TOKYO: With frozen food items selling well in Japan on the back of steady eat-at-home demand due to the novel coronavirus pandemic, technologies to freeze sushi have been improving drastically.

Such technologies not only allow consumers to enjoy at home fresh toppings for sushi, typically, seafood, but also a freshly-made texture of “shari” white rice seasoned with a combination of vinegar, sugar and salt.

Last year, Toshin Sea Foods Co., which runs fish stores mainly in Tokyo, started online sales of packages of frozen sushi with toppings including tuna, horse mackerel and shrimp.

Since it is difficult to preserve the quality of sushi, especially shari, with conventional freezing methods, Toshin Sea Foods uses a rapid-freezing machine developed by Technican Co., based in Yokohama, Kanagawa Prefecture, south of Tokyo. The rapid freezer, which involves the use of alcohol and other liquid, allows shari to be moist and toppings, even blue-backed fish, to stay fresh after defrosting.

Shari and toppings are vacuum-packed separately. For defrosting, the package of toppings needs to be soaked in iced water for about 20 minutes and shari needs to be warmed up in a microwave. After putting toppings on top of shari, people can enjoy “nigiri zushi,” or hand-shaped sushi.

Toshin Sea Foods plans to add a new variety of seasonal toppings for sale. It also aims to start selling frozen sushi at physical stores.

A worker at Tokyo’s Toyosu wholesale food market pinned hopes on the improvement of freezing technologies, saying that it would “allow people to enjoy the taste of various in-season fish at any time.”

JIJI Press