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 0.12μgL^-1 and 1.0μgkg^-1, respectively. The perchlorate concentration in all the samples was above the LOQ. The perchlorate detection data is given as follows: 1.99-6.41μgL^-1 (n=37, mean concentration=4.59±0.17μgL^-1) for dairy milk and 1.49-33.3μgkg^-1 (n=26, mean concentration=7.83±0.22μgkg^-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.