Detection Rate of Glyphosate Tolerance Gene in Foreign and Domestic Soybeans and Tofu Products

Abstract

The existence of glyphosate tolerance gene was surveyed in 26 soybean samples and 66 tofu products, which were mostly obtained from Tokyo markets from October 1998 to August 1999, using a recently developed PCR method to detect this gene in soybeans. The gene was detected in 2 of 7 American soybean samples and it was not detected in any domestic, Canadian or Chinese soybeans in a total of 19 samples. The two positive American samples were further tested to evaluate the content of genetically modified soybeans by examining 20 individual soybeans. The glyphosate tolerance gene was detected in 9 of 20 IOM soybean grains (45%) and 20 of 20 Roundup Ready soybean grains (100%). Among tofu products, the glyphosate tolerance gene was detected in 2 of 19 kinugoshi tofu samples (10.5%), 6 of 23 momen tofu samples (26.1%), 6 of 12 packed tofu samples (50%) and 2 of 12 other tofu (16.7%).