Mr. Yakult: Shirota Minoru, the microbiologist behind Japan’s most popular health drink


In the same year, Shirota received his doctorate in medicine and became a lecturer at Kyoto Imperial University. However, his work was far from over.

Shirota at his microscope.

The Birth of Yakult

Shirota firmly believed that the key to health was “not treating disease, but preventing contamination.” As such, he wanted to develop a dietary supplement that would make the Shirota strain available in a consumable form to as many people as possible. He also believed that good health should be available to all people, regardless of wealth or status.

He developed nothing but the internationally renowned probiotic drink Yakult, a milk-based fermented drink containing billions of units of the Shirota strain. (The name Yakult comes from the Esperanto word for yoghurt, “jahurto”). [7]

dr Shirota began marketing Yakult in 1935 by distributing individual bottles to patients in his area. However, word got around quickly and demand skyrocketed. So he hired a door-to-door sales team to provide both the drink and information to potential customers. The business grew like a grassroots movement and sold for as little as 5 yen, or as Shirota put it, “the price of a postcard and a cigarette”.

Eventually, the business expanded not only in Japan but also overseas, soon reaching over 500 branches worldwide. Shirota established the Yakult headquarters in Tokyo in 1955 and assumed the position of chairman and director of the research institute. [4][8]

Two classic bottles of Yakult.

Yakult ladies

During the war, Shirota took an innovative approach to making Yakult more widely available throughout Japan. To keep the business going, he had to make sure Yakult could still reach people in perfect condition, on time, and in all weathers. This required workers who were patient, earnest, and committed to their mission. And who better fulfilled these requirements than a housewife?

So while the men were on the battlefield, Shirota hired women as part-time distributors to distribute yakult door-to-door. It was an innovative approach as women rarely worked outside the home. But Shirota and his team of hard-working housewives stood strong. In 1963 the official Yakult Ladies Home Delivery System was established. Soon, Yakult ladies on bicycles with oodles of Yakult in tow became a regular sight across Japan. [7]

A Day in the Life of a Yakult Lady

Yakult hires ladies to sell their products door to door at home and even in the office. Yakult distributes its products in two ways: direct sales (i.e. supermarket…

A video with modern “Yakult Ladies”.

Yakult moves with the times

Yakult as a company always keeps its finger on the pulse and occasionally releases new versions in response to new research and health trends. The latest release was Yakult 1000, which came out last April and features a whopping 100 billion units of the Shirota strain! Yakult containers have also undergone a number of changes.

Yakult started with glass milk bottles. However, the cost of production increased, as did the weight the Yakult ladies had to carry. Shirota switched to smaller, lighter, and cheaper plastic containers in 1968. The now iconic design was a novel idea back then. The compact containers fit in the palm of your hand and were easier to hold for small children and the elderly with poor grip. The polystyrene material was hygienic and safe, and the aluminum foil cap prevented air from entering and spoiling the drink. The small 65ml size was also a safe amount for immediate drinking for children and the elderly.

Shirotaism & Yakult corporate culture

dr Minoru Shirota proposed many key ideas in preventive medicine during his research. These ideas now form the essence of Yakult and have been collectively referred to as “Shirota-ism”. The three key terms are:

  1. Medicine should be used for prevention rather than cure.
  2. A healthy gut promotes longer life.
  3. Good health should be accessible to everyone, regardless of wealth or status. [5]

Shirotaism also forms the basis of the company’s inclusive corporate culture. Matsumoto Masatoshi, Head of Human Resources at Yakult, said, “I believe that because all employees have adopted Shirotaism, we have created a corporate culture where everyone can work together peacefully.” [6]

Yakult headquarters takes equal employment seriously. At least 50 employees with disabilities have been working at Yakult since 2018. According to Matsumoto:

“We don’t have any special departments or posts for people with disabilities. All roles and career development opportunities are open to all. What we emphasize is the ability to work as team members in all of our offices across the country. In other words, as long as you can make the most of your abilities, anyone can play an active role. However, during recruitment, full-time public health nurses always have interviews to discuss the individual’s disabilities and any necessary considerations we need to make from a professional perspective. After work, we make sure to contact individuals through HR. In addition, public health nurses are available to employees for advice regarding their disability. The surrounding employees also provide the necessary support. We do this because we value our employees.”

Matsumoto [6]

The legend of Shirota Minoru lives on

Minoru Shirota died in 1982 at the age of 82, testifying to the success of his brand and the fruits of his labor. He has achieved the goal he set decades ago of providing people around the world with a means to a healthier gut at an affordable price in the form of a small, probiotic drink.

Yakult is currently available in over 30 countries. There is even a Shirota memorial museum at the Central Research Institute of Yakult Headquarters in Kunitachi City, Tokyo. And the Yakult company, as well as the Central Research Institute itself, continue to develop new research and technology.

Although Japan has never been a milk consuming nation, Yakult’s insane popularity is evident. Not only dr. Shirota Minoru achieves his goal. He created a legend. And that legend lives on in the form of a tiny, iconic bottle: Yakult.

Various labeled Yakult knockoff brands at a local supermarket in Tokyo.
Various Yakult knockoff brands at a local supermarket in Tokyo. Note that the original itself is sold out. (Photo by Noah Oskow.)

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[1] 代田稔. Wikipedia JP

[2] 長野県とヤクルトのつながりって?[長野県からはじまるヤクルト誕生秘話]. Yakult

[3] 昔の起業家 – 代田稔 (ヤクルト).起業x小学生

[4] 沿革. Yakult

[5] 代田イズム. Ehime Tobu Yakult

[6] 「代田イズム」のもと誰もが活躍できる風土が生まれる. Sana archive

[7] ヤクルトのシロタ株の由来になった代田稔(しろたみのる)さんって誰?好奇心ブログ

[8] ヤクルト:毎日2400万人が愛飲する乳酸菌飲料のパイオニア.ニッポン・ロングセラー考

[9] 知れば知るほど「シロタ株」. Yakult

[10] ヤクルト. Wikipedia JP


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