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CPG Sec. 680.400 Medicated Feeds -- Combined Batches June 1986

Docket Number:
Issued by:
Guidance Issuing Office
Center for Veterinary Medicine
Office of Regulatory Affairs

Medicated feed CGMPs (Part 225) and type A medicated article CGMPs (Part 226) - combining discrete batches into a commingled lot


A number of manufacturers of type A medicated articles and medicated feeds produce discrete batches in batch mixers which are subsequently combined in a holding bin from which packaging occurs. The batches in the holding bin are often unit packaged to fill a single customer or packaging order. Although the product in the holding bin is not uniformly mixed as a unit, it is assigned a single lot number. The reason for this procedure is to permit efficient production practices and to facilitate unit packaging.


A single lot number may be assigned to commingled batches as described above provided the production and distribution records afford an identifiable history back to the individual batch records. If an individual batch or any portion of the commingled lot is out of potency specification or otherwise adulterated, the entire commingled lot will be considered adulterated.

Since the mixer batches are not subsequently mixed as a unit under this procedure, there is no assurance that samples from the holding bin are representative of the contents. Therefore, the sampling and assay schedules in the CGMPs are to be applied to the individual mixer batches, and not to the commingled lot.

As part of its internal quality control, the manufacturer should determine that ingredient segregation does not occur in the holding bins during the packaging process. This may be done by sampling and assaying periodically under an appropriately designed procedure, i.e., at appropriate intervals during packaging until the bin is empty.

Issued: 3/1/82
Revised: 6/1/86

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You can submit online or written comments on any guidance at any time (see 21 CFR 10.115(g)(5))

If unable to submit comments online, please mail written comments to:

Dockets Management
Food and Drug Administration
5630 Fishers Lane, Rm 1061
Rockville, MD 20852

All written comments should be identified with this document's docket number: FDA-2021-D-0644.


Contact Point
Center for Veterinary Medicine
Food and Drug Administration
7500 Standish Pl, HFV-1
Rockville, MD 20855
(240) 402-7002
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