Efficacy of Saccharomyces cerevisiae (NBRC 0203), Lactobacillus plantarum (NBRC 3070) and Lactobacillus casei (NBRC 3425) as a silage additive for all species
The product under assessment is a preparation containing single strains of Saccharomyces cerevisiae, Lactobacillus plantarum and Lactobacillus casei to be used as a technological additive to improve the ensiling process. EFSA has been previously requested by the European Commission to evaluate this product. The safety of the additive for consumers, users, the environment and target animals was established at that time. Results from a number of in vitro ensiling studies made using a variety of grass forage and maize samples were also presented. These efficacy studies showed no evidence that the additive had the potential to conserve nutrients and so improve the production of silage. There was, however, evidence for improved aerobic stability once the ensiled material was exposed to air, but because of the apparent variability in the additive mix, an effective dose could not be established. The applicant has now provided a number of additional ensiling studies confirming that the additive when applied at 80 mL/tonne significantly increases the aerobic stability of ensiled material after exposure to air. This was shown in forage materials with dry matter contents varying between 30% and 70%. Fluorescence in situ hybridisation methods were also introduced to better characterise the additive. Although this method allows individual strains to be separately enumerated, bacterial and yeast numbers are expressed as cell numbers/mL and include counts of both viable and non-viable cells. As a result values cannot be equated to colony-forming units, the basis of any authorisation and the functional properties of the additive. Consequently, the Panel remains unable to identify a minimum specification for the product or a minimum effective dose.