Shizuoka's food cultureKnow

Canned tuna is a familiar sight on the dinner table, used in a variety of dishes such as sandwiches, salads, and pasta. But did you know that Shizuoka Prefecture is the largest producer of tuna in Japan? Shizuoka Prefecture is a canned food kingdom, with over 10 canned food manufacturers. Its national share of canned tuna is as high as 97%. Why is canned tuna production so popular in Shizuoka Prefecture? We visited STI Sanyo Co., Ltd., a food manufacturer that produces canned tuna in Yaizu City, Shizuoka Prefecture, and spoke to them.

Yaizu City is located in central Shizuoka Prefecture. It has long prospered as a fishing town, and Yaizu Fishing Port is known as the base of deep-sea fishing, boasting the largest catch of tuna and bonito in Japan. STI Sanyo is located near this port.

"In the days before quick-freezing technology was available, our location near Yaizu Fishing Port was ideal for processing tuna and bonito into canned tuna while keeping them extremely fresh."

These are the words of Takashi Hashimoto, president of STI Sanyo Co., Ltd. The company has been manufacturing canned tuna for many years since it was founded in 1950. Hashimoto explains the origins of canned tuna as follows.

"In the 18th and 19th centuries, Napoleon sought ideas for preserved foods to solve his army's food supply problems. The solution he adopted was vacuum-packed, heat-sterilized, and bottled food. Later, canned food was invented, replacing the easily breakable glass bottles with metal containers. Canned tuna was invented in the United States in 1903 and became an instant hit upon its release. As a result, research into manufacturing methods was conducted throughout Japan in order to produce and export it domestically. Amidst this, Yoshio Murakami of the Shizuoka Prefectural Fisheries Experiment Station (now the Shizuoka Prefectural Fisheries and Marine Technology Research Institute) and the Yaizu Fisheries School (now Shizuoka Prefectural Yaizu Fisheries High School) collaborated to establish the first tuna canning method in Japan in 1929."

After that, several canned tuna manufacturers were established in Yaizu and exported their products to the United States and Canada. The high quality of the products was recognized and they became popular there. However, due to trade friction and other factors, exporting became difficult, and each manufacturer began to focus on domestic distribution. Gradually, canned tuna became a regular part of Japanese dining tables.

The packaging of STI Sanyo's tuna cans throughout history.

Currently, many manufacturers process their canned tuna overseas, but STI Sanyo handles the entire manufacturing process at its own factory in Japan, and has faithfully continued to use the same manufacturing method that was first established in 1929, from 1950 to the present day.

"Our canned tuna is sealed using the traditional method of 'double-wrapping,' in which the can body, called the can body, and the can lid are overlapped and wrapped around each other. Also, while many other manufacturers use yellowfin tuna in their products, we basically use long-fin tuna. This is because it has a white color, looks good, and is soft and easy to eat. The oil we use in our cans is light and refreshing cottonseed oil. In recent years, we have developed a wide variety of products, such as canned tuna in olive oil and canned tuna made with the head meat of southern bluefin tuna."

We had the opportunity to tour the factory to see how canned tuna is made.

On this day, canned tuna was being made using bigeye tuna and bonito. The photo shows the quick-frozen bigeye tuna being thawed. It is thawed overnight under running water.

The thawed fish then moves on to the steaming process, where it is steamed in a large steam pot. Small fish are placed whole, while larger fish are cut up and then placed in the pot. The temperature and time are adjusted depending on the type and size of the fish. The steamed fish is then left to cool overnight.

In the next process, the head, organs, bones, skin, etc. are removed, and the blood and small bones are carefully removed before inspection.

The removed parts are used as livestock feed.

After the fish is cleaned and separated into just the flesh, it is fed into a special machine and flaked to a certain size. It is visually checked for any foreign matter before being packed into cans.

Next, add the seasoning and oil.

The air is removed from inside the can and then it is sealed using the traditional double seam method.

After using a cleaning machine to remove any dirt from the outside, the potatoes are arranged in baskets and placed in a large steam boiler to sterilize them with 115°C steam for 70 minutes.

After the expiration date is printed, the entire quantity is checked with an X-ray inspection machine before being packed into boxes and then shipped.

It takes about three days for the raw materials to be turned into a finished product and shipped, and about 3 cans are produced each day.

Finally, we asked Hashimoto about his recommended way to eat canned tuna.

"The basic way to eat tuna is to put it on top of rice and add a little soy sauce. This allows you to enjoy the natural flavor of the tuna."

Canned tuna is a hidden specialty of Shizuoka Prefecture. Please try it and experience its deliciousness once again.