Occurrence of several main antibiotic residues in raw milk in 10 provinces of China.

In the present study, 199 raw milk samples were analysed for beta-lactams, tetracyclines, sulfonamides and quinolones. They were obtained from collection tanks of milk routes in 10 provinces of China. The occurrence and concentration range of the four antibiotics were investigated by competitive enzyme-linked immunosorbent assay methods. At the detectable level, 0.5%, 47.2% and 20.1% of samples were positive for beta-lactams, quinolones and sulfonamides, respectively. No sample was positive for tetracyclines. Beta-lactams were positive only in Beijing while quinolones and sulfonamides were positive in all provinces. One (0.5%) sample for beta-lactams was above the maximum residue limits (MRLs, regulated by EU, CAC and China). The maximum concentrations for sulfonamides and quinolones were 16.28 µg kg⁻¹ and 23.25 µg kg⁻¹ which were under their maximum residue limits. More precaution should be taken on antibiotic controls because of the high detection rate of some antibiotics.