Packs of chicken feet smuggled into the country to be processed and sold in south China were over 40 years old, police said yesterday.

Nanning police said they recently confiscated more than 20 tons of expired chicken feet along with cows' stomachs, throats and other animal organs, also out of date, in the capital city of south China's Guangxi Zhuang Autonomous Region.

The oldest packs of frozen chicken feet were labelled as being produced in 1967, Xinhua news agency reported.

"These raw materials were smuggled from neighboring countries and smugglers would soak them in toxic chemical solutions to remove the blood and smell and sell them on to markets," police said.

According to Xinhua, there is a massive trade in chicken feet and other animal parts from foreign countries, including the United States and the UK, to Chinese cities because these animal parts are popular in China but regarded as waste in most foreign countries. Some trade is legitimate, Xinhua said, but much of it is illegal, with smugglers hiding frozen animal parts among fruit or lumber destined for China.

Over the past year, frontier police in Guangxi said they had cracked seven major smuggling cases involving chicken feet with the total value of over 20 million yuan (US$3.26 million).

Police official Li Jianmin told Xinhua that most of the frozen chicken feet was of poor quality but smugglers would soak them in hydrogen dioxide or bleaching powder to make the feet look whiter and bigger.

Li said a kilogram of chicken feet would become 1.5 kilograms after being soaked in the solution.

He said that the workshops they raided were so dirty and foul-smelling that people could only stay inside them for a few minutes at a time.

Hydrogen dioxide is banned from use in food processing in China and Li said the sewage from the workshops had killed fish in a nearby pond.

He said there were huge profits to be made from the illegal trade. Smugglers could buy a ton of chicken feet for about 5,000 yuan from foreign sellers, but sell them at four times that amount after defrosting, processing and packing.

The processed chicken feet and other animal parts were normally sold to small restaurants and outdoor barbecue owners.

Li said it was a difficult task for the police to crack down on the trade because smugglers would collaborate with some courier companies to transport the products hidden in other cargo.

When drivers were questioned they would tell police that they had no idea what cargo they were carrying, he said.

"So it would be difficult for police to find the smugglers without tip-offs," he added.

Meanwhile, some 141 smuggled bear paws had been found in the region over the past year, said Luo Weidong, director of the Guangxi forest police station.

Although they had started to smell during transport, the bear paws would be sold to restaurants where chefs would use additives to transform them into expensive dishes, Luo said.