Metal Proteinates

How do the National Organic Program (NOP) regulations apply to the manufacture or use of metal proteinates in livestock feed?

By Amber Lippert

A metal proteinate is a mixture of a mineral (such as zinc sulfate) with a protein carrier (such as hydrolyzed soy protein meal). During mixing the metal compound (mineral) and ligand (protein source) bond together and create a chelate complex with more than one binding site. The chelated trace mineral is stable and protected during digestion from chemical reactions that would render the mineral unavailable to the animal. OMRI does not consider chelation itself a synthetic process; nonsynthetic chelaters are common (humates are an example). Nor is the metal (e.g., elemental zinc) itself synthetic. It is the soluble trace mineral, metal salt (e.g., zinc sulfate) that is synthetic due to synthetic reactions occurring during manufacture.

Per the NOP regulations at §205.603(d)(2), synthetic trace minerals are allowed as feed supplements when FDA approved. NOP Guidance 5030 further clarifies that minerals that are listed in the current edition of the Association of American Feed Control Officials (AAFCO) official publication are approved, as long as the producer does not use feed supplements or additives in amounts above those needed for adequate nutrition and health maintenance for the species at its specific stage of life (i.e., should not be used to stimulate growth). Metal proteinates, including those made with calcium, cobalt, copper, iron, magnesium, manganese, and zinc are listed in the AAFCO manual under trace minerals, and are recognized by the FDA. Proteinates made with these metals comply with the NOP regulations, and are the common proteinates used in livestock feed additive products.

Another requirement for metal proteinates used in organic livestock feed is that they must not contain protein produced using excluded methods (GMOs) or sourced from slaughter byproducts per §205.105(g) and §205.237 respectively, of the NOP regulations. Producers should always check with their certifying agent prior to using any new substance.

Revised and updated in December 2016 by OMRI Technical Director Johanna Mirenda. This article was originally published in the Winter 2013 edition of the OMRI Materials Review newsletter.