On Mr Shen Jianping's antibiotic-free pig farm outside of Shanghai, biosecurity is something of an obsession. Vehicles entering the property are disinfected with a chlorine tyre bath and alcohol spray, animals drink sterilised water and the closest that visitors will get to seeing a live hog is via a TV in the visitors' centre.
The wiry 46-year-old has spent 4.7 million yuan (S$957,000) giving his swine roomier, better-ventilated digs and there are three full-time veterinarians to help keep the 465-sow herd healthy.
"It's like the piglets are now living in a villa that's clean and comfortable," said Mr Shen as he sipped green tea on the patio outside his office. "And it smells much better."
Mr Shen is in the vanguard of a new approach to livestock management in a country that consumes half the planet's pork - and half its infection-fighting medicines.
China's over-reliance on antibiotics in food production places the country at heightened risk of spawning superbugs, genetically evolved bacterial strains resistant to current medicines, that experts fear could trigger a global health crisis.
Antibiotics have been routinely fed to livestock to prevent disease and spur growth in dozens of industrialised countries for decades. However, in China, pig feed typically contains multiple types of bacteria-killing drugs that are used in far greater volumes, said Dr Ying Guangguo, professor of environmental chemistry and ecotoxicology with the Chinese Academy of Sciences in the southern city of Guangzhou.
Drug-resistant infections will lead to one million premature deaths annually in China alone by 2050 and crimp US$20 trillion from the country's potential output without preventive action...
Chinese pigs consume about 19,600 tonnes of antibiotics annually through their feed, scientists estimated in a 2013 study. The average growing pig in China excretes 175 milligrams of antibiotics per day in its urine and faeces, according to Dr Ying's research. He extrapolated that across the nation's entire pig population to estimate that 2,460 tonnes of drugs are released annually. Those chemicals may then leach into water wells and streams, or contaminate manure used to fertilise vegetable fields. Traces have even been found in Shanghai's drinking water and school kids.
This epic outpouring of antibiotic residue in China is a golden opportunity for bacteria, and the genes that the microbes accumulate, to fine-tune their defences and create new superbugs that can evade modern medicines. "It's gene pollution," said Dr Zhu Yongguan, who runs the Institute of Urban Environment within the Chinese Academy of Sciences. "The danger is that these genes can be very mobile. They can be carried by bacteria and the bacteria can travel globally by air travellers, and through the movement of water or commodities."
Mr Shen, the hog farmer, knows his pig feed. Before starting his piggery five years ago, he made and supplied fodder to swine farms near his home town of Tongxiang, 130km from Shanghai.
He worries most about the excessive use of colistin. Developed for humans in the 1950s, doctors quickly stopped using it because it damages the kidneys. That did not prevent its application in poultry and pig farms in Europe, China, Brazil and India.
Now, faced with patients with superbug infections, doctors consider the drug a treatment of last resort. Last November, scientists reported a colistin-resistance gene in China known as mcr-1, which can fortify a dozen or more types of bacteria and has been found in patients, food and environmental samples in at least 20 countries. Four patients have been infected with it in the United States, the Centres for Disease Control and Prevention said this month.
About 11,942 tonnes of colistin, worth US$187.2 million (S$254 million), was used worldwide in 2014, according to Beijing-based QYResearch Medical Research Centre. Of the 10 largest producers of colistin, one is Indian, one is Danish and eight are Chinese, it reported last year.
Pig farmers are largely unaware of the drug's importance or the need to restrict it, Mr Shen said. "Most of them only wish to grow pigs faster."
That rankled him, and he travelled to Belgium and the Netherlands in 2011 to study how farmers there were raising hogs without antibiotics so he could try to replicate their methods back home.
His initial attempt failed. Sixty per cent, or more than 1,000, of his swine died in the first winter. "We didn't know how complicated it would be," he said.
Mr Marc Huon, a pig-management specialist in Belgium, was hired to redesign Mr Shen's pigsty. The first priority, Mr Huon said, was to give each pig more space, better ventilation and to remove stress on the animals caused by temperature fluctuations. He also recommended a higher-protein diet based on a broader range of nutrients and the addition of supplements, including prebiotics to promote helpful intestinal bacteria in the pigs.
Water piped into the temperature-controlled barn has been filtered and purified with charcoal, and heated and irradiated to remove pathogens. "The water our pigs drink is better than the tap water in Shanghai," Mr Shen said. These days, mortality is 5 to 6 per cent-much less than the 15 to 16 per cent average in neighbouring piggeries.
It takes Mr Shen's pigs about eight months to reach the 115kg to 135kg target weight for slaughter. That is four to five weeks longer than pigs fed antibiotics and other growth promoters, according to Mr Huon. The Belgian's nutrition plan emphasises meat quality over weight gain. "It's just a copy and paste of what we are doing here,'' he said over the telephone from Belgium.
The Netherlands and Belgium have been reducing the use of antimicrobial drugs on farms for years, following Denmark's lead in banning the non-therapeutic use of antibiotics in pigs in 1999.
The antibiotic-free status of Mr Shen's meat is validated by an independent auditor. The farmer said he has thought about going organic, but says it is too difficult to source fully organic fodder. As it is, antibiotics are used only to treat sick pigs, with the meat from those animals sold separately to local butchers. A QR code on the pack of every antibiotic-free product Mr Shen sells enables shoppers to view real-time images of his piggery using their smartphones.
"I explained to Shen four years ago that this would be a good solution for him to distinguish himself from the others," Mr Huon said. "Today, the biggest problem is that farmers only think about money."
