A butcher chops pork at a market in Shanghai, China on May 30, 2013.

At an age when most Chinese executives are long retired, the country's top hog butcher is taking on a daunting new job persuading Americans to allow him to complete China's biggest takeover of a U.S. company.

Shuanghui International's $4.7 billion bid for Smithfield Foods has the endorsement of the American company's board. But facing anxiety over food safety scandals in China and complaints about Chinese cyber spying, 72-year-old chairman Wan Long has launched a charm offensive to reassure Americans they have nothing to fear and possibly much to gain from the tie-up.