Fermented food is part of our ancestors’ wisdom applied to preparing for the winter cold. Dr. Takeo Koizumi, Fukushima-born emeritus
professor at the Tokyo University of Agriculture and a researcher of fermented food, spoke with the Japan Journal’s Osamu Sawaji about
this most nutritious of comestibles.
You eat and study fermented food from around the world. What are the characteristics of fermented food in Japan?
Dr. Takeo Koizumi: One major characteristic is that Japan has so many types of fermented food. Miso, soy sauce, sake, natto (soy beans) and katsuobushi (dry bonito) are Japan’s most famous fermented foods. Europe has its own fermented foods in yogurt and cheese, and Asia has baijiu (China), nuoc mam (Vietnam), and nam pla (Thailand), yet no single country other than Japan has so many types of fermented foods. The number of such foods is so high because the country is humid and the conditions are suited to reproducing microorganisms that ferment food materials. Since Japan also has abundant food materials such as fish, vegetables and grains, there are naturally more types of fermented food.
Fermenting food makes it capable of being stored for long periods of time. In the days when there were no refrigerators, fermentation was necessary to preserve food. The Japanese eat a great deal of fish, so there are numerous fermented foods using fish. Well-known examples are shiokara made of cut squid and its intestines salted and fermented, and narezushi made of fish pickled and fermented together with rice.
The Tohoku region in northeast Japan has a particularly wide variety of fermented food. Why is that?
One reason is its harsh winter climate. Since people could not harvest farmed products in the winter because of the cold and snow, they made fermented foods that could be preserved for cold months. They have a particularly wide variety of tsukemono (pickles). They pickled vegetables such as daikon radish, cucumber, Chinese cabbage and eggplant in a tsukedoko (bed) of miso, soy sauce and koji (rice malt). Vegetable tsukemono not only contained abundant vitamins made by microorganisms but was also full of fiber and extremely healthy. Tohoku was traditionally an agricultural region. People sweat from farm work in the summer and lose salt. Tsukemono contains a great deal of salt that replenishes people’s supply. The people of Tohoku needed fermented food in order to survive.
What other fermented foods do the people of Tohoku frequently eat?
They eat natto, made by fermenting soybeans. Among the prefectures with the largest consumption of natto in Japan are Fukushima (number one), Akita (two) and amagata (four)—all in the Tohoku region. Today, the people of Tohoku commonly eat natto on rice as do people of other areas, but during and before the Meiji period (1868-1912), they ate it in their miso soup. Since the Nara period (710–794), the Tohoku farmers grew rice in the fields and soybeans on the ridges between them. The people of Tohoku put tofu in their miso soup together with natto. Tofu and miso are also made of soybeans. Prior to the Meiji period, the Japanese people, including those of Tohoku, ate scarcely any meat, but soybeans have as much protein as meat. People were thus able to obtain plenty of protein from miso soup, natto and tofu without having to eat meat, which is why the people of Tohoku were able to build stamina to get through the cold winter.
Are there any fermented foods of Tohoku that you would like people of the world to try?
Many fermented food products have a unique smell and taste and may not suit the palates of people overseas who are not used to them. But I
think iburigakko of Akita Prefecture is one food that anyone can eat and enjoy. Iburigakko is daikon pickled in nukazuke (salted rice bran) and smoked with wood. There are many food products around the world that are smoked; such as coffee, whisky and ham. Yet iburigakko is the only food in the world that smokes fermented pickles. As with smoked food of other countries, iburigakko smells of wood smoke, which is why I believe people of other nationalities would have no problem eating it.
The Tohoku region and Japan have such an abundance of fermented foods. Expo Milan 2015, themed“ Feeding the Planet, Energy for Life,” will take place in May–October 2015, and I will help introduce Japanese fermented foods. I am hoping to take this opportunity to have people of the world taste the wonders of these foods.