Retention of oxytetracycline residues in cooked channel catfish fillets

Catfish (mean body weight 0.87 kg) treated with oxytetracycline (OTC) at 150.0 mg/kg body weight for 10 days and slaughtered 18 hr after last feeding had higher OTC residue levels than those receiving OTC at 37.5 or 75.0 mg/kg. Individual differences in feed uptake and metabolism of OTC among catfish might contribute to variability in residue. Baking and smoking at 190 degrees C were more effective in reducing OTC residues than frying. The reduction appeared to be related to the final temperature reached and duration of cooking. Results confirmed that common cooking procedures may not completely degrade OTC in catfish fillets.