SELENIUM AND IODINE CONTENT IN SHEEP MILK FROM FARMS IN CENTRAL AND EAST BOHEMIA

Selenium and iodine content was analyzed in sheep milk from 4 and 6 different farms in central and east Bohemia. Samples had been collected monthly in two years period. Iodine was determined by high performance liquid chromatography (HPLC) with electrochemical detection and selenium using electrothermal atomization atomic absorption spectrometry (ETA-AAS) with hydride generation. The average levels of selenium and iodine in milk from small family farms were 39.09 ± 12.77 μg/kg and 47.99 ± 13.24 μg/kg, respectively. On the big farm focused on commercial breeding the average values were significantly higher (576.7 ± 261.2 μg/kg). Significant differences in levels of both elements were found between summer and winter period. In the winter period, the average level of selenium was 68.33 ± 43.75 μg/kg and in the summer period 30.67 ± 8.31 μg/kg. Levels of iodine show the same tendency: 72.42 ± 64.37 μg/kg in the winter and 37.84 ± 16.09 μg/kg in the summer period. Moderately strong correlation (r = 0.39) was found between selenium and iodine content in sheep milk. The comparison of iodine and selenium content in sheep milk and whey implies that 6 9.4% of iodine is transferred to the whey fraction