Safety and efficacy of l-threonine produced by fermentation with Escherichia coli CGMCC 11473 for all animal species

nutritional additives, amino acids and their salts and analogues, L-threonine, safety, efficacy, genetically modified microorganisms
First published in the EFSA Journal
25. Juli 2017
5. Juli 2017
Scientific Opinion


The product subject of this assessment is l-threonine produced by fermentation with a genetically modified strain of Escherichia coli (CGMCC 11473). It is intended to be used in feed and water for drinking for all animal species and categories. It was not possible to characterise the genetic modification with the information provided. Uncertainty remained on the possible presence of cells from the production strain and their recombinant DNA in the product. Therefore, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) could not conclude on the safety of the product l-threonine, produced by fermentation with Escherichia coli CGMCC 11473 for the target species, consumers and the environment. The FEEDAP Panel has concerns on the safety of the simultaneous oral administration of threonine containing additives via water for drinking and feed. In the absence of data, the FEEDAP Panel cannot conclude on the potential of the additive to be an irritant for skin and eyes or to be a skin sensitiser. There is a risk from the exposure by inhalation to endotoxins for persons handling the additive. The product under assessment is considered an efficacious source of the amino acid l-threonine for all animal species. For l-threonine to be as efficacious in ruminants as in non-ruminant species, it requires protection against degradation in the rumen.

Panel members at the time of adoption

Gabriele Aquilina, Giovanna Azimonti, Vasileios Bampidis, Maria de Lourdes Bastos, Georges Bories, Andrew Chesson, Pier Sandro Cocconcelli, Gerhard Flachowsky, Jürgen Gropp, Boris Kolar, Maryline Kouba, Marta López-Alonso, Secundino López Puente, Alberto Mantovani, Baltasar Mayo, Fernando Ramos, Guido Rychen, Maria Saarela, Roberto Edoardo Villa, Robert John Wallace and Pieter Wester.
Panel on Additives and Products or Substances used in Animal Feed
feedap [at]
EFSA Journal 2017;15(7):4939
Question Number
On request from
European Commission