07 February 2019- As African Swine Fever continues to preoccupy the world’s pig producers, the threat posed by swill feeding has increasingly come into focus.

Table scraps have traditionally made up part of pigs’ diets in many parts of the world, and in areas where informal backyard production continues at a significant level, it poses a transmission risk for disease.

According to information cited by the FAO, 62% of the first 21 ASF events in China were related to swill feeding, which has caused the country to ban the practice nationwide. “Swill feeding practices are considered one of the major risks for the introduction and spread of the virus,” claims the OIE’s regional representation body for Asia and the Pacific.

The virus’s history of spreading in this way makes the circulation of contaminated meat products a serious biosecurity threat, even if ASF does not sicken humans. Meat testing positive for the virus has been intercepted on its way into Australia, South Korea, Thailand, Japan, and Taiwan, in many cases brought by individual travellers and identified at airports in the form of processed meats such as sausages.

Major pig producers across Asia-Pacific have different policies concerning swill feeding. Australia, for example, bans the practice of feeding food waste that has come into contact with meat products. Contrarily, other Pacific Rim countries have encouraged or institutionalized swill feeding, establishing formal channels through which catering and retail waste should pass; in many, but not all jurisdictions, food wastes must be re-cooked to kill viruses before being fed to animals. Japan, South Korea, Taiwan, and possibly Thailand are among the countries using food waste for feed on industrial scales.

Across the Pacific, American policy on the issue of what they call “garbage feeding” is handled at state level, with over half allowing the feeding of heat-treated food waste to pigs, although not every state in which the practice is legal has a licensed garbage feeder; meanwhile, as of 2016, nearly all states allowed individual (non-commercial) hog owners to feed their own animals on household food scraps.

The spread of ASF to such a key country in the agricultural supply chain has caused some scrutiny of this practice. In Taiwan, the important swine-producing county of Yunlin banned swill feeding in December.

However, given that space is at a premium on the small, densely-populated island, the central Taiwanese government has proven loathe to ban a practice which is used to divert a significant portion of the food waste generated on the island away from landfills, although it is understood that authorities are encouraging a move away from the practice and towards commercial feed, and have also recently enacted rules requiring anyone who wants to use food waste as feed to boil the waste first.

Similarly, South Korea is reported to be stepping up inspections to ensure untreated food waste is not fed to pigs.

Even countries where the practice of feeding food waste is not as formalized are looking for ways to curb the risks it poses. In the Philippines, for example, the government has banned the use of food waste specifically from international ports from being used as swill feed for pigs since the end of August 2018, as well as banning imported pork from any country where ASF has been identified. At a local level, the Davao Backyard Swine Raisers Association is launching an information campaign about the dangers of the disease, even going so far as to construct a feed mill for small producers to provide alternatives to swill feed. Such initiatives are especially important given the extent of informal pig production in the country; Philippine press source BusinessWorld claims around 64% of the country’s swine is from backyard producers.

It seems likely, therefore, that food waste from both informal and institutional channels will continue to find its way into the rations of swine in the Asia-Pacific region, in spite of its dangers. This makes other risk control techniques even more important. For one thing, it underlines the importance of controlling the circulation of pigs and pork products in areas where the virus is known to have established itself. This is something that China has attempted in September, shutting down transport of live pigs across the borders of provinces affected with the disease. However, the side effect of this has been to create supply/demand imbalances and severely disrupt supply chains, as much of the country’s swine production takes place in the hinterlands while slaughter—and indeed consumption—takes place closer to populated areas, and it is understood that the interregional transport prohibitions began to relax slightly over a month ago in preparation for the Chinese festive season.