Patent ID: 8003155

Claim:
A vacuum-packed frozen sushi product configured for microwave cooking, said vacuum-packed frozen sushi product comprising: a vacuumed, frozen and hermetically sealed flexible plastic packing bag which is vacuumed to a pressure of 600 mm Hg or lower; an open-topped plastic box having a top opening and a bottom, the top opening of which is formed as to be broader than the bottom, placed in said packing bag; a laminated metal foil placed on the bottom of said box; and a frozen sushi product which is formed by at least one shaped form of frozen boiled rice and a sushi material placed on a surface of each form of said at least one shaped form of frozen boiled rice, and which is contained in said box with its sushi material or materials each in contact with said laminated metal foil which is provided with portions upwardly extending from the bottom of said box along box walls to cover each of the sushi material or materials at least in part in the longitudinal direction or width direction or the longitudinal and the width direction; a space being formed in the packing bag around said sushi product in the vacuumed condition, which provides interspaces between the sushi product and the plastic box and between the plastic box and the packing bag, an inner surface of said plastic packing bag being in contact with an upper surface of the shaped rice section of said sushi product, said plastic packing bag, said plastic box, said laminated metal foil and said frozen sushi product being frozen together in a unified form, the space formed around the sushi product in said packing bag having a volume 0.2 to 0.6 times that of said sushi product at the time of thawing, by means of microwave, and after thawing, the resulting packed sushi product being configured to stand for a period of 15 to 45 minutes without unpacking, allowing water vapor emanating at least from the shaped rice section to flow in a space formed between the sushi product and the box, thereby steaming the shaped rice section and the sushi material or materials between 10° C. and 30° C.