American soybeans exported to China failed to meet national quality standards, the Wall Street Journal reported. US-imported soybeans are often contaminated with harmful weeds and soybean disease, and one shipment in February was tainted with pesticides, said the General Administration of Quality Supervision, Inspection and Quarantine (GAQSIQ), China's product safety watchdog. GAQSIQ said it would strengthen supervision and inspection of soybean imports, and has requested that an investigation be carried out in the US. The complaint is the latest in a series of product recalls, customs seizures and official statements exchanged between China and its major trading partners, including the US and the European Union, regarding food and product safety.