Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2014
Publication Date: 7/16/2014
Publication URL: http://handle.nal.usda.gov/10113/59453
Citation: Shelver, W.L., Lupton, S.J., Newman, D.J., Larsen, S., Smith, D.J. 2014. Depletion of penicillin G residues in heavy sows after intramuscular injection. Part II: Application of kidney inhibition swab tests. Journal of Agricultural and Food Chemistry. 62(30):7586-7592. Interpretive Summary: A commercially available on-site antibiotic test, the kidney inhibition swab (KIS™ Test), has recently been adopted by the USDA Food Safety and Inspection Service (FSIS) to be used at slaughter plants. The KIS™ test was used in this study to determine the decrease of penicillin G from kidney, muscle, serum, and urine of heavy sows after injection of penicillin G procaine into their neck muscle. Penicillin G was depleted most rapidly from liver and muscle but kidney and urine were depleted slowly. Because of its slow depletion, kidney was the most sensitive tissue for detecting penicillin G residues on-site. However, kidney residues were a poor predictor of penicillin G residues in muscle. These data along with other studies suggest that the recommended 15-day withdrawal period for penicillin off-label usage is insufficient for residues to deplete to non-detectable levels in kidney. The KIS™ test indicated the probability that greater than 39 days would be required for residues to deplete sufficiently to ensure that treated animals be free of penicillin G in kidney prior to slaughter. The data indicate that urine would be a very useful for on-farm or pre-slaughter on-site test with which veterinarians or pork producers could predict the presence of kidney penicillin G residues.
Technical Abstract: Sows (n = 126; 228 ± 30.1 kg) were administered daily IM doses of penicillin G procaine (33 000 IU/kg bw; 5× the label dose) for 3 consecutive days using three different administration patterns. Within treatment, six sows each were slaughtered on withdrawal day 5, 10, 15, 20, 25, 32, and 39. Tissues (injection site, kidney, liver, skeletal muscle) or body fluids (serum and urine) were screened for penicillin G using the KIS test, recently adopted by the USDA Food Safety and Inspection Service. The IM administration patterns had no discernible effect on penicillin G depletion. Residues were depleted more rapidly from liver and skeletal muscle and more slowly from kidney and urine. Kidney was the most sensitive and suitable tissue for detecting penicillin G residues on-site, with two positive results after a 39-day withdrawal period. Urine was the most suitable ante-mortem surrogate to predict the results of kidney tests.