Enzyme-linked immunosorbent assay kit for the determination of soybean protein in processed foods: interlaboratory...

The labeling of foods containing ingredients derived from soybean is recommended in Japan because of an increasing number of patients who are allergic to soybeans. To ensure proper labeling, a novel sandwich ELISA kit for the determination of soybean protein in processed foods (FASTKIT Ver. II, "Soybean", Nippon Meat Packers, Inc.; "soy kit") has been developed. Five types of incurred samples (model processed foods: rice gruel, sausage, sweet adzuki bean soup, sweet potato cake, and tomato sauce) containing 10 microg soybean soluble protein/g food were prepared for use in interlaboratory evaluations of the soy kit. The soy kit displayed a sufficient RSD(R) value (interlaboratory precision: 9.3-13.4% RSD(R)) and a high level of recovery (97-114%) for all the incurred samples. The RSD(R) value for the incurred samples was mostly < 4.8%. The results of this interlaboratory evaluation suggest that the soy kit can be used as a precise and reliable tool for the determination of soybean proteins in processed foods.