An organic fertilizer and an organic feed are produced by removing cadmium from processing residues of scallop (Patinopecten yessoensis) without separating the midgut gland. That is, a small amount of an aqueous citric acid solution is added to the processing residues of scallop including the midgut gland in which cadmium has been accumulated at a high concentration and the mixture of them is heated to 55 to 65° C. Thus, the thin midgut gland membrane is broken and the internal solution of the midgut gland containing cadmium is eluted. Then, solid matters are separated from the mixture including the solid matters and the internal solution of the midgut gland eluted. As the aqueous citric acid solution, a solution prepared by mixing at least 9% by weight of water relative to the processing residues and 1.8 to 3.3% by weight of citric acid relative to the total weight of the processing residues and water is used. The content of cadmium in the solid matters can be further reduced by adding water to the solid matters having been separated and then heating the mixture of them to 55 to 65° C., thereby washing off cadmium remaining in the solid matters.
