Two people went on trial on April 17, charged with producing and selling poisonous food in Central China's Henan province.

The case is the first involving the sale of poisonous beef blood that a court in the province has handled, the Zhengzhou Evening News reported on April 18.

Prosecutors in Luoyang said that beef blood sold by the accused, a brother and sister, had 184 micrograms of formaldehyde per kg, hundreds of times higher than allowed.

Formaldehyde can delay the decay of beef blood and improve its texture and taste, but it is not a legal food additive because it can damage health and even cause cancer.

No death or injuries linking the consumption of the beef blood had been reported.

The siblings, whose real names were not revealed, said they ate the blood themselves as they did not know formaldehyde was poisonous, and added that the blood sold well in local restaurants.

The two were detained in September after police found 150 kg of beef blood that tests later determined to have an excessive amount of formaldehyde, according to the report.

The amount of beef blood the pair sold is still unknown due to the absence of sales record and accounting books. The brother had said they sold about 60 tons of such beef blood in half a year, but later said about 10 tons were sold.