Enterococcus faecium ATCC 53519 and ATCC 55593 as silage additives (1k20603, 1k20604): counts on bile esculin azide or Slanetz-Bartley agar (EN 15788) — efficacy accepted after four EFSA opinions, once dry matter loss was recalculated with the Weissbach correction for volatiles
Commission Implementing Regulation (EU) 2025/1465, published on 23 July 2025, authorises until 12 August 2035 two preparations of Enterococcus faecium (ATCC 53519 and ATCC 55593, in the register as SF202-DSM 4788 and SF301-DSM 4789) as silage additives for all animal species. In 2013 EFSA found them safe but without proof of efficacy; in its opinions of 27 September 2022 and 4 July 2023 it still could not confirm it — only the opinion of 15 October 2024 (applicant FEFANA asbl), based on the same data with a different dry matter correction, reached a positive conclusion.
- Methods in the annex: identification — PFGE (CEN/TS 17697) or DNA sequencing; count in the additive — spread or pour plate on bile esculin azide agar or Slanetz and Bartley agar according to EN 15788. Both preparations: min. 1 × 10¹⁰ CFU/g, solid form. Minimum dose when not combined with other silage microorganisms: 1 × 10⁷ CFU/kg fresh material (ATCC 53519) and 5 × 10⁶ CFU/kg (ATCC 55593); all types of fresh plant material.
- Why it took so long (2024 opinion): three in vitro experiments — maize (easy to ensile), alfalfa (moderately difficult) and high-moisture maize (difficult), four replicates each, 90 days. In 2022 the only effect was a lower dry matter loss, but without correction for volatile fermentation products. In 2023 the correction (Porter and Murray, 2001) was also subtracted from the dry matter of the fresh material before fermentation, and the formula did not suit the type of silage. In 2024 the same data set was recalculated with the Weissbach (2009) method, described for silages used as biogas substrate.
- Results after the Weissbach correction (control / ATCC 53519 / ATCC 55593): dry matter loss in maize 6.32 / 0.19 / 1.00 %, in alfalfa 2.04 / 0.20 / 0.25 %, in high-moisture maize 7.16 / 6.47 / 6.48 % — all differences significant. pH unchanged (3.70–3.73 in maize, 4.33–4.40 in alfalfa, 4.45–4.50 in high-moisture maize); in maize lactic acid fell from 4.47 to 3.82 and 3.96 % DM and acetic acid from 1.08 to 0.87 %. Ammonia nitrogen without significant differences.
- Safety (2013 opinion, cited in the act): safe for all species, consumers and the environment; in the absence of data the additives are considered skin and eye irritants, potential skin sensitisers and — because of their proteinaceous nature — respiratory sensitisers; most of the preparations tested were very dusty. Hence skin, eye and respiratory protection. Transitional period: additives and feed labelled before 12 August 2026 under the previous rules — until stocks are exhausted.