Determination of the geographic origin and the cultivation method of dried shiitake mushroom by inorganic analysis

The amount of imported of dried Shiitake (Lentinula edodes) mushrooms is twice that of Japanese production, with most imports coming from China. While all domestic cultivation occurs on logs, Chinese mushrooms are cultivated chiefly on sawdust-based medium. The Japan Agricultural Standard (JAS) law requires the correct labeling for both geographic origin and whether the cultivation method used log (GENBOKU) or sawdust-based medium (KINSHYOU) of dried Shiitake mushroom. We developed a method for determining whether dried Shiitake mushrooms originate in Japan or in China by quantifying 29 elements contained in 147 training samples. A linear discriminant analysis (LDA) model calibrated with concentrations of 5 elements (P, Cu, Zn, Mo and La) from 97 GENBOKU and 50 KINSHYOU samples, assigned the correct cultivation characteristics to 60 test samples with 100% certainty. An LDA model calibrated using the concentrations of 9 elements (Li, Mg, At, Ca, Mn, Co, Me, Cd and Ce) from 50 Japanese GENBOKU and 47 Chinese GENBOKU samples, correctly predicted 45 test samples with 93% certainty. In addition, the LDA model for a 3-group-classification, calibrated using the concentrations of 13 elements (P, Pb, Zn, Me, La, Li, Mg, Al, Na, Mn, Co, Mo, Cd and Ce) from 50 Japanese GENBOKU, 47 Chinese GENBOKU and 50 Chinese KINSHYOU samples, correctly predicted the origin and type of 60 test samples with 93% certainty. It was demonstrated that the assignment of geographic origin and cultivation method of dried Shiitake could be accurately authenticated by this method.