2011ApEnM..77.6463K. doi:10.1128/AEM.00448-11. PMC 3187134. PMID 21764950.
  17. "糸引きの少ない納豆「豆乃香」の開発" (PDF) (in Japanese). Ibaraki Prefectural Industrial Technology Center. 2018-11-01. Retrieved 2021-11-22.
  18. "納豆が出来るまで。納豆の製造工程". 2004. Archived from the original on 2014-02-01. Retrieved 2013-09-15.
  19. Kada S, Yabusaki MY, Kaga T, Ashida H, Yoshida KI (2008). "Identification of Two Major Ammonia-Releasing Reactions Involved in Secondary Natto Fermentation" (PDF). Biosci. Biotechnol. Biochem. 72 (7): 1869–1876. doi:10.1271/bbb.80129. PMID 18603778. S2CID 30111356. Archived from the original (PDF) on 2017-12-07.
  20. Arora, Dilip K.; Mukerji, K. G.; Marth, Elmer H., eds. (1991). Handbook of Applied Mycology Volume 3: Foods and Feeds. CRC Press. p. 332. ISBN 978-0-8247-8491-1.
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