L-isoleucine from Corynebacterium glutamicum CCTCC M 2022764 authorised for all animals, also in water for drinking despite EFSA’s concerns — determined by ion-exchange chromatography with post-column derivatisation
Commission Implementing Regulation (EU) 2026/2087 of 18 September 2026, published on 21 September, authorises until 11 October 2036 L-isoleucine (≥ 90 % on a dry matter basis) produced by fermentation with a non-genetically modified strain. EFSA had concerns about its use in water for drinking (nutritional imbalance, hygiene); the Commission considered that feed business operators are to address the hygiene risks under the requirements of Regulation (EC) No 183/2005.
- Methods: identification of L-isoleucine in the additive — Food Chemicals Codex monograph; determination in the additive — ion-exchange chromatography with post-column derivatisation and optical detection (IEC-VIS/FLD or IEC-VIS), in premixtures — IEC-VIS/FLD or IEC-VIS under Regulation (EC) No 152/2009, in compound feed — IEC-VIS under 152/2009, in water for drinking — IEC-VIS.
- Five batches: L-isoleucine 95.5 % DM (95.4–95.6), L-leucine 1.11 % (specification ≤ 2 %), other amino acids 1.84 % (≤ 2 %), loss on drying 1.26 % (≤ 3 %), specific optical rotation 39.8° (39.4–40.3; specification +38.9° to +41.8°).
- In three batches aflatoxins were 0.84–1.47 µg/kg and the other mycotoxins were below the limits of quantification; lead, mercury and cadmium were also below the limits of quantification, arsenic up to 0.01 mg/kg. Salmonella and Enterobacteriaceae were not detected; the sum of dioxins and dioxin-like PCBs (upper bound) was 0.238 ng WHO-TEQ/kg.
- The label states the moisture content and a warning to take into account the dietary supply of all essential and conditionally essential amino acids when supplementing — especially via water for drinking. For ruminants L-isoleucine must be protected from ruminal degradation; EFSA could not conclude whether the additive irritates skin and eyes or sensitises the skin.