Pediococcus pentosaceus is a technological additive intended to improve the ensiling process at a minimum proposed dose of 1 × 108 colony-forming units (CFU)/kg fresh material. The P. pentosaceus strain was found to be resistant to tetracycline by an unidentified mechanism and thus may pose a risk for the spread of genes coding for resistance to an antibiotic of human and veterinary importance. Thus, the additive containing this strain is not considered safe for the target animals and consumers of products from animals fed the treated silage. The additive should be regarded as a skin and eye irritant and a potential skin and respiratory sensitiser, and treated accordingly. Since the P. pentosaceus strain carries an uncharacterised resistance to tetracycline, the FEEDAP Panel cannot conclude on its safety for the environment. A total of seven studies with laboratory-scale silos were made using samples of forage of differing water-soluble carbohydrate content. In each case, replicate silos containing treated forage were compared with identical silos containing the same but untreated forage. The results showed that the additive has the potential to improve the production of silage from easy, moderately difficult and difficult to ensile forage species by reducing the pH and increasing the preservation of dry matter. This was most consistently shown at application rates of 5 × 107 and 1 × 108 CFU/kg forage.
