Investigation of Antibiotic Residue, Nitrofuran Compounds, Microbial Properties and Heavy Metal Amount in Rainbow Trout (Oncorhynchus mykiss)

The aim of this study was to determine the pathogenic microorganisms, antibiotic residues, and metal concentrations in rainbow trout (Oncorhynchus mykiss) fillets grown in 3 different regions in Trabzon and to determine their compliance with the limit values determined by national (Turkish Food Codex) and international legislation (Codex Alimentarius commission, European Comission). Of the 46 antibiotic residues and 4 nitrofuran residues searched, none of the fillets were detectable and all were below the maximum residue limit. The highest number of aerobic colony count was found at 3.2 × 104 (A2 location). Enterobacteriaceae<10 cfu/g, Escherichia coli<3 MPN/g and<10 cfu/g, Staphylococcus aureus<10 cfu/g, and Coliform bacteria<3 MPN/g and<10 cfu/g were detected. Listeria monocytogenes, Salmonella spp. Vibrio cholera, and Vibrio parahaemolyticus were not found in any of the locations. Metal concentrations, Pb, Cd, and Hg observed were below the limits set by the legislation. The results show that rainbow trout fillets cultivated in offshore fish farms in 3 different regions are below the maximum limit values specified in national and international regulations in terms of antibiotic residue amount, heavy metal content, and microbiological properties.