Iodine concentration in Polish consumer milk

The aim of this study was monitoring the iodine concentration in Polish consumer milk in the years 2011-2012. The test material used in this study consisted of consumer UHT pasteurized milk with extended shelf life. Six randomly selected cartons of milk with different fat content (from 0.5% to 3.2%) were each purchased from large-sized stores located in 16 cities during the summer and in 13 cities during the cow’s winter feeding period. In total, 167 milk samples were collected. During the summer season, the milk’s iodine content averaged 143 μg iodine kg^-1 and ranged from 103 to 196 μg iodine kg^-1 (n=96 samples), with a standard deviation (SD) of ±31 and coefficient variability (CV) of 44%. During the winter season, the milk’s iodine content averaged 183 μg iodine kg^-1 and ranged from 141 to 236 μg iodine kg^-1 (n=77 samples), with a standard deviation (SD) of ±5 and coefficient of variability (%) (CV) of 26%. Iodine levels in Polish consumer milk increased from the last monitoring (2007-2008) from 100 to 143 μg iodine kg^-1 in the summer season, and from 147 to 183 μg iodine kg^-1 in the winter season (increases of 47% and 24%, respectively).