The strain of Propionibacterium acidipropionici under application is intended for use as a technological additive to improve the ensiling process at a proposed dose of 1.0 x 108 CFU/kg fresh material. The bacterial species P. acidipropionici is considered by EFSA to be suitable for the Qualified Presumption of Safety approach. As the identity of the strain has been clearly established and as no antibiotic resistance was detected, the use of the strain in the production of silage is presumed safe for livestock species, consumers of products from animals fed the treated silage and for the environment. Given the lack of information and its proteinaceous nature, the active agent should be considered to have a potential to be a skin and respiratory sensitiser. Three studies with laboratory-scale silos are described, each lasting at least 90 days, made using samples of grass forage of differing water-soluble carbohydrate content. In each case, replicate silos containing treated forage were compared to identical silos containing the same untreated forage at 20 ºC. No evidence of beneficial effects on fermentation characteristics or on the nutritional value of the final products was observed. However, the additive has the potential to improve aerobic stability of silage once exposed to air. This was demonstrated in moderately difficult and difficult to ensile forage species covering a range dry matter contents from 24 to 40 %.
