China has suspended imports from several key US meat suppliers after months of international scrutiny over the safety of Chinese food and drugs.
China said some US chicken products had salmonella
Officials said they had found salmonella and growth-enhancers in several imported US chicken products.
Last year, 51 deaths in Panama were blamed on medicine tainted with Chinese chemicals and, this year, some US pets died from food with Chinese gluten.
China this week also executed a top official for approving unsafe drugs.
China's General Administration of Quality Supervision, Inspection and Quarantine said salmonella had been found in products from the largest US meat processor, Tyson Foods.
CHINESE PRODUCT SCARES
Pet food - tainted with chemical melamine
Toothpaste - tainted with chemical diethylene glycol and bacteria
Farmed fish - traces of banned drugs and pesticides found
Tyres - fault may cause blow-outs
Toys - contain lead or pose choking hazard
Children's jewellery - contains lead
Ceramic heaters - pose fire safety risk
Chicken feet supplied by Sanderson Farms had growth enhancers and anti-parasite drugs, it said.
Among the suspended US operators were Cargill Meat Solutions, AJC International and Triumph Foods.
Most of the firms have not yet commented, but a Cargill spokesman denied the claims.
Beijing has vowed to improve its quality control by streamlining its fractured monitoring system.
This week it also executed the former head of the State Food and Drug Administration, Zheng Xiaoyu, for taking bribes in approving unsafe drugs.
Quality control head Li Yuanping recently insisted tainted Chinese food exports were rare.
"All of them are exceptional cases. There is no such thing as zero risk. China-made products should not be labelled as substandard just because of a few bad producers."
Apart from pet food and cough syrup, international concern has also been raised over Chinese toothpaste, tyres, jewellery, seafood and toys.