More than 900 arrested in China over meat contamination, including fox, rat, and mink passed off as mutton

Chinese police have arrested 904 people and seized 20,000 tonnes of illegal products since the turn of the year, in an investigation into "meat-related offences" which revealed fox, mink and rat meat all being passed off as mutton.

Suspects in Baotou produced fake beef and lamb jerky from duck meat and sold it to markets in 15 provinces. Levels of E coli in the product "seriously exceeded standards", the country's Public Security Ministry said.

One suspect, called Wei, made more than $1 million (£643,000) over four years buying fox, mink and rat meat, adding gelatin and other additives, then selling it as mutton at farmers' markets in Jiangsu province and Shanghai. Authorities raided Wei's organisation in February, arresting 63 suspects and seizing 10 tonnes of meat and additives.

Hao, another suspect, from Fengxiang city, Shaanxi province, last year sold mutton that had turned black and reeked of agricultural chemicals to a barbecue restaurant, killing one customer and poisoning a handful of others.

Some have been arrested for chopping up diseased pig carcasses to sell on, despite having been paid by the government to collect the bodies from farmers for proper disposal. Others, in the south-western province of Guizhou, soaked chicken feet in hydrogen peroxide before shipping them to markets, and in Zhenjiang city, Jiangsu province, two people were arrested for selling pork products that were made with meat from "poor quality pig heads".

China's meat market is no stranger to contamination scares. In March, pork sales plummeted after about 16,000 pig carcasses were dredged from a river in Shanghai, an incident authorities have yet to fully explain. And a strain of avian flu has killed 26 people and put more than 129 in hospital since mid-April.

New guidelines calling for harsher penalties for those found guilty of producing or selling unsafe food products were announced by the country's top court on Friday.

The supreme people's court said the guidelines would list as crimes acts such as the sale of food excessively treated with chemicals or made from animals that have died from disease or unknown causes.

Other food safety scandals in recent years include reports of glow-in-the-dark pork, exploding watermelons, cadmium-laced rice, fake eggs and salmonella-tainted seafood.