BEIJING (AP) -- Chinese police have detained 32 people in a nationwide crackdown on ``gutter oil,'' or old kitchen oil that has been illegally recycled, authorities said Tuesday.

The campaign is part of an effort to clean up China's food safety record following several embarrassing scandals, including deadly infant formula and pork tainted with clenbuterol, a banned chemical that makes pork leaner but is harmful to humans.

The Ministry of Public Security said in a statement on its website that police had seized 100 tons (90 metric tons) of the potentially harmful oil in 14 provinces.

It said six workshops were closed, including one operated by Jinan Green Bio Oil Co., a business that claimed to be turning kitchen oil into fuel but that was actually churning out recycled cooking oil that it passed off as new.

Recycled oil can contain carcinogens and traces of aflatoxin, a potentially deadly mold.

``Not only did we destroy a criminal chain that was illegally turning gutter oil into food oil, we also unveiled the greed of the criminals and pulled back the curtain on the immoral acts of those producing this poisonous and harmful food oil,'' the statement said.

It didn't specify what charges the 32 people in detention would face or say when the crackdown started.

Last year, the State Council, China's Cabinet, said businesses that use recycled oil would be forced to close temporarily or lose their business license and that peddlers who sell the oil could be criminally prosecuted.

In recent years, Chinese consumers have been horrified by a series of food safety scandals, including fish treated with cancer-causing antimicrobials, eggs colored with industrial dye and fake liquor that can cause blindness or death. Milk and infant formula laced with the industrial chemical melamine killed six children and sickened 300,000 in 2008.

The government responded by enacting a tough food safety law in 2009 that promised harsh penalties for makers of tainted products.