BEIJING - Last month, more than 16,000 dead pigs were found in tributaries of the Huangpu River, not far from Shanghai, in eastern China.

At the same time, scores of diseased pig carcasses were also found miles away in Liuyang River, in the south-central Hunan Province. The massive number of dead pigs discovered nationwide caused great public concern.

According to the National Bureau of Statistics, China supplied the market with 700 million pigs in 2012. That’s about half the pig production of the world. Even with a conservative estimate of a natural mortality rate of 3 to 5%, that means 18 to 35 million pigs die of disease every year. Disposing of these carcasses is not a simple affair.

In theory the Chinese government has come up with a sanitary way for farmers to decontaminate and dispose of these carcasses. Diseased animals have to be buried at least 1,5 meters deep or cremated. Farmers can apply to receive a subsidy of 80 Yuan ($12) for each diseased pig they dispose of in this way. 

But in practice, dead pig carcasses are most often thrown into rivers or dumped somewhere. A large number of them are sold on the black market, and end up on people’s plates. 

Our knowledge of this phenomenon is based on numerous investigative news reports, court reports, and academic studies. However it is little known that dead livestock or poultry can have serious public health consequences.

According to Xie Yan, an associate researcher at the Institute of Zoology of the Chinese Academy of Sciences, the illegal disposal of dead animals is bound to pose a threat to the environment and to public safety. For instance, a virus that is originally only found in animals can come into close contact with humans –leading to zoonosis, where an infectious disease is transmitted from animals to human. The most obvious examples of such a transmission are the SARS virus and bird flu. Dead pigs spreading infectious diseases are in our near future.

In 2005, Sichuan Province, in southwest China, reported 215 human cases of Streptococcus suis, with 38 deaths. Subsequent investigations showed that the outbreak was caused by diseased pigs sold on the black market. All the deceased had been in contact with the pigs, from either slaughtering, processing or eating them.

In 1997, after the outbreak of foot-and-mouth disease in Taiwan, the World Organization for Animal Health (OIE) issued a 10-year ban on the export of Taiwanese pork and pork products. The epidemic had been caused by pig carcasses discarded in a roadside ditch.

What is particularly worrying in China is that the sanitary disposal of animal carcasses is not a priority – although it should be. The existing system has a lot of loopholes, and a new more realistic and practical system has yet to be introduced. 

Although China is the world's biggest pig breeding country, it lags behind in carcass disposal standards and related subsidies to farmers.

Major obstacles

At the end of 2009, the Chinese government introduced regulation standards on how to process diseased animals and diseased animal products. This includes the aforementioned burying carcasses 1,5 meters deep or cremating them and farmers being eligible for a subsidy for each carcass they dispose of this way. But this hasn’t helped control the anarchic way farmers dispose of animal carcasses. Based on our investigations, there are three major obstacles preventing farmers from conforming to disposal standards.

First, farms with less than 50 pigs are excluded from receiving subsidies for disposing of pig carcasses. Yet, according to the National Bureau of Statistics, one third of China’s farms – representing 220 million pigs – have less than 50 pigs each. Using the 5% natural mortality rate, that is 11 million dead pigs per year that aren’t eligible for subsidies. A number that can rise much higher in the case of a disease outbreak.

Second, the subsidy is far too low. The cost of incinerating is both costly and technically complex – and thus not very practical for a small farm. Even deep burial, which is the most practiced disposal method costs much more than 80 Yuan per pig. It is estimated that the process of digging a pit, transporting and disinfecting a carcass according to regulatory standards is at least about 160 Yuan ($26) for an adult pig, half that for a piglet.

Third, according to the market price of pork, the death of a pig costs the farmer between 1120 ($180) to 1400 Yuan ($226). Added to the cost of disposing the carcass according to standards, and it’s understandably not worthwhile for farmers.

Meanwhile those who enforce these regulations are overwhelmed and unable to regulate efficiently. They are also tasked with epidemic prevention, quarantine and offering farmers technical advice and guidance. The resulting anarchy leads to infected pork ending up in the plates of Chinese citizens.

In our investigations in Chinese pig producing regions, we found that many farmers sold their dead pigs on the black market – where they could get between 2 (30 cents) and  6 Yuan ($1) per kilogram.

Xinhua news agency reported that the Chinese Ministry of Public Security launched in March 2012 a campaign against food with banned additives, illegal cooking oil, “unfresh” pork and counterfeit drugs as part of a “dinner table safety” initiative. Between 2011 and March 2012, local health officials uncovered 170 cases involving 6,000 tons of “unfresh” pork.

Meanwhile, few people know that illegally disposing of diseased carcasses is very common. Regulation standards stipulate that carcasses must be buried deep, far away from schools, public areas, residential areas, villages, animal breeding areas and slaughterhouses, drinking water sources, rivers and etc. According to a survey of 150 farms in Jiangsu Province, eastern China, in 142 cases, diseased pig carcasses were disposed of in very shallow pits without being disinfected, covered in only a thin layer of soil. Most often they were just a few meters away from ponds and rivers.

From trash to treasure

It is not all bad news. In recent years certain regions have started to turn the dead pigs from trash to treasure.

For instance, when Zhu Fangmin of Suining County, Jiangsu Province, found out in 2011 that each year about 6,000 diseased pigs die in his county, he asked himself how he could turn this grim statistic into a profit. He invested nearly one million Yuan ($160,000) to set up a carcass treatment plant in his village. The dead livestock goes through a series of treatments including high-temperature and high-pressure processing to exterminate pathogens carried by the dead animals and is turned into industrial oil or fertilizer.

The plant can dispose of 150 to 200 dead pigs every day, earning Zhu more than 100,000 Yuan ($16,200) in profit in 2012 and enabling local farmers to get a compensation of 1000 Yuan ($162) for each pig they bring into the plant.

In comparison to selling infected pigs to unscrupulous businessmen for 100 ($16) to 200 Yuan ($32), this scheme is much more motivating for farmers.

Taiwan, which is also a big pork producer, no longer has the same problem with carcass disposal. Before the foot-and-mouth disease outbreak, carcass disposal was not monitored. But when the outbreak occurred, almost four million pigs were destroyed and had to be buried, posing a huge risk to public safety. Thanks to persistent research, Taiwan came up with a system where 80% of its diseased pig carcasses are now processed into industrial oil and fertilizer.

Moreover the Taiwanese government grants a subsidy of more than 60% of the cost of building a carcass processing plant.

Another difference with China is that in Taiwanese pigs are all insured, which means that farmers are covered in case their pigs die. Taiwan has also set up an extensive monitoring system, where all pigs and pig farms are registered and subject to meticulous controls.