To reduce acid taste of citric acid because the citric acid has so strong the acid taste that the citric acid is hardly ingested directly so that a body may become neutral or weak alkali by the citric acid cycle to reduce fatigue, because one cause of damaging the health is acidification of the body caused by eating habits, and further to allow the nutritive value of an egg shell and a shell membrane to be ingested so that the health may be promoted by ingesting the powder of the egg shell and the shell membrane.

This processed food is obtained by sufficiently stirring citric acid with a powder egg shell and shell membrane, in a ratio of 1:1, and naturally drying the obtained mixture so as to be readily ingested without acid taste. Because the components of the powder of the egg shell and the shell membrane are deteriorated in a moist atmosphere or at a high temperature of ≥65°C, the processed food is separately packed by a multi-laminated film of aluminum to prevent the deterioration of the components and to prevent the quality of the processed food from being changed.