CVM GFI #98 Dioxin In Anti-Caking Agents In Animal Feed And Feed Ingredients

Administrative guidance, not enacted legislation. This captured publisher edition preserves the listed document and attachments; later developments are not independently consolidated.

98
Guidance for Industry
Dioxin in Anti-Caking Agents Used in
Animal Feed and Feed Ingredients
This guidance supercedes guidance #98 of the same title, dated October 6, 1999
This guidance is intended to notify members of the feed industry of recent finding regarding the
presence of dioxin congeners that may be present in anti-caking agents and to offer general
advice regarding the monitoring of these products. This document has been revised in response
to comments to the October 6, 1999 version.
This guidance represents the agency's current thinking on the presence of dioxin congeners in
anti-caking agents. It does not create or confer any rights for or on any person and does not
operate to bind the Food and Drug Administration (FDA) or public. 	An alternative approach
may be used if such approach satisfies the requirements of the applicable statutes and
regulations.
Comments and suggestions regarding this guidance document should be submitted to the
Division of Dockets Management (HFV-305), Food and Drug Administration, 5630 Fishers
Lane, Room 1061, Rockville, MD 20852. 	All comments should be identified with the Docket
Number (99D-4201). 	Additional information on the original guidance document dated October
6, 1999 can be found in the Federal Register (Vol. 64, No. 199, October 15, 1999). Comments
may be submitted at any time.
For scientific questions regarding this guidance document, contact Randall Lovell, Center for
Veterinary 	Medicine 	(HFV-222), 	Food 	and 	Drug 	Administration, 	7519 	Standish 	Place,
Rockville, MD 20855, 240-453-6857 e-mail: randall.lovell@fda.hhs.gov.
U.S. Department of Health and Human Services
Food and Drug Administration
Center for Veterinary Medicine (CVM)
April 12, 2000

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Dioxin In Anti-Caking Agents Used in
Animal Feed and Feed Ingredients
Nearly two years ago, a multi-agency investigation tracked a previously unknown source of
dioxins in our food supply back to a clay anti-caking agent, called ball clay, used in animal feeds
and feed ingredients. Together, industry and government moved swiftly to eliminate the use of
ball clay in the animal feeds and thereby remove a source of dioxins in the human food chain.
In an October 7, 1997, letter to members of the feed industry, we stated that the origin and scope
of dioxins in clay deposits were unknown and, for this reason, mined clay products of all types
should be used with caution in the production of animal feeds. We advised companies offering
anti-caking products for animal feed uses to assure that their products were not contaminated
with dioxins.
Many industry participants tested clay products used in animal feeds in 1998. In particular, the
American Feed Industry Association (AFIA) led a "Dioxin Task Force" that assembled dioxin
data from a variety of sources and products. Based on our experiences with ball clay, one dioxin
congener, 2,3,7,8-tetrachlorodibenzodioxin (TCDD) was thought to be predominant.
Consequently, TCDD was all that was reported by the Dioxin Task Force to the CVM in
September 1998. Fifty-nine, non-ball clay, clay product samples were reported to all be below
the limit of detection for TCDD, with the detection limit in general being below 0.75 part per
trillion (ppt) measured as TCDD.
Also, in late 1998, FDA collected samples of clay and non-clay anti-caking products from feed
and oilseed sites where they were being used. The Environmental Protection Agency (EPA)
subjected the samples to the complete analysis for all 17 dioxin and furan congeners of
toxicological importance. The results of this survey prompted FDA to share our findings and
their implications for industry monitoring of clay and non-clay anti-caking products and our
future plans.
In brief, nine of fifteen samples of anti-caking, flow, and pelleting aid products were found to
contain detectable dioxins varying from less than 1 ppt toxicity equivalents (part per trillion
TEQ) to slightly over 20 ppt TEQ. Unexpectedly, the primary dioxin congener contributing to
the TEQ was 1,2,3,7,8-pentachlorodibenzodioxin (PeCDD). Very little, if any TCDD was found
in the samples. None of the samples appeared to be ball clay, but were identified as
montmorillonite," "bentonite," "ground clay," and even "silicate" and "lime."
FDA and EPA are continuing to investigate the sources of the more elevated samples; however,
the information thus far indicates the need for increased caution in industry surveillance for
dioxins in feed ingredients.
First, there is now evidence that dioxins can be present in clay and non-clay anti-caking products
other than ball clay. The current findings do not discount a natural origin for these residues.

Second, dioxin congeners other than TCDD, particularly PeCDD, may be present in important
amounts. Therefore, analyses for dioxins should be for the entire congener group that contributes
to the TEQ measurement, rather than just TCDD. Persons retaining samples of clay extracts that
were evaluated only for TCDD, for example, samples reported by the Dioxin Task Force, may
wish to consider re-submitting the samples for a more thorough analysis.
Third, the significance to public health of the relatively low concentrations of dioxins found in
the latest samples is presently unclear. On the one hand, these would seem to be small
contributions of dioxin to the human food chain. Most of the dioxin concentrations found in the
positive samples were on the order of one-one thousandth of the highest concentrations found in
ball clay. On the other hand, the limited samples may not be representative of the full range of
concentrations of dioxins that may be found in these products.
Because dioxins were not detected in six of fifteen samples, it appears that dioxins can be
minimized or avoided altogether in anti-caking agents. All clay and non-clay anti-caking
products for use in feeds or feed ingredients should be carefully monitored for dioxins, without
regard to how remote or pristine the source. We recommend that companies not use any clay or
non-clay anti-caking products contaminated with dioxin in animal feed and feed ingredients.
CVM plans to continue to sample regulated clay and non-clay anti-caking products for dioxins in
conjunction with EPA and other government agencies. Plans are also underway to sample other
feed components for dioxin. We will report back to you as new information becomes available.
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