The head of one of China's largest meat processing companies has been receiving special reports via text message every morning for the last two years.

The messages are brief quarantine reports of his company's products, including how many pigs were found infected with a disease or had excessive levels of fodder additives, said Wan Long, chairman of Shuanghui Group.

"Of the 170,270 pigs purchased on March 5, 29 were found to have disease and none had clenbuterol," read a text he received on March 6.

Wan, 73, a deputy to the National People's Congress, said the company attached more importance to food safety after it was found to have sold chemically tainted products two years ago.

In March 2011, China Central Television reported that Shuanghui Group had bought pigs that had been fed fodder containing clenbuterol, a harmful additive known as "lean meat powder" because it can promote lean meat growth in livestock.

In 2002, the central government banned the use of lean meat powder, such as ractopamine and clenbuterol, in feed additives and drinking water for livestock.

The scandal aroused public concern on food safety again, coming as it did not long after Sanlu Group was found to have sold melamine-tainted milk in 2008. The contaminated milk killed six infants and poisoned more than 300,000 others.

Shuanghui Group's sales slumped immediately after its own contamination scandal, causing an economic loss of 1.5 billion yuan ($241 million) from March 16 to 31, 2011, Wan said.

Police detained 96 people, including the producers, sellers and buyers of the banned additive, the following April. Three workers from Shuanghui Group's purchasing department were among them.

Wan made two public apologies and vowed to take tougher quarantine measures to guarantee food safety.

Today, instead of making sample tests, the company requires every newly purchased pig to be checked for diseases and food-additive levels.

"Testing each pig costs more than 100 million yuan a year, but it shows a more responsible attitude to the health of our consumers," Wan said.

To regain consumer trust, Shuanghui Group invited the public to visit its factories and has made its production process more transparent.

The company buys pigs from large farms rather than small operations, which decreases the risk of buying pigs that fail to meet standards, Wan said.