Oxytetracycline, tetracycline, chlortetracycline and doxycycline in pasteurised cow’s milk commercialised in Brazil

The aim of this study was to investigate the presence of tetracycline residues in pasteurised cow’s milk using high-performance liquid chromatography coupled with UV/VIS detection to determine the exposure of Brazilian’s population to antibiotic residues. One hundred samples collected from the State of Paraná, Brazil, were analysed. Three of these samples were contaminated at the following concentrations: 121.8 µg·kg⁻¹ for oxytetracycline, 93.5 µg·kg⁻¹ for tetracycline and 134.6 µg·kg⁻¹ for chlortetracycline (61.6 µg·kg⁻¹) and doxycycline (73.0 µg·kg⁻¹). The median tetracycline residue concentration found in the samples was 42.3 µg·kg⁻¹, and the estimated daily intake (EDI) was 0.05 µg Kg⁻¹ bw day⁻¹ in Brazil. These results demonstrate that the occurrence of tetracycline in Brazilian milk was low (3%) and only for 2% above the maximum residue limit, so the risk to the population from the presence of these residues in milk was low (<1% of the acceptable daily intake).