PRESSURE TO ACT
That said, there is a growing public awareness of food production safety, said Dr Ying, who has published more than 100 papers on antibiotic emissions and environmental contamination in China. "Ordinary people are very worried nowadays because of media reports," he said. "There is big pressure to do something.''
Farmers, too, have reason to be alarmed. A study published this month based on rectal swabs from pigs in the eastern province of Shandong and farm workers raising them found that more than half of the swine carried a particular super-resistant E. coli known as ESBL that was also present in a fifth of the farm workers. Some of the germs were genetically identical, indicating pigs were the likely source.
When the rotting carcasses of more than 16,000 pigs - some of which were reportedly diseased - were found in early 2013 in the tributaries of the main river running through Shanghai, threatening the region's water supply, the authorities acted quickly.
Millions of small piggeries were closed in a nationwide rationalisation programme aimed at shifting pork production to larger, more efficient farms. It resulted in one of the largest culls in history - a reduction in hog numbers equivalent to the disappearance of the US, Canadian and Mexican pork industries from global supply in less than two years, according to Rabobank Groep.
Around Tongxiang, where Mr Shen lives, there were about 3,000 piggeries, mostly raising fewer than 100 pigs, before the closures. He counts about 50 now.
Drug-resistant infections will lead to one million premature deaths annually in China alone by 2050 and crimp US$20 trillion from the country's potential output without preventive action, according to research on antimicrobial resistance prepared by a team led by Lord Jim O'Neill, the British economist who coined the acronym Bric for Brazil, Russia, India and China.
The World Bank last Monday said antimicrobial resistance would cause annual global gross domestic product to fall 1.1 per cent to 3.8 per cent by 2050, raise annual healthcare costs by as much as US$1 trillion, and lead to a 2.6 to 7.5 per cent a year decline in livestock production.
Leaders of the Group of 20, who met this month in Hangzhou, China, pledged to promote the prudent use of antibiotics, and affirmed the need to fight resistance, including through supporting drug research.
At the United Nations in New York last Wednesday, world leaders discussed a global response, including tackling the irrational human and veterinary use of antibiotics and how to support efforts in developing countries.
"The problem is extensive and it may be speeding upwards quickly, but it's also clear that we now have a level of attention that we have never had before," said Mr Keiji Fukuda, the World Health Organisation's special representative on antimicrobial resistance, in a telephone interview from Geneva. "We have to push that and use that as much as possible."
CHILDREN'S HEALTH RIGHTS
In Shanghai and urban areas of surrounding Jiangsu and Zhejiang provinces, a study of urine samples from more than 1,000 primary school-age children found four out of five specimens harboured one or more antibiotics. Twenty-one different antibiotics were detected, including among children who had not been treated with the medicines for several years.
Authors of the study, published last year in the journal Environmental Science & Technology, blamed the antibiotic contamination of food and the environment, caused by the misuse of the drugs, which they said may be associated with inflammatory bowel disease, childhood asthma, obesity and tumours. "Therefore, the elimination of water pollutants is one of the hot spots of scientific research," the study's 13 authors wrote.
China's government released a national action plan last month to tackle antimicrobial resistance. Among goals for the next five years is to phase out the use of important antibiotics on farms as growth promoters and to strengthen the oversight and control of their sale in veterinary medicine.
"Antimicrobial resistance is not only a problem that exists in our country, but also a major challenge facing the global public health field," said Mr Ma Xiaowei, deputy head of China's National Health and Family Planning Commission.
His comments were posted on the commission's website in April from a meeting where 12 government departments discussed the action plan. Mitigating the risk "is a necessary requirement to protect the health rights of the people" and help China reach its goal of being a prosperous society while showing that it is a responsible major power, he said.
The Health Ministry in June released dietary guidelines that recommend citizens reduce meat consumption by half.
The prospect of a decline in meat consumption is not deterring Mr Shen, who plans to increase his annual output by 50 per cent to 15,000 head this year and 50,000 in three years. He is scouting for land around Beijing and in the southern province of Guangdong to establish other antibiotic-free piggeries. "Chinese people want safe and reliable food, but they can't often find it," he said.
Mr Shen's antibiotic-free pork is sold through retail outlets locally in Jiaxing City and via e-commerce sites, including Alibaba, under the Tongxiang label. Priced at about 70 yuan a kilogram, it is almost twice as expensive as regular pork, which sells for about 40 yuan a kilogram. His pig livers command 10 times the going rate.
"In the past, nobody would buy such expensive pork," he said. "Now, kids are more likely to get sick and people are increasingly aware of the impact of antibiotics."
Dr Zhu believes that one promising approach in controlling the spread of antibiotic resistance genes involves removing them from animal excrement while preserving the manure's nutrient content so that it can be safely used as fertiliser. He has worked with Mr Shen to filter bacteria and other unwanted residues from animal waste using membrane technology, then ultra-heat-treating the solids to produce bio-char, which Mr Shen sells in bags at the visitor centre on his farm.
"We are developing technologies for sustainable intensive animal farming," Dr Zhu said. "If you sterilise the pig manure to remove the bacteria, you can reduce the risk dramatically."
Mr Shen, meanwhile, thinks it is crucial to educate kindergarten children about the effects of antibiotics in the food system. His farm hosts two or three tours a week and invites students to make dumplings from his pork and watch a demonstration of how differently his pig livers look after cooking, compared with those from swine raised on antibiotics. "We let them taste pork from us and from others," he said. "Chinese kids will see a big health problem if nothing changes."