Abstract

The purpose of this study was to determine the effects of different cooking processes like boiling, roasting and microwaving on sulfadiazine + trimethoprim residues in edible tissues of broiler chickens. Each of chicks was fed by water and food with 0.05% of sulfadiazine + trimethoprim in their drinking water for consecutive 5 days. After the 5th day of the drug administration, they were killed and breast muscle; liver and gizzard were sampled aseptically from each carcass. The residue was analyzed using microbial inhibition test by plates seeded with Bacillus subtilis. The positive raw samples cooked by various cooking procedures (roasting, boiling and microwaving). Then, we surveyed cooked samples for the present of residue. The results show the reduction in concentration of sulfadiazine + trimethoprim residue after different cooking processes. The most reduction of sulfadiazine + trimethoprim residues in cooked muscle samples related to microwaving process and a part of residue excreted from tissue to cooking fluid in boiling process. Muscle samples had the most resistance to residue reduction rather than other tissues in boiling and roasting processes. The reduction effect of all cooking processes on liver and gizzard samples was greater than muscle samples and the inhibitory zone around all cooked liver and gizzard samples were not detectable. Regarding to the results of this study, we can concluded that cooking processes do not guarantee a full break-down of these drugs present in condemned animals. Between the various agents affecting antibiotics residue after cooking process, cooking time and temperature can play major role about antibiotic residue reduction.

Key words: Cooking, sulfadiazine, trimethoprim, residue, edible tissue, broiler.