An initial investigation has found that 12 government officials were implicated in a scandal involving tarnished meat products, while another 41 are still being probed.

An animal health professional enters a pigpen in Nanyang, Henan province, on March 24 to get urine samples to test for clenbuterol. [Photo: China Daily]

In an announcement on Monday, the Henan provincial government said law enforcement officers have captured two major suspects and shut down their plants, after they tested 310,000 pigs across the province and confirmed that 134 of them tested positive for clenbuterol, a toxic chemical added to the animal's feed.

The 12 officials have been delivered to judicial departments for further investigation, the government said.

The scandal, dating back to March 15 when China Central Television reported Jiyuan Shuanghui Food Co Ltd, a supplier of the country's largest meat processor -- Henan-based Shuanghui company -- had purchased pigs fed with the illegal additive.

The report said the massive flow of tarnished meat into the market was partially due to local quarantine officials who allow pig farmers to choose the test samples by themselves.

Clenbuterol, which is also known as "lean meat powder", can accelerate muscle-building resulting in leaner pork.

An earlier raid put 14 farm managers and brokers in custody and at least 27 local officials were fired or suspended, the local government said.

However, Liu Mancang, vice-governor of the province, said the scandal has caused disastrous effects and the government will introduce tighter measures to completely secure food safety.