The Ministry of Agriculture on Monday released the results of an investigation into contaminated fish, saying sales of the fish had been banned, stocks destroyed and producers punished.

Shanghai health authorities announced on Nov. 17 they had detected excessive residues of carcinogenic chemicals nitrofuran and chloromycetin in 30 samples of turbot.

Several cities and provinces -- including Beijing, Tianjin, Xi'an and Liaoning -- started quality inspections of turbot, and many banned the sales of turbot, most of it provided by three fishery enterprises in eastern China's Shandong Province.

A Ministry of Agriculture statement said an inspection team was sent to Shandong, where nitrofuran and chloromycetin were found in the fish farms.

Nitrofuran and chloromycetin are man-made substances that have been prohibited for fish feed under Chinese law, the ministry said.

The three enterprises in Shandong had been banned from selling fish products and fined, said Zhang Yuxiang, chief economist with the ministry.

The ministry would continue its investigation to trace the source of the chemicals, Zhang said.

Due to its low resistance to disease, the turbot, introduced from Europe in the 1990s, is sometimes fed large quantities of medicinal supplements that leave potentially harmful residues in the flesh.

Source: Xinhua