Three Chinese farmers were held for operating an illegal pork business selling meat from pigs that died of disease, state media said Monday, the latest in a series of food scandals to hit China.

The farmers were contracted to dispose of dead swine on a farm in the southeastern province of Fujian but instead sold the meat for human consumption, the Global Times newspaper said.

More than 40 tonnes were sold, worth some three million yuan ($490,000), the newspaper added.

Animal disease investigators found a "pseudo-rabies virus" -- which is related to the herpes virus, rather than rabies -- and also the virus that causes blue ear disease, "which likely killed the pigs", the report said.

"Both viruses are highly contagious and fatal to the animals," it added, without specifying how many swine were infected or whether some died from other causes.

A truck driver and guard drafted in by the trio are also facing charges, according to a statement from the ministry of public security. Three butchers hired to process the meat remain at large, the Global Times report said.

Food safety is a major issue in China following a string of scandals, including the discovery in March of thousands of dead pigs floating down a Shanghai river.

In another recent incident, US fast food giant KFC was hit by controversy after revealing some Chinese suppliers provided chicken with high levels of antibiotics, in what appeared to be an industry-wide practice.

The use of "gutter oil" is a perennial food safety issue, where cheap recycled cooking oil is made illegally from leftovers and material scooped out of restaurant drains.

One of China's worst food scandals hit in 2008 when the industrial chemical melamine was found to have been illegally added to dairy products, killing at least six babies and making 300,000 people ill.