SHANGHAI, Sept. 15 (Xinhua) -- More than 300 people in Shanghai appear to have been poisoned by pork containing an animal-feed additive, sources with the municipal health authorities announced on Friday afternoon.

A total of 278 people were hospitalized in the Pudong New Area but most of them have now been discharged from five local hospitals, said officials with the New Area's food and drug supervision bureau. Only around a dozen people remain in hospital for further observation.

The patients' symptoms - dizziness, fatigue, racing pulse and muscular tremors - resemble the symptoms for poisoning by clenbuterol, a dangerous animal-feed additive, said Zhu Changqing, head of the emergency department of Renjin Hospital in the Pudong New Area.

The feed additive, dubbed "Shouroujing", in Chinese literately means lean meat essence for pigs. It is used to prevent pigs from accumulating fat.

The ill people reported they ate pork, pig liver and other pig organs, and 128 of them had lunch at their work unit canteen before developing the symptoms.

The Pudong food and drug supervision bureau said blood samples have been collected from the patients for testing. Results will come out in three days.

China has banned the use of "Shouroujing" as an additive in pigfeed. The chemical poisons human beings and can be fatal. Enditem