Detection and Quantification of 41 Antibiotic Residues in Gilthead Sea Bream (Sparus aurata) From Aquaculture Origin, Using a Multiclass and Multi-residue UHPLC-MS/MS Method

Aquaculture is one of the worldwide strategic development fields, and its importance is evident in its significant worldwide growth in the last decades. This growth is associated with the implementation of intensive and semi-intensive production methods, with the use of antibiotics in order to prevent the emergence and spread of infectious diseases in fish. This practice constitutes a real public health problem, not only due to the presence of antimicrobial residues in edible tissues, which can cause allergic reactions in hypersensitive individuals, but also due to the emergence of bacterial resistance. Consequently, the Regulatory Agencies have established maximum residue limits (MRLs). In the present study, a validated multiclass multi-residue ultra-high-performance liquid chromatography coupled with mass spectrometry in tandem methodology was used for the determination of 41 antibiotics from seven different classes—sulfonamides, trimethoprim, tetracyclines, macrolides, quinolones, penicillins and chloramphenicol—in 29 samples of gilthead sea bream of aquaculture origin, purchased in Portugal. The analysed samples showed that, in eight of them, antibiotic residues were present, three being of doxycycline—antibiotic for which no MRL is established—that was detected in concentrations ranging from 0.35 to 0.61 μg kg−1. Other antibiotics were also detected and quantified and their concentrations were below the MRL established by the European legislation.