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M-I-05-5: Tolerance and/or Safe Levels of Animal Drug Residues in Milk (Replaces M-I-03-9 (June 30, 2003) and identifies it as "INACTIVE") and also identifies M-I-92-1 as "INACTIVE"

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September 27, 2005 

TO: All Regional Food and Drug Directors
Attn: Regional Milk Specialists

FROM: Milk Safety Branch (HFS-626)

SUBJECT: Tolerance and/or Safe Levels of Animal Drug Residues in Milk (Replaces M-I-03-9 (June 30, 2003) and identifies it as "INACTIVE") and also identifies M-I-92-1 as "INACTIVE"

The 1991 National Conference on Interstate Milk Shipments made changes to the Grade "A" Pasteurized Milk Ordinance (PMO) establishing Appendix N. This Appendix references the publication of tolerances and/or safe levels of animal drug residues in milk. This M-I provides the updated referenced list. This M-I is replacing M-I-03-9 and will be reissued when additional toxicological data becomes available.

Tolerances 1
Antimicrobials
Drugppb2Drugppb2
Amoxicillin10Neomycin150
Ampicillin10Novobiocin100
Bacitracin500Penicillin 50
Cephapirin20Pirlimycin400
Ceftiofur3100Sulfadimethoxine10
Cloxacillin10Tetracyclines 6300
Dihyrdrostreptomcyin125Tylosin50
Erythromycin40  

1 Tolerances for new animal drugs in milk are found in 21 CFR 556
2 Note that 1 ppb = .001 ppm or 1 ppm = 1000 ppb
3 The tolerance was established for the marker residue, not the parent compound
4 A safe level of 50 ppb has been established for erythromycin
5 A safe level of 5 ppb has been established for penicillin
6 This tolerance includes both the sum and the individual residues of chlortetracycline, oxytetracycline and tetracycline.


Other Drugs
Drugppb1Drugppb1
Clopidol20Methylprednisolone10
Eprinomectin212Moxidectin40
Fenbendazole2600Thiabendazole50
Flunixin22Tripelennamine20
Hydrocortisone10  

1 Note that 1 ppb = .001 ppm or 1 ppm = 1000 ppb
2 The tolerance was established for the marker residue, not the parent compound

Appendix N of the PMO states: "Safe levels" are used by FDA as guides for prosecutorial discretion. They do not legalize residues found in milk that are below the safe level. In short, FDA uses the "safe levels" as prosecutional guidelines and in full consistency with CNI v. Young stating, in direct and unequivocal language, that the "safe levels" are not binding. They do not dictate any result; they do not limit the Agency's discretion in any way; and that they do not protect milk producers, or milk from court enforcement action.

"Safe levels" are not and cannot be transformed into tolerances that are established for animal drugs under Section 512 (b) of the FFD&CA as amended. "Safe levels" do not:

  1. Bind the courts, the public, including milk producers, or the Agency, including individual FDA employees; and
  2. Do not have the "force of law " of tolerances, or of binding rules."

Under CNI v. Young, FDA is not precluded from taking action against a product with a residue level below the safe level, nor is FDA unable to exercise enforcement discretion when the safe levels are exceeded. FDA will make this determination depending on circumstances and available evidence on a case-by-case basis.

Safe Levels in Milk
Drugppb1Drugppb1
Erythromycin50Sulfamethazine10
Gentamicin30Sulfamethizole10
Penicillin5Sulfanilamide10
Sulfachloropyridazine10Sulfapyridine10
Sulfadiazine10Sulfaquinoxaline10
Sulfamerazine10Sulfathiazole10

1 Note that 1 ppb = .001 ppm or 1 ppm = 1000 ppb

Extra-label use of sulfonamide drugs in lactating dairy cattle (except approved use of sulfadimethoxine, sulfabromomethazine and sulfaethoxypyridazine) is prohibited by 21 CFR 530.41.

This coded memorandum provides an updated reference list and subsequently the tolerances and/or safe levels of animal drug residues in milk contained in M-I-91-4 (July 21, 1991) and M-I-92-1 (March 6, 1992) are not valid. Additional information from these coded memoranda has been incorporated into other NCIMS documents. Because of this we are identifying M-I-92-1 as "INACTIVE".

NOTE: We have previously identified M-I-91-4 as "INACTIVE" in the Index of Memoranda of Information (M-I).

An electronic version of this memorandum is available for distribution to Regional Milk Specialists, State Milk Regulatory Agencies, State Laboratory Evaluation Officers, and State Milk Sanitation Rating Officers in your region. This memorandum will also be available on the FDA Web site at http://www.fda.gov/food at a later date and should be widely distributed to State Veterinarians, State Veterinary and Pharmacy Boards, Veterinarian Professional Associations, representatives of the dairy industry and other interested parties.

If you would like an electronic version of this document prior to it being available on the CFSAN Web Site, please e-mail your request to Robert.Hennes@fda.hhs.gov

CAPT Robert F. Hennes, RS, MPH, Chief
Milk Safety Branch