EVALUATION OF A MULTIPLE BIOASSAY TECHNIQUE FOR DETERMINATION OF ANTIBIOTIC RESIDUES IN MEAT WITH STANDARD SOLUTIONS OF ANTIMICROBIALS

A multiple bioassay technique (FSIS-USDA) has been evaluated with stan dard solutions of 38 antibiotics and sulphonamides. Activity patterns at five levels were obtained when antibiotic solutions were assayed on seven plates prepared with different media and microorganisms. A diff erent activity pattern was obtained for the main antibiotic groups: te tracyclines, beta-lactam antibiotics, macrolides and aminoglycosides. Sulphonamides were not detected at levels under 100 mu g/ml. This tech nique, as a post-screening test for antibiotic residues, can be used a fter a screening test to identify antibiotic groups to which more spec ific techniques can be applied for full identification and quantificat ion.