China should set up a national tracking system for agricultural products to pinpoint if they are dangerous or defective, a state report has recommended.

The report, by the National Research Center for Science and Technology for Development, called for a uniform coding system to track produce from the farm to food markets to ensure quality and safety.

Although food-tracking systems have been set up in some cities, they are not standardized and data collected is usually incomplete, the report said.

Only 30 percent of Chinese farm produce meets European or American standards, it said, adding poisonous residue on some farm produce severely exceed safe limits.

A law on farm produce quality and safety, passed by the Standing Committee of the National People's Congress in April, went into effect on November 1.