Comparative Examination of the Analysis of β-Lactam Antibiotic Residues in Milk by Enzyme, Receptor–Enzyme, and Inhibition Procedures

摘要

Antibiotic residues in milk are of great concern to dairy farmers, milk processors, regulatory agencies, and consumers. The aim of this study was to compare the screening tests for residue detection in milk with the purpose of choosing the most sensitive test that could prove residue quantities at maximum residue limits (MRL). The Penzyme S, Delvo-X-press β-lactam II, Delvo SP test, and diffusion test were examined. Milk samples (218) were collected from different segments of milk production chain: farms, milk collection points, dairy, and market. The limit of detection (LOD) of all methods for penicillin G, ampicillin, and amoxicillin were within the MRL, except the LOD for cloxacillin (diffusion test and Delvo-X-press), which were above the MRL value of 30 ng/g. Agreement between test results evaluated by kappa statistic for all tests was substantial (κ = 0.61–0.80). We suggest the samples to be examined by Delvo SP test in the dairy. Positive milk samples should be retested by Penzyme S or Delvo-X-press test because of the high probability that residues are β-lactams, and these tests can prove it. By recurrent examining procedure, starting with the milk samples from pickup trucks, bulk milk tanks in collection points, or bulk milk tanks at farm and from individual producers, the specific milk that was contaminated by antibiotics can be traced.