Adulteration of honey:relation between microscopic analysis and delta C-13 measurements

Upon routine microscopic analysis of some honey samples, parenchyma cells, single rings of ring vessels and epidermal cells are found. These cells originate from the sugar cane stem. We investigated whether there was a relation between these plant fragments and the delta C-13 value of honey. 17 honey samples and 6 cane sugar samples were analyzed. Microscopic analysis of the samples was done quantitatively by counting the parenchyma cells, rings, and epidermal cells present in 10 g of the sample using polarized light microscopy. Also the repeatability of the microscopic analysis was determined by calculating the standard deviation of the values from the processing and examination of 8 sub-samples from one honey sample For all honey samples in this study, it was found that if more than 150 parenchyma cells and/or 10 rings in 10 g were detected, the samples were adulterated with C-4 sugars (from sugar cane or corn) according to the delta C-13 method. Lower microscopic counts indicated honey with suspected adulteration below 7%, the limit of detection of the delta C-13 method. Overall, the microscopic procedure was a good screening method for the detection of adulteration of honey with cane sugar products.