#258
 
 
Use of Tracers in Animal Food, Type 
A Medicated Articles, and Medicated 
Feeds  
 
Guidance for Industry  
 
This guidance replaces Compliance Policy Guide Sec. 680.100 Tracers in Animal Feed. 
 
Submit comments on this guidance at any time.  Submit electronic comments to 
http://www.regulations.gov.  Submit written comments to the Dockets Management Staff (HFA-
305), Food and Drug Administration, 5630 Fishers Lane, Rm.  1061, Rockville, MD 20852.  All 
written comments should be identified with the Docket No. FDA-2021-D-1246. 
 
For further information regarding this document, contact AskCVM@fda.hhs.gov. 
  
Additional copies of this guidance document may be requested from the Policy and Regulations 
Staff (HFV-6), Center for Veterinary Medicine, Food and Drug Administration, 7500 Standish 
Place, Rockville, MD 20855, and may be viewed on the Internet at https://www.fda.gov/animal-
veterinary, https://www.fda.gov/regulatory-information/search-fda-guidance-documents, or 
http://www.regulations.gov. 
 
 
 
 
 
U.S. Department of Health and Human Services 
Food and Drug Administration 
Center for Veterinary Medicine 
October 2022
 
  Contains Nonbinding Recommendations 
 
Use of Tracers in Animal Food, Type A Medicated Articles,          
and Medicated Feeds 
 
Draft Guidance for Industry 
 
This guidance represents the current thinking of the Food and Drug Administration (FDA or 
Agency) on this topic.  It does not establish any rights for any person and is not binding on FDA 
or the public.  You can use an alternative approach if it satisfies the requirements of the 
applicable statutes and regulations.  To discuss an alternative approach, contact the FDA staff 
responsible for this guidance as listed on the title page. 
 
I.  Introduction 
 
FDAs Center for Veterinary Medicine (CVM) receives inquiries regarding the use of tracers 
in animal food, Type A medicated articles, and medicated feeds.  Tracers are ingredients added 
to these products to identify a particular product.  The purpose of this document is to provide 
guidance on the use of tracers in animal food, Type A medicated articles, and medicated feeds.  
This guidance replaces Compliance Policy Guide (CPG) Sec. 680.100 Tracers in Animal Feed. 
 
In general, FDAs guidance documents do not establish legally enforceable responsibilities. 
Instead, guidances describe the Agencys current thinking on a topic and should be viewed only 
as recommendations, unless specific regulatory or statutory requirements are cited.  The use of 
the word should in Agency guidance means that something is suggested or recommended, but 
not required. 
 
II.  Background 
 
Manufacturers of animal food, Type A medicated articles, and medicated feeds use tracers 
to identify a particular product, to allow for determination of the presence of a particular 
ingredient, or for other purposes.  Tracers are designed to be inert, harmless, and easily 
detectable.   
 
A tracer may be added to an ingredient, such as a mineral premix or a Type A medicated 
article, that will be used to manufacture a finished animal food.  The finished animal food 
can be tested for the presence of the tracer and hence, the presence of the ingredient.  For 
example, the manufacturer of a Type A medicated article may add a tracer to allow 
confirmation of the presence of that manufacturers Type A medicated article in a Type B or 
Type C medicated feed, helping to discourage counterfeiting.  The manufacturer of a 
mineral premix may add a tracer to allow another animal food manufacturer using that 
premix to ensure the correct ingredient was used in the food and is present at the appropriate 
inclusion rate.  Animal food manufacturers may also use tracers to ensure that their 
manufacturing processes are adequate and under control.  In these cases, a tracer would be 
used intermittently to assess the adequacy of the manufacturing process and would not be 
present in all products.   
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  Contains Nonbinding Recommendations 
 
Some types of tracers may require specific analyses to be detected, while other types of 
tracers may be detected by visual inspection.  For example, a tracer could be reduced iron 
particles combined with an approved color additive.   
 
III.  Policy  Animal Food 
 
Substances intended for use as tracers in animal food are animal food products.  If a tracer 
with the appropriate characteristics is used, measuring the amount of that tracer in an animal 
food can help a manufacturer make sure that an ingredient is present and uniformly mixed 
into that animal food. 
 
Any substance/ingredient intentionally added to an animal food must be used in accordance 
with a food additive regulation (see 21 CFR part 573), unless it is generally recognized as 
safe (GRAS) among qualified experts for its intended use as described in 21 CFR 570.30, or 
it qualifies for an exemption from the definition of  food additive in section 201(s) of the 
Federal Food, Drug, and Cosmetic Act (FD&C Act)1 (see section 409(a)(2) of the FD&C 
Act). 
 
The Association of American Feed Control Officials (AAFCO) defines certain ingredients 
that are used as tracers in its Official Publication.2  FDA does not intend to prioritize 
enforcement of applicable food additive requirements regarding the use of these ingredients 
published in the AAFCO Official Publication, provided there are no safety concerns about 
their use as tracers or their composition. 
 
If you seek to use a tracer in animal food that is not included in AAFCOs Official 
Publication, it must be used in accordance with a food additive regulation, unless it is GRAS 
or otherwise exempt from the food additive definition (see section 409(a)(2) of the FD&C 
Act).  FDA issues food additive regulations specifying the conditions under which an 
additive has been demonstrated to be safe and, therefore, may be lawfully used (see section 
409(a)(2) of the FD&C Act and 21 CFR part 573).  Section 409(b) through (g) of the FD&C 
Act provides for a petition process to establish that a use of a food additive is safe (see 21 
CFR part 573).3   
 
Like other animal food products, tracer products must comply with all applicable animal 
food label and labeling requirements.  All ingredients in a tracer product, as required in 21 
 
1 Under section 201(s) of the FD&C Act, the following types of substances are excluded from the food additive 
definition: (1) pesticide chemical residues in or on a raw agricultural commodity or processed food; (2) pesticide 
chemicals; (3) color additives; (4) substances used in accordance with a prior sanction (i.e., a sanction or approval 
granted prior to the enactment of the Food Additives Amendment of 1958 under the FD&C Act, the Poultry 
Products Inspection Act, or the Meat Inspection Act); (5) new animal drugs; and (6) dietary ingredients in or 
intended for use in a dietary supplement (not applicable to animal food).  
2 The AAFCO Official Publication may be obtained at https://www.aafco.org/Publications. 
3 See CVM Guidance for Industry #221, Recommendations for Preparation and Submission of Animal Food 
Additive Petitions (June 2015) (https://www.fda.gov/media/86905/download). 
 
