Antibiotic Residues in Cattle Reported to Be Raised Without Antibiotics

Area of Science:

• Food safety and veterinary drug residue analysis.
• Agricultural policy and regulatory compliance.

Background:

• The U.S. Department of Agriculture's Food Safety and Inspection Service (FSIS) issued revised guidance in 2019 for "raised without antibiotics" (RWA) labeling.
• A 2022 study by Price et al. indicated that 15% of RWA-labeled cattle had antibiotic residues in urine samples, raising concerns about the accuracy of RWA claims.

Purpose of the Study:

• To independently assess the prevalence of antibiotic drug residues in kidney and liver tissues of cattle marketed as RWA.
• To verify the effectiveness of current RWA labeling standards and identify potential gaps in oversight.

Main Methods:

• FSIS inspectors collected kidney and liver tissues from 189 RWA cattle across 79 U.S. slaughter establishments.
• Samples were analyzed for 185 veterinary drugs using advanced techniques, including liquid-chromatography coupled with tandem mass spectrometry (LC-MS/MS) and quadrupole high-resolution mass spectrometry (LC-Q/orbitrap).
• Confirmatory analyses were performed multiple times to ensure accuracy of positive results.

Main Results:

• Antibiotic residues were confirmed in tissues from 37 animals (20%), meeting analytical identification criteria in at least two separate analyses.
• Macrolides, tetracyclines, a sulfonamide, and a beta-lactam antibiotic were detected. Multiple antibiotic residues were found in 11 animals.
• Two anthelmintics, fenbendazole and eprinomectin, were also detected in three RWA animals.

Conclusions:

• The study confirms the presence of antibiotic residues in a significant percentage of cattle labeled as RWA, indicating potential non-compliance or issues with the supply chain.
• FSIS has notified the implicated slaughter establishments and recommended root cause analysis and corrective actions to address the findings.
• Further investigation and enhanced monitoring may be necessary to ensure the integrity of RWA labeling claims.