Besides shells, about eighty to ninety thousand tons of underutilized scallop byproducts (i. e. digestive glands, mantles, gonads, etc.) are discarded in Hokkaido. To utilize the scallop waste, we investigated the manufacturing process of scallop meal, which would be used as a fertilizer or feed.

The scallop、waste contains a considerable amount of cadmium. Hokkaido Industrial Research lnstitute had developed a removal method for cadmium using dilute sulfuric acid. To prevent the oxidization of the fat, scallop waste should be sealed and preserved in the freezer for use as feed. When the scallop waste was processed into fertilizer, it could be temporarily preserved at temporarily at room in the dilute sulfuric acid.

The dehydration and defatting process v/as compared using a screwpress and an extruder. With the extruder, dehydration and defatting efficiencies were better than those with the screwpress. Either boiling and mashing the scallop waste before screwpress processing, or heating the axis of the screwpress had improved efficiencies of dehydration and defatting significantly.

We also analyzed the dried scallop meal after removal of cadmium, excess water, and excess fat.

It had an acceptable quality as a fertilizer, but it needed to be mixed with other materials, which contained less fat, for use as feed.

Since scallop meal contains considerable amounts of unsaturated fatty acid, a low cost preserving method for the scallop meal, that prevents oxidization, should be developed.