Evaluation of HMF as marker for the honey shelf-life.

Samples of orange and eucalyptus honey were pasteurised at 70 degrees C for different times and then stored for ten months at 25 degrees C. HMF content, diastase activity, pH and total acidity were determined on fresh honeys, on pasteurised honeys and periodically on stored honey samples. Pasteurisation did not induce negative effect on HMF content in orange and eucalyptus honeys. After ten months of storage orange honey shows a HMF content above the fixed EU limit of 15 mg/kg, while eucalyptus honeys, during storage, show a very variable trend of HMF content which prevented the quality of this honey to be evaluated.