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My feed label says it contains "zeolite." What is this, and is it allowed in feed for organic livestock?

By Deder Siedler

Zeolite is a generic term for a class of porous minerals that exhibit unique qualities as adsorbents, carriers and catalysts. The zeolite in your livestock feed is likely a “flow agent” or anti-caking treatment, which adsorbs moisture to keep the feed dry. The FDA considers zeolites to be GRAS (Generally Regarded As Safe), but does put restrictions on their use. Zeolite is composed of porous crystals of silicon and aluminum, and the material can be loaded with other ions such as sodium, potassium, calcium, and magnesium. The most common forms that farmers might see are sodium silico-aluminate (SSA), calcuim aluminosilicate (CAS) and hydrated sodium calcium alumino-silicate (HSCAS).

With all this potential mineral content, you can imagine zeolite might also be used as a vehicle for feed minerals. While the National Organic Program (NOP) standards allow feed supplements and additives to contain naturally mined minerals (205.237(a)) and some synthetics (205.603(d)(2) “–when FDA approved”), the FDA places special restriction on the use of zeolite in feed (see 21 CFR 582.2122, .2727, and .2729) as a flow agent only. The FDA regulations limit the use of the three common zeolite forms to only 2% of the total feed ration, and restrict the allowance for the purposes of anti-caking only. By placing the allowance for these zeolite forms in the specific anti-caking agent section (subpart C) versus another section (e.g., part F: Nutrients and Supplements), the regulations seem to indicate that the use of zeolite as a mineral supplement in feed is not allowed. For an organic producer, this is important since the NOP standards state: 205.237(b)(6): The producer of an organic operation must not…Use feed, feed additives, and feed supplements in violation of the Federal Food, Drug, and Cosmetic Act (i.e., the FDA regulations).

Zeolite does form naturally, and millions of tons are mined every year, but the reality is that most of what is sold and produced consists of synthetic forms of the substance. None of the synthetic forms are allowed on the National List for feed supplements or additives. Be assured that any zeolite in an OMRI Listed® product has the manufacturing process carefully reviewed to verify that it is a natural, mined form.

Revised and updated in October 2015 by OMRI Technical Director Johanna Mirenda. This article was originally published in the Fall 2012 edition of the OMRI Materials Review newsletter.