Laboratory evaluation of the charm farm test for antimicrobial residues in meat

Charm Farm Tests were applied to 54 muscle and 44 kidney bovine samples, and 95 muscle and 90 kidney porcine samples collected for Canada's national meat inspection program from animals suspected of containing antimicrobial residues. The assays were run in conjunction with Agriculture and Agri-food Canada's routine confirmation analyses for suspect samples collected at federally inspected packing plants. When the bovine and porcine results were combined, 19% of the kidney and 8% of the muscle results were false negatives. Using the Charm Farm Test to screen only the kidney samples would have resulted in 100% identification of the muscle samples that were found to contain violative levels of drug residues. One percent of the kidney and 16% of the muscle results were false positives, on the basis of the results of the confirmatory tests. Minimum detectable levels found in fortified (i.e., artificially contaminated) muscle and kidney with the Charm Farm Test for ceftiofur, chlortetracycline, oxytetracycline, tetracycline, erythromycin, gentamycin, neomycin, penicillin G, streptomycin, sulfamethazine, sulfadimethoxine, tylosin, tilmicosin, and trimethoprim were similar to those claimed by the manufacturer. Minimum detectable levels for the Charm Test II (dihydro)streptomycin and erythromycin receptor assays are reported for fortified muscle and kidney to provide an indication of the relative sensitivities of the Charm Farm Test and the Charm II Tests for these compounds. To further assess the Charm Farm Test's potential as a replacement for existing tests in packing plants, parallel testing needs to be conducted on fresh tissues in a plant environment