Multiantibiotic residues in commercial fish from Argentina. The presence of mixtures of antibiotics in edible fish, a challenge to health risk assessment

•First simultaneous determination of 46 antibiotics in fish from South America.•Commercially available fish in Argentina presents a wide variety of antibiotics.•At least one antibiotic was detected in the total of the sampled fish.•Antibiotics not allowed (chloramphenicol, furazolidone and nitrofurantoin) detected.•Doxycycline, oxytetracycline, sulfaguanidine and sulfamethazine exceeded MRL.