Presence of aflatoxin M1 in white and hard cheese samples from Serbia

The level of aflatoxin M1 (AFM1) in 54 samples of white and hard type of cheese produced in Serbia was investigated using ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). Two methodologies were developed for sample extraction, separately for white and hard type of cheese. The first one involved sample extraction with mixture of acetonitrile/water (86:14, v/v) for white cheese without sample clean-up step. The second method consisted of a sample extraction with dichloromethane/acetone for hard cheese followed by solid-phase extraction (SPE) clean-up by SPE C18 cartridges. The average recoveries of AFM1 from spiked samples at levels of 0.25–0.50 μg/kg, were 73–111% and the precision (RSD) ranged from 7 to 9% with the first method, whilst the average recoveries from samples spiked at levels of 0.125–0.50 μg/kg were 71–80%, with RSD ranged from 4 to 10% for the second method. Due to different matrix effects, the quantification limits were 0.125 and 0.02 μg/kg for white and hard type of cheeses, respectively. samples (13%) exceeded the maximum acceptable level of 0.25 μg/kg has been established for AFM1 in some European countries like Switzerland, France, Austria and Turkey.