Perchlorate in dairy milk and milk-based powdered infant formula in South Korea

Perchlorate has been detected in dairy milk and milk-based powdered infant formula samples from many different provinces of South Korea. A total of 37 dairy milk samples from 12 different brands and 26 milk-based powdered infant formula samples from four different brands were tested for the presence of perchlorate. These brands and their products, which are analyzed in this study, cover over 95% of the dairy milk and milk-based powdered infant formula market share in South Korea, which has a population of approximately 50 million inhabitants. Perchlorate was explicitly detected by ion chromatography tandem mass spectrometry; the limit of quantification (LOQ) for dairy milk and milk-based powdered infant formula was 0.12 μg L−1 and 1.0 μg kg−1, respectively. The perchlorate concentration in all the samples was above the LOQ. The perchlorate detection data is given as follows: 1.99–6.41 μg L−1 (n = 37, mean concentration = 4.59 ± 0.17 μg L−1) for dairy milk and 1.49–33.3 μg kg−1 (n = 26, mean concentration = 7.83 ± 0.22 μg kg−1) for milk-based infant formula. This study provides increasing evidence that perchlorate commonly occurs in dairy products, presumably as the result of perchlorate intake by dairy cattle from water and feed.