Because no maximum residue limits (MRLs) have been set, the goal of analytical methods has to be to reach a lowest possible detection limit. A detection of the drugs at “any” concentration should be sufficient to point to a violation of the law. Nevertheless, it has to be noted that contamination may not only occur from deliberate, direct misuse of the drugs but also from contaminated feed, environmental contamination (housing at the slaughterhouse) or transfer between animals [2].