TY - JOUR
T1 - Specificity of assays used by regulatory agencies to detect antibiotic residues in tissues of culled dairy cows
AU - Payne, Michael
AU - McBride, Michael D.
AU - Utterback, William W.
AU - Breitmeyer, Richard E.
AU - Alberg, Lael
AU - Martin, Dave
AU - Cullor, James S
PY - 1999/4/1
Y1 - 1999/4/1
N2 - Objective - To determine percentage of false-positive test results for assays used by regulatory agencies to detect antibiotic residues in tissues. Design - Prospective study. Animals - 426 dairy cows. Procedure - Dairy cows scheduled for culling that were identified as being unlikely to have antibiotic residues in tissues on the basis of strict inclusion criteria were used. A sample of kidney obtained from each cow at slaughter was tested on-site, using the swab test on premises (STOP; 97 samples) or the fast antibiotic screening test (FAST; 329 samples). Frozen samples (n = 1,278) of liver, muscle, and kidney were thawed and retested at a federal laboratory, using the same screening assays. Kidney and liver samples (n = 852) were also tested using the 7-plate bioassay confirmation test used for confirmation and identification of antibiotic residues. Results - Results of screening assays performed on-site were negative. When frozen samples were retested, 20 (12 liver, 7 kidney, and 1 muscle) had positive FAST results, but none had positive STOP results. Of the samples tested with the 7-plate bioassay confirmation test, 4 liver samples had results indicating a tetracycline (n = 3) or an unidentified microbial inhibitor (1) as a residue. Clinical Implications - Results suggest it is unlikely that regulatory action will be taken against producers sending untreated cattle to market. However, because results of the FAST and 7-plate bioassay confirmation test were positive when applied to frozen tissue, use of assays based on microbial inhibition may not be valid for confirmation of residues.
AB - Objective - To determine percentage of false-positive test results for assays used by regulatory agencies to detect antibiotic residues in tissues. Design - Prospective study. Animals - 426 dairy cows. Procedure - Dairy cows scheduled for culling that were identified as being unlikely to have antibiotic residues in tissues on the basis of strict inclusion criteria were used. A sample of kidney obtained from each cow at slaughter was tested on-site, using the swab test on premises (STOP; 97 samples) or the fast antibiotic screening test (FAST; 329 samples). Frozen samples (n = 1,278) of liver, muscle, and kidney were thawed and retested at a federal laboratory, using the same screening assays. Kidney and liver samples (n = 852) were also tested using the 7-plate bioassay confirmation test used for confirmation and identification of antibiotic residues. Results - Results of screening assays performed on-site were negative. When frozen samples were retested, 20 (12 liver, 7 kidney, and 1 muscle) had positive FAST results, but none had positive STOP results. Of the samples tested with the 7-plate bioassay confirmation test, 4 liver samples had results indicating a tetracycline (n = 3) or an unidentified microbial inhibitor (1) as a residue. Clinical Implications - Results suggest it is unlikely that regulatory action will be taken against producers sending untreated cattle to market. However, because results of the FAST and 7-plate bioassay confirmation test were positive when applied to frozen tissue, use of assays based on microbial inhibition may not be valid for confirmation of residues.
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M3 - Article
C2 - 10200802
AN - SCOPUS:0033113473
VL - 214
SP - 1048
EP - 1050
JO - Journal of the American Veterinary Medical Association
JF - Journal of the American Veterinary Medical Association
SN - 0003-1488
IS - 7
ER -