Development of an analytical protocol for detecting antibiotic residues in various foods

Medicines such as antibiotics and hormones have been widely used for treating diseases in animals. As more antibiotics are needed to prevent various diseases that occur, not only in domestic animals, but also in imported livestock, a quick and robust analytical method is required for detecting antibiotic residues. In this study, agricultural and fishery products, including beef (n = 148), pork (n = 78), chicken (n = 88), eel (n = 70), flatfish (n = 17), armorclad rockfish (n = 18), sea bream (n = 18), perch (n = 18), and oyster (n = 4) were obtained from local markets in different areas of Korea. A total of 13 antibiotics, including tetracycline, macrolide, penicillin, aminoglycoside, polyester, peptide, and chloramphenicol types, were analyzed by a microbial assay and high performance liquid chromatography (HPLC). In the microbial assay, 34 of the 459 screened samples had possible antibiotic residues. The antibiotic concentrations of the 34 samples were analyzed using HPLC with UV and fluorescence detection. The levels of oxytetracycline in pork and eel were 0.01 and 0.05 mg/kg, respectively. In eel and oyster, the concentrations of ampicillin were 0.4 and 0.32 mg/kg, respectively. In beef, the concentration of tylosin was 0.05 mg/kg. The levels of oxytetracycline and tylosin were below the Korean Food Code’s recommended maximum residue limit (MRL). A maximum residue limit for ampicillin in fishery products, however, has not been established in Korea. These data indicate that an MRL for ampicillin should be set for sea foods and regulated by the Korean authorities.