Recent study shows that fumagillin use can contaminate honey with an ingredient called dicyclohexylamine . 

> Fumagillin is extensively used to control nosema disease in apiculture. In the commercial formulation, fumagillin is present as a salt in an equimolar quantity with dicyclohexylamine (DCH). In this study DCH was observed to be significantly more resistant to degradation in honey than fumagillin using LC-MS/MS analysis. 

> Observed half-lives for DCH ranged from a minimum of 368 days when kept at 34oC in darkness, to a maximum of 852 days when stored at 21oC in darkness. A maximum half-life of 246 days was observed for fumagillin in samples kept in darkness at a temperature of 21oC. The observed half-life of fumagillin was estimated to be 3 days when exposed to light at 21oC, and complete decomposition was observed after 30 days under the same conditions. 

> The stability of DCH, combined with its genotoxicity and tumorigenic properties make it an important potential contaminant in honey destined for human consumption.

> The long half-lives observed for DCH in this stability study (ranging from 1 to almost 3 years) indicate that DCH will likely be detectable in honey at higher concentrations than fumagillin for extended periods of time. It is important to remember that DCH and fumagillin are applied in theoretically equimolar amounts when using the current commercial formulations.

> A thorough risk assessment needs to be conducted in order to establish a maximum residue limit (MRL) for both fumagillin, as well as for DCH in honey.

van den Heever, J. P., Thompson, T. S., Curtis, J. M., & Pernal, S. F. (2015). Stability of dicyclohexylamine and fumagillin in honey. To appear in: Food Chemistry.

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