Use of a Simple Fermentation Test to Detect Antibiotic Residues in Milk1,2

Abstract

The sensitivity of a local Lebanese yogurt culture to different antibiotics was checked, using either a fresh or a freeze-dried culture. Laban fermentation was significantly affected by 0.005 IU of penicillin/ml, 1μg of streptomycin/ml, 1μg of dihydrostreptomycin/ml, 10 μg of chloramphenicol/ml and a level of oxytetracycline between 0.05 and 0.5 μg/ml. Although the method was not standardized, it was used to check 858 milk samples in Lebanon of which 11.20% were found to contain lactic acid bacterial inhibitory substances.