Degradation of incurred tylosin to desmycosin--implications for residue analysis of honey.

As a result of the application of tylosin to honey bee colonies for the control of American foulbrood disease, antibiotic residues may exist in honey destined for human consumption. It has been recognized that the parent compound, tylosin A, degrades in acidic media such as honey to yield the antimicrobially active degradation product, desmycosin. Data is presented documenting levels of incurred tylosin and desmycosin in honey resulting from simulated therapeutic applications of a commercial formulation of tylosin during the fall. It is demonstrated that honey destined for human consumption should be analyzed for both tylosin A and desmycosin (tylosin B) rather than the parent antibiotic alone. An analytical method that permits the simultaneous determination of tylosin A and desmycosin in honey using liquid chromatography-tandem mass spectrometry is also presented.