Oyster fans might want to reduce their consumption of the mollusks as test results in Guangzhou showed they contained excessive amounts of cadmium and other heavy metals.

Following a scandal of cadmium-tainted rice in the southern province, China Central Television reported that 1 kilogram of oysters sold at a Guangzhou restaurant, famous for grilled oysters, contained 2 mg of cadmium, 20 times the permitted content stipulated in a national standard drafted by the health authority.

More than 5,000 kilograms of oysters are consumed in Guangzhou a day, Guangzhou-based Yangcheng Evening News reported.

Oysters and beer are brand dishes for many restaurants in the southern metropolis where all types of seafood are part of the diet.

Liu Yimin, deputy president of Guangzhou No 12 Hospital, warned that eating too many contaminated oysters will harm people’s health.