To increase the market niche for scallop-based food products, we developed a high-quality scallop flake food and a new type of fermented sushi using boiled scallop ( izushi ). Scallop flake food comprises heated adductor muscles that are shredded into coarse fibers. Scallop flake food is a useful material for various culinary preparations, and its processing method is quite simple. Such foods are expected to become popular. In the present study, conditions for thawing frozen adductor muscle, heating adductor muscle, breaking up adductor muscle fibers, and sterilizing scallop flake food were improved. We finally established a processing method for high-quality scallop flake food. Izushi is one of the traditional fermented foods consumed in the Hokkaido and Tohoku districts. However, izushi made from scallop adductor muscle has not yet been developed. One of the reasons for this is that the weak texture and taste of scallop adductor muscle are not considered suitable for izushi preparation. We therefore investigated conditions for pickling and adjusting the weight of scallop adductor muscle during the fermentation process, and found ways to improve both the texture and taste of izushi. Our innovative processes will enable novel, marketable food products based on scallop adductor muscle.