The 6,000 rotting pigs floating toward Shanghai may pose a public health problem, but at least they are not part of a much greater threat. If they had not been thrown into the Huangpu River, it is emerging, they might well have ended up on dinner plates.

The discovery of the dead pigs has thrown a spotlight on a little-known practice that insiders say is not uncommon in China: Farmers sell pigs that have died from disease to underground traders, who then sell the pork illegally to consumers and food processing firms.

On Wednesday, 46 men were jailed in Wenling, in the eastern province of Zhejiang, for selling meat from sick pigs. Wenling is not far from Jiaxing, another hog-rearing district whence officials say the pigs found in the Huangpu are believed to have come.

In the past two years at least six other similar cases have come to court in different parts of China, suggesting that the practice is widespread.

“The pig mortality rate is high and farmers sell the carcasses to people in the illegal business so as to recoup some of their losses,” says Feng Yonghui, an analyst with Zhongkeyiheng, an agri-business consultancy in Beijing.

“Big cities supervise the animal trade strictly, so the sale of sick corpses is not common in Shanghai,” adds Lin Rongquan, a retired veterinarian who advises the Shanghai government on food safety issues. “But it happens in smaller cities because supervision departments don’t always do their job properly.”

The Zhejiang police announced on their website that they had launched a crackdown earlier this year on the illegal pork business. “Since the police stepped up their efforts ... nobody has come here to buy dead pigs and the problem of pig dumping is worse than ever this year,” one pig farmer was quoted as saying in the Jiaxing Daily, a newspaper run by the local government.

Pork is a staple food in China, which has the largest porcine population in the world. Its 475 million pigs represent nearly half the global total.

Some 70 percent of these animals are raised by small farmers, and mortality rates are high. In the town of Jiaxing alone nearly 750,000 pigs die of disease every year, estimates Mr. Lin.

By law, these carcasses should be either buried or cremated, but the temptation to bypass the law by selling or dumping them is strong for small farmers who are working to tight profit margins.

For a start, says Lin, “these individual farmers have little sensitivity to official regulations.” At the same time, Mr. Feng points out, digging deep burial holes is tiresome “and lots of farmers don’t have enough land to dig holes anyway.”

Cremation, meanwhile, is expensive and not always feasible. In Jiaxing, for example, all the cremation centers were reported to have been working at full capacity following a cold spell that killed an unusual number of piglets last month.

And though the Ministry of Agriculture regulations set generous rates of compensation for cremated animals, “in real life the money takes a long time to come through if it ever comes at all,” says Feng, “because nobody ensures that the law is enforced.” The result, he adds, is that farmers often do not bother to take their carcasses for official cremation.

Get the Monitor Stories you care about delivered to your inbox. By signing up, you agree to our Privacy Policy

Though the rules on how dead animals should be disposed of are strict, agrees Lin, incidents such as the recent appearance of thousands of pigs in the Huangpu reveal official incompetence.

“The local authorities are meant to know how many pigs are being reared in their district and how many have died, but they are not saying anything because they do not want to take responsibility” for the scandal, says Lin. “They did not do their job properly.”