The Shanghai Food and Drug Administration promised yesterday to tighten local inspections of edible oil after spot-checks in Taiwan at popular fast-food outlets such as McDonald's, KFC and Domino's Pizza found arsenic and a compound that's been linked to cancer in animal studies.

Arsenic was detected at two McDonald's and a Domino's, and acrylamide, a chemical compound that forms when certain carbohydrate-rich foods are fried, baked or roasted at high temperatures, was found at seven restaurants. The checks were carried out at three McDonald's, two KFCs, one Domino's and one Napoli pizza shop in Taiwan.

Shanghai's FDA said it had checked 185 samples of edible oils from local supermarkets and restaurants since 2008 and hadn't found any arsenic, though the inspections didn't include McDonald's or KFC.

"We have been on high alert after the arsenic issue surfaced in Taiwan and will broaden our inspections to enhance supervision," Gu Zhenhua, director of the Shanghai FDA's department of food inspection, said yesterday.

He said inorganic arsenic exists widely in the environment. The maximum content for inorganic arsenic in food is usually 0.1 to 0.5 parts per million, depending on the type of product.

The Taipei County government reported on Tuesday that its checks found arsenic in the oil at two McDonald's outlets to be 0.92 ppm and 1.038 ppm, while the pizza shop registered 1.105 ppm.

Taipei authorities said they ordered the restaurants to clean up their operations. The shops may also face fines, according to local news reports.

Shanghai's Gu said those levels, while they exceeded standards, would not cause acute poisoning. He also said it is rare to find inorganic arsenic in typical fast-food stores.

"High doses usually occur as organic arsenic in seafood," he said. "The Taiwan report may indicate tainted food."

The Taipei teams also found 12.4 to 22.4 parts per billion of acrylamide. As there are no standards for this substance, the county law bureau called on the island's government to develop protective regulations.

Acrylamide became a food safety issue after it was found accidentally by scientists in Sweden in 2002 in starchy foods, such as potato chips, French fries and bread that had been heated.

According to the US FDA, acrylamide is produced industrially for use in products such as plastics, grouts, water treatment products and cosmetics, and is also found in cigarette smoke.

High doses of acrylamide have produced cancer in lab animals, and people exposed to high levels at work have suffered nerve damage. But it is not clear whether acrylamide causes cancer in humans at the much lower levels found in food.

Health authorities in many countries and World Health Organization are doing research on the compound's effects on humans.

"China has no standards for acrylamide so far, but the government is doing research and developing regulations for it," Gu said. "We do regular checks for acrylamide to study local people's exposure to the chemical."

He said acrylamide is usually found in many fried foods but at very low levels.

KFC and McDonald's representatives contacted yesterday by Shanghai Daily said their foods meet state requirements.

(Shanghai Daily July 9, 2009)