Assay of antibiotic detection limits in cow's milk model samples and comparison of sensitivity of various detection systems (disk diffusion method, Delvotest SP and Penzym S 100).

Abstract

The work was aimed at estimating the detection limits of 21 antibiotics (beta-lactam antibiotics, cephalosporins, aminoglycosides, macrolides and others) by means of three types of detection systems (disk diffusion method with Bacillus stearothermophilus var. calidolactis C 953, Delvotest SP and Penzym S 100) and to verify their sensitivity in the evaluation of the admissible maximum residual limits (MRL). The high sensitivity and the good correlation of results have been achieved mainly by applying the rapid methods such as Delvotest SP and Penzym S 100 versus the less sensitive disk diffusion method.  In the next stage of the work, detection limits of the mutual combinations of antibiotics in milk were estimated. In the model experiment, the synergic effect between ampicillin and oxacillin, cefuroxime and trimethoprim and between cephalosporins (combination of cefazolin with cefoperhazon) was observed.