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 Dockets Management Branch (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 general questions regarding this guidance document,
contact Judy Gushee, Center for Veterinary Medicine (HFV-232), Food and
Drug Administration, 7500 Standish Place, Rockville, MD 20855,
301-827-0150, e-mail: jgushee@cvm.fda.gov.
For scientific questions regarding this guidance document, contact
Randall Lovell, Center for Veterinary Medicine (HFV-222), Food and Drug
Administration, 7500 Standish Place, Rockville, MD 20855, 301-827-0176,
e-mail: rlovell@cvm.fda.gov.
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.
This guidance supercedes guidance #98 of
the same title, dated October 6, 1999
SOURCE: U.S. Department of Health and Human
Services Food and Drug Administration Center for Veterinary Medicine (CVM)
April 12, 2000 |