393 Pure Appl. Chem., Vol. 82, No. 2, pp. 393–407, 2010. doi:10.1351/PAC-CON-09-07-06 © 2010 IUPAC, Publication date (Web): 25 January 2010 Organic forms of trace elements as feed additives: Assessment of risks and benefits for farm animals and consumers* Alberto Mantovani ‡ , Chiara Frazzoli, and Francesco Cubadda Food and Veterinary Toxicology Unit, Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy Abstract: Essential trace elements (TEs) are major nutritional feed additives, required for the health and welfare of farm animals, especially under intensive husbandry conditions. Within the European Food Safety Authority (EFSA), risk assessment of feed additives is carried out by the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP), which is increasingly confronted with additives based on organic forms of TEs. Organic forms are expected to have higher bioavailability, hence, lower levels in feeds may be needed to meet farm animal requirements. On the other hand, higher bioavailability might also lead to enhanced deposition in edible tissues, hence, increased consumer exposure; specific or- ganic forms might also have a different distribution in edible tissues or products. Higher con- sumer exposure is especially relevant to TEs with recognized health risks at excess levels (e.g., Se); exposure scenarios should take into account background dietary levels and other intake sources (e.g., supplements). Tolerable upper intake levels (ULs) for adults and chil- dren are the basis for risk assessment; when no UL is defined (e.g., for Mn), a conservative estimate should assess whether the organic form in feeds might significantly increase the consumer’s intake above the dietary background. In perspective, specific maximum allow- able contents might be considered for organic forms of TEs in feeds, when supported by a robust database as well as by targeted analytical methods. Keywords: bioavailability; chromium; exposure; farm animals; food safety; manganese toxi- cology; selenium. INTRODUCTION Feed additives are a large and heterogeneous group of substances, from enzymes through to nutrients, used to improve the quality of feeds for farm animals: they make up the bulk of chemicals used in farm animal production and may significantly influence the wholesomeness of foods of animal origin [1]. Since 2003, the risk assessment of feed additives in Europe has been carried out by the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) within the European Food Safety Authority (EFSA) [2]. The assessment of feed additives is a complex, multidisciplinary task [1]. The substance should be credible from the efficacy standpoint; tolerance studies in target species should assess the margin of safety between the intended concentrations in feed and the level where initial un- *Paper based on a presentation at the 3 rd International Symposium on Trace Elements in Food (TEF-3), 1–3 April 2009, Rome, Italy. Other presentations are published in this issue, pp. 349–481. ‡ Corresponding author: Tel.: +39 (0)6 4990 2815/2658; Fax: +39 (0)6 4990 2658; E-mail: alberto.mantovani@iss.it; Web site: http://www.iss.it/inte/