Opinion of the Scientific Panel on Additives and Products or Substances used in Animal Feed on a request from the Commission on the safety of BioProtein: product of fermentation from natural gas

“Bioprotein” is a biomass preparation from bacterial origin, has been authorised for animal feeding. Later, concerns were expressed for the safety because of effects on the (mainly nonspecific) immune system in laboratory animals, notably when BioProtein (BP) was modified to be used for human consumption. European Food Safety Authority (EFSA) was asked to express an opinion on newly submitted studies after the opinion of SCAN (Scientific Committee on Animal Nutrition) in 2003, with focus on the effects on the immune system. The submitted data included a single generation reproduction study and an antibody study in parent and young rats fed BP, with or without immunisation with BP. In these studies the effects on haematology, lymphoid organs and antibody production were studied in parents and offspring fed Bioprotein at different periods during the development. These studies indicate that in animals fed Bioprotein under specific circumstances (feeding at very early age, or after immunization) the effects were diminished or partially reversible. This may indicate that the effects are, at least partially, subject to adaptation; however, they do not alleviate the concerns for animal and human safety, as previously expressed by SCAN, for BioProtein.