A husband and wife in Chengdu, Sichuan province, were each sentenced to one year imprisonment and fined 20,000 yuan ($3,260) between them on Monday for producing and selling poisonous blood tofu, a Chinese delicacy, Chengdu Commercial Daily reported on Tuesday.

The husband surnamed Wang and the wife surnamed Shen, both 44 and residents of the city, bought pig blood to make blood tofu from May 2008 to August 2013.

The couple added formaldehyde during the process to make the dish last longer, and sold the poisonous and harmful blood tofu at local markets.

They were seized by commercial and industrial authority on Aug 1, 2013, with 60 kg of the tainted blood tofu they had made that day.