Validazione di un test rapido per la rilevazione di antibiotici nel latte ovino

The study was designed to achieve evaluation and validation of a rapid screening test in ewe milk. Betastar® Combo 3.0 reveals antibiotics of betalactams and tetracyclines classes. Antibiotics-free milk samples from Sarda ewes, throughout three sampling trials, were commingled with Penicillin, Amoxicillin, Cefazolin and Oxytetracycline. Spiking concentrations were set on the European Union maximum residue limits (MRLs). Betastar® Combo 3.0 has thee lines of detection on the dipstick: the first for betalactams, the second as control line and the third for tetracyclines. Test is negative when the ratio between intensities of test lines and control line is higher than 1.0 while it is positive when it is lower or equal than 1.0. Results were achieved and analysed with a statistical software. A total amount of 180 negative control samples were tested and they were always negative according to antibiotics, trials and ewes. Results for Penicillin showed a satisfactory detection limit from 2 to 3 μg/kg (MRL is 4 μg/kg). As regards Amoxicillin and Oxytetracycline, results were almost always lower than the MRLs (4 and 100 μg/kg, respectively) but in one case out of nine detecting concentration was slightly higher. Detection limit for Cefazolin was higher than its specific MRL (50 μg/kg). In conclusion, Betastar® Combo 3.0 could be a suitable method in order to achieve a rapid detection of some antibiotics residues in ewe milk at farm and industrial levels.