Suitability of brilliant black reduction tests for the detection of antibiotics in buffalo and horse milk

The brilliant black reduction test (BRT) is a first and rapid screening test routinely used across the German dairy industry for the detection of antimicrobial substances, especially antibiotics, in cow's milk samples. This study aimed to determine if the three test systems BRT Inhibitor Test, BRT MRL-Screening Test and BRT hi-sense can also be applied to buffalo and horse milk. For buffalo milk, the detection limits of all antibiotics under investigation were at or below the European maximum residue levels (MRL). Previous freezing of the antibiotics in buffalo milk showed comparable results. While the BRT hi-sense is not recommended for horse milk, detection limits at or below the MRL were reached with the BRT Inhibitor Test and/or the BRT MRL-Screening Test for penicillins, neomycin, gentamicin, as well as streptomycin (BRT MRL-Screening Test only). In general, it must be noted that the incubation times of the test systems need extending compared to cow's milk and that horse milk must be heated before application.