Iodine content in bulk tank milk samples in relation to dairy farm size

Abstract

The aim of this study was to compare the iodine content in raw milk from organic and conventional dairy farms of different sizes. Milk samples were collected between 2012 and 2013, and the iodine content was determined by a Sandell-Kolthoff reaction after dry alkaline digestion of the milk samples. Comparing the iodine content in raw milk samples from small sized dairy farms (116.76 ± 46.29 μg/l) and large sized dairy farms (173.70 ± 35.42 μg/l), a significant difference in iodine content was observed (P ≤ 0.05). The lowest values were found in small and medium dairy farms, 45.30 μg/l and 40.46 μg/l, respectively. High variability (112.92 ± 94.74 μg/l) in the iodine content was detected in raw milk from medium sized dairy farms. When considering milk samples from organic dairy farms (119.29 μg /l ± 40.37) vs. conventional dairy farms (136.55 μg/l ± 42.91), no significant difference was detected. These results indicate higher iodine content in milk from large dairy farms regardless of conventional or organic farming methods.