According to local press, people became sick last week after eating pig organs bought from local markets in South China's Guangdong province. Symptoms included severe stomach pain and diarrhoea and several people were hospitalised, although the municipal health bureau claims that all patients have now been discharged.
An investigation revealed that the pig organs were contaminated with clenbuterol, a drug which prevents pigs from accumulating fat but is banned as a food additive because it can be fatal for humans.
The organs were distributed through markets in the Tianhe, Zengcheng and Baiyun districts of Guangzhou and were traced back to a number of farms in the Hunan province.
Authorities have arrested seven suspects in relation to the poisonings, all of whom are pork vendors from the associated districts. The bureau said two other suspects have been identified and would "be brought to justice soon."
The contamination is the latest in a string of food scares in China, the latest of which saw six children die and thousands fall sick after drinking milk contaminated with the industrial chemical melamine.
China's State Council recently announced plans to set up a new food safety commission to improve the country's food monitoring system.