The days pass quickly in Japan: I have to admit that this land knows how to make me feel good. Having had a chance to observe the most common habits, I begin to convince myself that the longevity of this population is the result of a common attitude towards serenity which generally keeps the Japanese far from any excesses. I can also notice it in my meals which are characterized by small portions. Nature here offers a wide variety of resources which are further enhanced by a great number of different food preparation methods that Japanese tradition cherishes. Among them, the supreme queen -the art of fermentation which describes much of the country's gastronomic offer.

Fermentation is the biological process in which bacteria and yeasts transform certain food components, very often sugars, into other substances such as acids, alcohol or carbon dioxide. As a result, it is possible to obtain a final product which is totally different from the one that generated it.

The list of Japanese products obtained through fermentation is long. Saké, the Japanese alcoholic beverage par excellence is obtained, for example, from the alcoholic fermentation of rice. The variety of rice used has a high percentage of starch which is responsible for the final content of ethyl alcohol in the beverage. Even if it has a great social value, like all alcoholic beverages, it should be consumed with moderation.

The miso is obtained by fermenting several cereals. It is a must-have of every Japanese meal. The large amount of vinegar marinated vegetables at the Japanese supermarket highlights the importance of introducing daily beneficial bacteria through the colorful vegetable offer into the Japanese diet. Such foods stand for the fermentation of fresh vegetables.

Nevertheless, the fermented soybean derivatives are the undisputed example of the fermentation techniques used in the East. Until a few centuries ago, this food was used exclusively in agricultural practices due to the presence of substances - called "antinutritional factors" - which may limit the absorption of certain nutrients. This is the case, for example, of the phytic acid present in the seeds, which makes it more difficult to absorb minerals such as calcium, iron and zinc. Specific fermentations can reduce the content of antinutritional factors: so the transformation of soybeans into tempeh, natto and soy sauce has allowed a more widespread and qualitatively better nutrition.

After the introduction of milk into human nutrition, which in Japan dates back to the second half of the nineteenth century, the use of fermentation also extended to this food, thanks mainly to the pioneering vision of a man of science. A microbiologist who devoted his study with particular determination to food fermentation in Japan was Minoru Shirota. He was the one who in the first decades of the twentieth century began to analyze potential health benefits of lactic bacteria foods. Shirota, who was also a physician, studied more than 300 bacterial strains in order to select one that could withstand gastric acid and bile salts to reach the intestine and colonize it. In his vision, the intestine's health was in fact the key to a more general level of well-being - a concept not common for the times, which have become more and more shared over the years and decades.

Only strong passion for work could produce great results: in 1930 he discovered the ferment that he later named, the Lactobacillus casei strain Shirota. Cultivating this specific bacterium in milk, which is particularly suited to the growth of lactic bacteria, gave birth to the drink he called Yakult. This product can be literally found everywhere in Japan. It is sold by elegant Yakult Ladies in nice uniforms who carry it in city streets on their bicycles or scooters.