The enzyme thrombin is derived from blood of pigs or cattle. It is used in food processing together with fibrinogen, a protein also obtained from the blood of these animals, to bind pieces of meat or fish.
Scientists of the Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF Panel) conclude that thrombin poses no safety concerns based on the fact that it derives from parts of the animals that are intended for human consumption and provided that it is produced under hygienic conditions in accordance with EU rules.
Thursday September 17, 2015/ EFSA/ European Union.
http://www.efsa.europa.eu