Food & Drink / Compounds / Chlortetracycline

Chlortetracycline in food: ingestion safety

Moderate risk

(People-specific data is limited; this page draws from human adult context.) Chlortetracycline (Aureomycin) was the first tetracycline antibiotic discovered (1948, Benjamin Duggar). Widely used in animal feed for growth promotion and disease prevention/treatment in cattle, swine, and poultry. Primary human health concern is antimicrobial resistance (AMR) — subtherapeutic antibiotic use in livestock selects for tetracycline-resistant bacteria transferable to humans via food chain and environmental pathways. FDA Veterinary Feed Directive (VFD) rule (2017) requires veterinary oversight for medically important antibiotics in feed. Direct toxicity low: oral LD50 rat >10,000 mg/kg. Codex MRLs established for animal tissues.

What is chlortetracycline?

Also known as: CTC, Aureomycin, Biomycin, 7-chlorotetracycline.

CAS number
57-62-5
Molecular formula
C22H23ClN2O8
Molecular weight
478.88 g/mol
SMILES
CC1(C2C(C3C(C(=O)C(=C(C3(C(=O)C2=C(C4=C1C=CC=C4O)O)O)O)C(=O)N)N(C)C)O)O
PubChem CID
54675779

Risk for people

Moderate risk

Chlortetracycline (Aureomycin) was the first tetracycline antibiotic discovered (1948, Benjamin Duggar). Widely used in animal feed for growth promotion and disease prevention/treatment in cattle, swine, and poultry. Primary human health concern is antimicrobial resistance (AMR) — subtherapeutic antibiotic use in livestock selects for tetracycline-resistant bacteria transferable to humans via food chain and environmental pathways. FDA Veterinary Feed Directive (VFD) rule (2017) requires veterinary oversight for medically important antibiotics in feed. Direct toxicity low: oral LD50 rat >10,000 mg/kg. Codex MRLs established for animal tissues.

Regulatory consensus

3 regulatory and scientific bodies have classified Chlortetracycline. The classifications differ — that's the data.

AgencyYearClassificationNotes
FDA CVM2017Approved veterinary drug; Veterinary Feed Directive (VFD) required since 2017 for use in feed
EU2006MRL established for food-producing animals; growth promotion use banned since 2006 (Regulation 1831/2003)
WHO2019Highly important antimicrobial (not critically important) for human medicine

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where you encounter chlortetracycline

  • Animal Feed
  • Food
  • Environment

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Chlortetracycline:

  • Probiotics and prebiotics
    Trade-offs: Less consistent growth response. No AMR concern. Increasing adoption in EU post-antibiotic growth promotion ban.
    Relative cost: Variable
  • Improved biosecurity and management
    Trade-offs: Capital investment required. Reduces need for prophylactic antibiotics.
    Relative cost: Higher upfront, lower long-term

Frequently asked questions

Why do regulators disagree about chlortetracycline?

Chlortetracycline has been classified by 3 agencies including FDA CVM, EU, WHO, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.

See Chlortetracycline in the food app

Look up products containing chlortetracycline, compare to alternatives, and explore the full data record.

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Sources (2)
  1. FDA Veterinary Feed Directive Final Rule (2017) — fda
  2. WHO Critically Important Antimicrobials List (6th revision) — who

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →