Japanese exports of sweet potatoes have been brisk thanks largely to technology to prevent spoilage and efforts to tailor the spuds to an increasing number of targeted areas around the world.

High-quality sweet potatoes from Japan are now being sent around Asia and to Europe, the United States and the Middle East.

Japan exported 6,200 tons of sweet potato in 2023, agriculture ministry statistics showed. The shipment value rose nearly tenfold to 2.9 billion yen ($19.1 million) over the last decade.

Exports surged particularly from 2018, after the operator of the discount store chain Don Quijote opened an outlet in Singapore in 2017 and Japan-made potatoes became a major hit in the city nation.

“Carefully selected Japanese potatoes with high levels of sugar content and quality were accepted as hot sweets,” said a public relations official from the Don Quijote operator.

Currently, sweet potatoes are served raw and baked at the company’s 47 outlets abroad.

LONG SHIPPING TIMES

Kushima Aoi Farm Co., located in Kushima at the southern tip of Miyazaki Prefecture, holds the largest share in Japan’s sweet potato exports, at 20 percent.

The agricultural corporation operates a 1,450-ton storage facility with about 100 staff members, half of whom are non-Japanese.

Kushima Aoi Farm annually handles 10,000 tons of sweet potatoes harvested from its own fields and 280 partner farms throughout Japan. Around 1,000 tons of the potatoes are exported via container ship to 11 countries and regions mainly for sales at local supermarkets.

It takes one to two weeks for the products to reach nearby nations, and more than a month for destinations in Europe, the United States and the Middle East.

Countermeasures to prevent potatoes from rotting during shipping are essential.

The temperature and humidity inside Kushima Aoi Farm’s storage house lined by shipping containers are kept high so that scratches on the potatoes from the harvest process can heal naturally.

Cork layers form over the scars like human scabs, stopping pathogen invasion and reducing the risk of spoilage in delivery.

POSITIVE OUT OF NEGATIVE

Minamihashi Shoji, an agricultural business in Kanoya, Kagoshima Prefecture, sprays peracetic acid to disinfect sweet potatoes at its storage house and lower the possibility of spoilage in the prolonged transportation.

The method was developed in response to the spread of foot rot, a kind of mold that blackens the leaves and stems of sweet potato plants.

The disease’s outbreak, which began in autumn 2018, devastated sweet potato output primarily in Kagoshima and Miyazaki prefectures.

Although the mold’s effects still linger, the disease has been brought under control to some extent through various approaches.

Ryusaku Yahata, 46, president of Minamihashi Shoji, recalled opening the door of his company’s warehouse at the time and discovering 500 tons of sweet potatoes rotting and steaming.

To battle the disease, Yahata came up with the idea of using peracetic acid. He said the strategy has proved helpful for potatoes that are exported, too.

“The new method was born in responding to foot rot,” Yahata said. “We successfully turned the trouble around.”

CATER TO VARYING TASTES

Kushima Aoi Farm, which organizes tasting events at local venues overseas, strives to cater to taste buds in each site.

The company said 99 percent of people “respond positively” when sampling Japanese-style baked sweet potatoes prepared with dedicated equipment.

However, consumers’ preferences vary by country and region.

The sticky Beniharuka variety is occasionally described as “too clingy” in Germany. The Miyazaki Beni variety, known for its flaky texture, wins over consumers in Hong Kong but sees less success in Southeast Asia, according to the company.

With this in mind, Kushima Aoi Farm secures a range of potato species to accommodate diverse tastes worldwide.

To ensure stable production of sweet potatoes throughout the year for exports, Kushima Aoi Farm signs contracts with farmers around the country, including in Kyushu, Hokkaido and Toyama, Ibaraki, Mie, Ehime, Yamaguchi and Okinawa prefectures.

Although the environment for potato exports may look favorable, the logistics costs are expensive. Accidentally delivering spoiled potatoes can result in huge losses.

Therefore, the profitability for exports is no higher than that in the domestic market.

Still, Shoto Horiuchi, 39, vice president of Kushima Aoi Farm, who is responsible for the overseas expansion plan, holds high expectations.

“Japan-made potato species will surely sell well internationally if we further improve their quality by refining maturing techniques,” he said. “We will be building distribution networks in and outside Japan to increase sales, for the sake of our many contract farmers.”