The United States on Friday hit imports of food enhancer MSG from China with high duties, saying the country is dumping the product in the US market at below cost.

The Department of Commerce's International Trade Administration (ITC) said it would collect a 52 percent anti-dumping duty on China-sourced monosodium glutamate.

MSG is used in many prepared foods to boost taste, and because it is widely found in Asian foods, it is often blamed for after-meal aches called Chinese Restaurant Syndrome.

The decision Friday hits trade that amounted to 26,600 tonnes of MSG bought from China last year, worth $33.5 million.

The action was a response to a petition by the US arm of Japanese food giant Ajinomoto, a leading global producer of MSG.

Two Chinese producer-exporters were singled out in the complaint: the Meihua Group and Shandong Linghua Monosodium Glutamate Inc.

The ITC also hit Indonesian MSG exporters, and specifically PT Cheil Jedang indonesia, with a 5.6 percent anti-dumping duty. Indonesia shipped 4,500 tonnes of MSG to the United States last year, worth $6 million.

The ITC decision is preliminary; a final ruling will be made in November.