Evaluation of three different microbial inhibition tests for the detection of sulphamethazine residues in the edible tissues of rabbits

Ivona Kožárová (1) , Jana Janošová (2) , Dioniz Máté (1) , Soòa Tkáčiková (3)

1 Food Hygiene and Technology
2 Department of Chemistry, Biochemistry and Biophysics
3 State Veterinary Institute Košice

The aim of the present study was to evaluate three microbial inhibition tests (MIT) based on the inhibition of the growth of the test organism, the Four Plate Test (FPT) containing Bacillus subtilis BGA, the Screening Test for Antibiotic Residues (STAR) containing Bacillus stearothermophilus var. calidolactis ATCC 10149, and the Premi®Test containing Bacillus stearothermophilus var. calidolactis, for determining sulphamethazine (SMZ) residues in edible tissues of rabbits after its oral administration up to day 15 of the withdrawal period (WP). A solvent extraction procedure was used to enhance the capability of the tests to detect SMZ residues at or below maximum residue limit (MRL), and para-aminobenzoic acid (PABA) was employed to identify SMZ residues already in the first stage of the residue screening. The presence of SMZ residues in the examined samples was confirmed and quantified by a validated high-performance liquid chromatographic (HPLC) technique. The Premi®Test detected SMZ residues in the muscle and heart tissue until day 9 of the WP and in the liver, lungs and kidneys until day 10 of the WP. The STAR detected SMZ residues in the edible organs of rabbits until day 8 of the WP. The kidneys were positive until day 5 of the WP, the liver until day 4 of the WP and the lungs until day 3 of the WP. No SMZ residues were detected in the muscle and heart. By using the solvent extraction procedure, SMZ residues were detected in the muscle extract until day 10 of the WP and the muscle was positive until day 6 of the WP. No detection sensitivity was observed by using the FPT. After the solvent extraction, SMZ residues were detected in the muscle extract until day 8 of the WP and the muscle was positive until day 3 of the WP. No positive results were detected after the addition of PABA into/onto the agar medium. PABA at the concentration of 10 µg.ml-1 completely reversed the inhibitory activity of SMZ and enabled reliable identification of SMZ in the examined samples. By using the HPLC, SMZ was detected in the muscle samples until day 10 of WP (0.02 mg.kg-1) and in the liver until day 12 of the WP (0.09 mg.kg-1). The results obtained by the HPLC method and the limit of detection (LOD) of screening tests for SMZ (FPT 0.4 µg.ml-1, STAR 0.2 µg.ml-1, Premi®Test 0.05 µg.ml-1) allowed us to state that the most suitable screening tests for the detection of SMZ residues in the edible tissues of rabbits at the level corresponding to MRL of 0.1 mg.kg-1, established for sulphonamides, are the Premi®Test and the STAR in conjunction with the solvent-extraction procedure.

Mots clés: Life Sciences

Ivona Kožárová, Jana Janošová, Dioniz Máté, Soòa Tkáčiková. Evaluation of three different microbial inhibition tests for the detection of sulphamethazine residues in the edible tissues of rabbits. Food Additives and Contaminants, 2009, 26 (07), pp.978-987. ⟨10.1080/02652030902839715⟩. ⟨hal-00573871⟩