The Art of Cultivating the Perfect Oyster

If you squeeze a lemon over a raw oyster and slip it into your mouth, the aroma of the beach fills your mouth, along with a rich sweet taste. But behind the delicious flavor is the reality of a risk of food poisoning. Isn’t there some way to eat raw oysters safely? One oyster farm took on this desire from oyster lovers across the globe, head on, and managed to succeed in raising oysters with a low risk of food poisoning. That farm is the Sato Oyster Farm located in Matoya Bay on the Shima Peninsula in Mie Prefecture. Creating these oysters, known as Matoya oysters, required the patiently accumulated research results of a single pioneer, and the efforts of the people at the farm who inherited the pioneer’s wishes and techniques till this day.

Making Young, Delicious Raw Oysters with Shells the Main Dish

As we visit the Sato Oyster Farm in Matoya Bay, we hear a light, banging sound. As we get closer to the source of the sound, we see someone taking something that looks like a knife and inserting it, then scraping, into what looks like a rock-like clump that appears to be black and rugged.

Sato Fumihiko, the 4th generation here at Sato Oyster Farm, tells us that these small clumps are oysters.

When asked, Fumihiko tells us that oyster cultivation begins by procuring immature oysters that have been attached to scallop shells. They are then hung from a raft perpendicularly, and are left to grow in the gentle waters of Matoya Bay for about a year and a half until they can be eaten. They are then hoisted up, and any oysters requiring a little more time to grow are placed in a basket and put back in the water, waiting quietly until they have grown to the ideal size. What I saw earlier was someone breaking off mature oysters, removing dirt from them, separating them by size, and checking to see if they could be sold with their shells.

“At our farm, we mainly have oysters that can be offered raw, and among those, our main products are the oysters with shells. Oysters that can be sold with their shells are some of the best oysters on the market. About 20% of oysters can be sold this way.”

Oysters with their shells are as valuable as they are fresh and delicious. That is why the raw oysters offered at high-end restaurants are served with the adductor muscle still attached; without completely removing the oyster from its shell. This is definite proof that it is not a shelled oyster.

”Shall we open one up?”

As Fumihiko says this, he takes an oyster in his hand, inserts his knife into part of the flat shell, and as he turns the knife, the shell opens before we know it. And from the shell appears a glossy, plump oyster.

“Oysters will keep getting bigger and bigger if left in the ocean. But when considering taste, the younger ones are better without a doubt. The thin outer part, called the mantle, is also soft and has a good texture in young oysters. At our farm, we ship oysters that are about one and a half years old. They are small enough that you can eat them in one gulp, and while that may seem too small, we want to create oysters that have as little bitterness as possible while making you want to eat more after eating just one.”

Taking up Fumihiko’s invitation to try one, I tasted one of his proud raw oysters, and just as he had said, it is the right size, both plump and tender. There is no foul smell that would require squeezing a lemon, and the sweetness and umami fill my mouth, supported by a moderate, natural saltiness.

While there are also cultivated oysters that are grown for two or three years, one of the reasons why we are able to raise delicious oysters in the short time of just a year and half is the environment that Matoya Bay is blessed with. The Bay has abundant, high-quality phytoplankton which act as food for the oysters as nutrients from the forest flow into the Bay through three separate rivers that flow from the forests of Ise Shrine and elsewhere. The Bay also maintains an excellent water temperature that doesn’t get too cold that the oysters enter hibernation, with its eastward location being beneficial to the water temperature despite being a temperate region. In addition, the waves are also gentle. All of these features are perfect for cultivating oysters.

The person who discovered that Matoya Bay was the perfect place for cultivating oysters in this way was Sato Tadao, the founder of Sato Oyster Farm and Fumihiko’s grandfather. It was Tadao who discovered how to raise oysters in a short time using the hanging oyster cultivation method, and the cleaning technique that allows the oysters to be eaten raw safely. In other words, he was a pioneer in oyster cultivation.

The Founder’s Idea Gave Birth to a Radical Cleaning Technique

Tadao began cultivating oysters around 1928, around the time when many hotels were being built that incorporated foreign culture. At that time, oysters were already eaten raw in other countries, so Tadao must have thought about offering raw oysters in hotel restaurants that were visited by many overseas guests. But the oysters in Japan at the time had a high risk of food poisoning, even though they were delicious. Serving raw oysters wasn’t a reality at the time.

The reason for this is in the oyster’s biology. Every hour, oysters take in close to 20 liters of sea water, extract food, and then excrete the leftover water. In other words, sea water passes through the body of the oyster and is filtered for food. However, there is a variety of bacteria in normal sea water, and oysters continue to take in this bacteria-filled sea water, meaning bacteria always exists within the oyster’s body. Additionally, there is no way to avoid the risks of food poisoning as bacteria can reproduce easily within the oyster’s body due to the oyster’s high nutritional value.

So what must be done in Japan’s oyster cultivation in order to create delicious raw oysters that can be safely eaten? As Tadao thought about this, he had an idea. “Oysters have bacteria because the sea water has bacteria. So what if we removed the bacteria from the sea water?”

After this, he learned through research that ultraviolet radiation has the effect of removing bacteria, and that oysters expel all ocean water from their bodies in about 18 hours, so his idea was further expanded, and he arrived at a solution in 1953. This method involved removing as much of the unwanted bacteria from within the oysters’ bodies by hoisting up oysters from the sea and then keeping them for 20 hours in sea water that had been sterilized with an ultraviolet lamp (ultraviolet rays). This unique technique is the greatest characteristic of Matoya kaki, including those cultivated at Sato Oyster Farm.

“Our cleaning method is basically unchanged from the method developed by my grandfather. This is because the quality of the original method was high. The sea water sterilization pool is intentionally set up with a flow of water, and it was all really well thought out. But because of that, it is quite difficult to maintain!”

Sato Oyster Farm did not make this cleaning technique a trade secret. We’re told that this cleaning technique was happily taught to others who were cultivating oysters in the same way in Matoya Bay, rather than keeping it to themselves. They were able to do this surely because they were very confident in what they were doing.

Sato Oyster Farm‘s Matoya kaki, raised by over four generations, was able to be exported live to Singapore for the first time from Japan in January of 2019, with their techniques and safety having been recognized by Mie Prefecture and Zengyoren. As the life of raw oysters depend on speed, transporting them to faraway places is no easy feat, but they were able to make this a reality through Mie Prefecture’s own distribution route direct between producers and customers. Born out of a radical idea of one researcher and his honest research, and through techniques that are passed down to this day, the clean Matoya kaki oysters continue to evolve while maintaining their delicious flavors, even being delivered directly to overseas gastronomists as safe, raw oysters.