Consumers in Tianjin reported that some shrimps were recently found injected with gelatin, China National Radio reported Wednesday.

A local resident surnamed Zhang said that a couple of days ago she bought 2.5 kilograms of shrimps that looked big and fresh at a market in Heping district. But when she washed them at home, they were easily broken and had some jelly-like material inside.

A shrimp allegedly injected with gelatin in Tianjin on Feb 7, 2011. [Photo/CFP]

Vendors said the jelly-like material is gelatin, which makes shrimps look fresher and weigh more. Injected shrimps weigh 20 to 30 percent more.

They also said the material was a legal food additive and posed no harm to human health.

No authority has yet confirmed whether gelatin is harmless to humans. But this kind of business practice has been targeted in Tianjin. In September 2011, a company that injected shrimps with gelatin was shut down and 170 kilograms of shrimp were seized.