Hydroxymethylfurfural (HMF) is an organic compound found in low levels (approximately 15mg/kg) in honey. It is caused by the dehydration of some sugars and levels can increase dramatically following heat treatment of honey to destroy contaminants or to reverse crystallisation. Unfortunately, TMF has been shown to exhibit cytotoxic, genotoxic, mutagenic, and carcinogenic effects. The European Union has set limits of 40mg/kg.
Currently three tests are recommended by the International Honey Commission to determine levels of TMF. The two most commonly used tests, a UV spectroscopy and an HPLC method were compared by Italian scientists from the Università Politecnica delle Marche and the Agenzia Servizi Settore Agroalimentare delle Marche (ASSAM). They found that the levels detected above 1mg/kg for the two methods were comparable but that the HPLC method showed greater precision. Both methods were inaccurate for determining levels below 1mg/kg.
The paper is available from the Journal of Food Science website.