Most Chinese are unsatisfied with food safety in the country, according to a survey released on Thursday amid a scandal that dragged in many fast food giants.

Eighty percent of the 3,166 respondents said they are not satisfied with food safety in China, according to the survey conducted by the Beijing research company Horizon Research and Horizonkey, which polled people aged 18 to 60 in 20 cities.

Respondents said food companies are the chief culprits of poor food safety. About 60 percent said food companies have performed poorly in food safety, more so than the other groups - food industry associations (50 percent), government (29 percent) and media (26 percent).

Wang Zhutian, assistant director of the China National Center for Food Safety Risk Assessment, said the survey results suggest the government should make more efforts to hold food companies accountable for the products they provide to customers.

He urged harsher punishment for companies that produce or process tainted food and more pressure on their business partners to stop cooperating with them in order to make sure that irresponsible food companies cannot survive in the market.

Authorities are expanding their checks on food after a Shanghai company allegedly used expired meat and supplied it to big names including McDonald's and KFC.

In Zhejiang province, authorities have expanded their inspection to raw food supplies and more than 1,800 companies have been checked.

In the Inner Mongolia autonomous region, more than 700 kilograms of products supplied by Shanghai Husi Food, suspected of using expired meat, have been sealed.

McDonald's said on Thursday it has ended its contract with Shanghai Husi Food, a subsidiary of US-based OSI Group. Yum! Brands, which owns KFC and Pizza Hut, said its China outlets would not buy from any OSI China factory. But McDonald's said it will buy from OSI's factories in Henan and Hebei provinces.

Sheldon Lavin, chairman, chief executive officer and owner of OSI Group, said using expired meat "is completely unacceptable" and "terribly wrong". "We will bear the responsibility of these missteps, and will make sure that they never happen again," he said.