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  Contains Nonbinding Recommendations 
 
CFR 501.4(a) except as permitted elsewhere, must be included in the ingredients list using 
their appropriate common or usual name and must be listed in descending order of 
predominance by weight.   
       
When a color additive is used as a component of a tracer in animal food, the color additive 
must be listed in 21 CFR part 73, subpart AFoods, or in 21 CFR part 74, subpart AFoods, 
and be approved for the coloring of foods generally (see sections 721(a) and 402(a)(2)(A) of 
the FD&C Act).  How color additives may be identified in the ingredients list of an animal 
food is specified in 21 CFR 501.22(k)(1) and (2). 
 
Under 21 CFR 501.100(a)(3), incidental additives that are present in a food at insignificant 
levels and that do not have any technical or functional effect in that food are exempt from 
the requirement of a declaration on the label of their common or usual name.  If the use of a 
tracer in animal food qualifies for the labeling exemption at 21 CFR 501.100(a)(3) for 
incidental additives, the tracer is exempt from the requirement that its presence be declared 
on the label of the finished food.  In addition, there are uses of tracers where disclosing the 
presence of the tracer on product labeling would defeat its intended purpose, such as when a 
tracer is used for the detection of a counterfeit, or be impractical, such as when a tracer is 
used only intermittently to assess manufacturing controls.  In these instances, FDA does not 
intend to prioritize enforcement of the applicable animal food labeling requirements (21 
CFR 501.4) for tracer ingredients used in animal food products if these ingredients are 
defined as tracers in the AAFCO Official Publication.   
 
IV.  Policy  Type A Medicated Articles  Medicated Feed 
 
Section 512 of the FD&C Act requires that the use of all ingredients in a new animal drug 
be approved via a new animal drug application or supplement.  Therefore, a tracer may be 
used as an inactive ingredient in a Type A medicated article only if its use is approved via a 
new animal drug application (NADA), an abbreviated new animal drug application 
(ANADA), a conditionally approved new animal drug application (CNADA), a supplement 
to any of these applications, or permitted via a listing on the Index of Legally Marketed 
Unapproved New Animal Drugs for Minor Species (Index listing).   
 
As part of the pre-approval review of the (A)/(C)NADA, supplement, or Index listing for a 
Type A medicated article, FDA considers whether a proposed tracer can be used in the 
medicated article and whether it must be declared on the labels of the Type A medicated 
article and medicated feed manufactured from it.  FDA will generally find that a tracer 
which has previously been accepted for use in animal foods can be used in a Type A 
medicated article.  If FDA has previously not prioritized enforcement of the applicable 
animal food labeling requirements (21 CFR 501.4) for a tracer ingredient used in animal 
food products or has previously not prioritized enforcement of the applicable new animal 
drug labeling requirements for another Type A medicated article label (21 CFR 201.10), 
then FDA would generally not prioritize enforcement of the applicable new animal drug 
labeling requirements for a tracer ingredient used in a Type A medicated article. 
 
Changes in the qualitative or quantitative formulation of an approved new animal drug, 
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  Contains Nonbinding Recommendations 
 
including changes in the inactive ingredients, are considered major changes and must be 
submitted in a Prior Approval Supplement unless a regulation or guidance provides for a 
less burdensome notification of the change (see 21 CFR 514.8(b)(1)(iii)).4  A holder of an 
approved application or Index listing for a Type A medicated article who wants to add a 
tracer must submit a Prior Approval Supplement (see 21 CFR 514.8(b)(2)(ii)(A)).  If the 
tracer has previously been found acceptable for use in animal food, the holder may instead 
submit a Supplement  Changes Being Effected in 30 Days (see 21 CFR 514.8(b)(3)). 
 
The following information should be provided in an (A)/(C)NADA, a supplement to an 
approved (A)/(C)NADA, or Index listing to support the addition of a tracer to a Type A 
medicated article: 
  A full description of the tracer, including all of its components, using the appropriate 
common or usual name(s) or scientific data and information that identify each 
component; 
  Specifications and test methods for the tracer; 
  A batch formula, manufacturing instructions, and specifications for the Type A 
medicated article containing the tracer; 
  Data to demonstrate that the tracer does not interfere with the assay of the drug in 
the Type A medicated article and the medicated feed; 
  Stability data to support the requested expiry period of the Type A medicated article 
containing the tracer; and   
  For a tracer that has not previously been accepted by FDA for use in animal food, 
any additional data that may be needed to demonstrate the tracer is safe for its 
intended use.  
   
Measurement of the amount of tracer in a medicated feed manufactured from a Type A 
medicated article containing the tracer is not an acceptable substitute for the periodic drug 
assays required in 21 CFR 225.58, or any other drug assays, such as those used for 
medicated feed stability studies required in 21 CFR 514.1(b)(5)(x).    
 
4 See CVM Guidance for Industry #83, Chemistry, Manufacturing and Controls Changes to Approved 
NADA/ANADA (May 2007) (https://www.fda.gov/media/70323/download). 
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