BEIJING (AP) -- Three senior officials in central China have been suspended and more than two dozen others punished after pigs in farms there tested positive for a banned chemical that can be dangerous to humans, state media said Friday.
Tainted pork has become the latest food safety scandal to shock China after state broadcaster CCTV ran an expose earlier this week showing that several farms in Henan province were using the fat-burning drug, clenbuterol, in pig feed. A subsidiary of the country's largest meat processor was one company pinpointed in the report.
The news prompted an investigation of some pig farms in Henan by provincial inspectors, which Xinhua News Agency said Friday had found that 52 out of about 1,500 pigs in nine farms tested positive for clenbuterol. More inspections are being planned, the report said.
The heads of three animal husbandry bureaus in the province were suspended, Xinhua said, while another 27 were in police custody, sacked or suspended.
The scare has spread to other parts of China. In the eastern city of Nanjing, 264 pigs believed to be from Henan were killed and buried after 20 pigs randomly picked from the group all tested positive for clenbuterol, Xinhua said. Also destroyed were another 1,300 pounds (600 kilograms) of pork at a market, it said.
The Ministry of Commerce said in a statement Friday that authorities have taken measures to block clenbuterol-tainted pork from entering the market, in an apparent bid to ease anxieties in the world's largest producer and consumer of the meat.
Shares of Shuanghui Group, China's largest meat processor, tumbled 10 percent Tuesday after CCTV broadcast the report that mentioned its subsidiary, Jiyuan Shuanghui. The company issued an apology on Wednesday, saying it had ordered the subsidiary to halt operations.
Clenbuterol, known in China simply as "lean meat powder," is banned in China yet stubbornly continues to pop up in the food supply, laced into animal feed by farmers impatient to get their meat to market and turn a profit.
Adding clenbuterol to feed can reduce a pig's body fat to a very thin layer and makes butchered skin pinker, giving the appearance of fresher meat for a longer time. Besides pork, it has also shown up in snake dishes and beef, and people have been hospitalized with stomach pains and diarrhea.
Clenbuterol is believed to be widely used in animal production despite it being banned, underscoring China's chronic problems with policing its food chain.
"It's a symptomatic example of a system that is not delivering the level of safety and confidence in food production that it is supposed to deliver," said Peter Ben Embarek, the World Health Organization's food safety expert in Beijing.
"At least half of animals being raised in China are not slaughtered through formal, supervised slaughterhouse systems but are slaughtered either in farms or in backyard settings, small housings or villages, in uncontrolled environments," he said.
Embarek said humans may suffer symptoms such as a quickened heartbeat and headaches after ingesting clenbuterol and, in rare cases, die.
Pig farmers are often under pressure to use clenbuterol because slaughterhouses would rather buy leaner pigs, said Jason Yan, the U.S. Grains Council's technical director in Beijing.
"The slaughterhouse may pay them higher prices for pigs that looked leaner," Yan said. He added that the majority of large farms in China were unlikely to use drugs like clenbuterol and that the practice was more common in small farms, of which there are many.
In northern Shanxi and Gansu provinces, authorities are strengthening monitoring of pigs and pork supply chains, Xinhua said.
China has been rocked by several food safety scandals in recent years, including tainted milk powder that was linked to the deaths of at least six babies, as well as honey laced with dangerous antimicrobials and eggs dyed with cancer-causing pigments.