Elemental dynamics in human milk: Composition, Holder pasteurization effects, and variability by maternal diet and lactation month

Holder pasteurization is routinely applied in human milk banks to ensure microbiological safety, although its impact on trace elements remains insufficiently described. This study aimed to assess pasteurization effects and variability associated with maternal diet and lactation month in human milk from Uruguayan women. Two analytical methods based on microwave plasma atomic emission spectrometry (MP AES and HG–MP AES) were optimized and validated. Limits of quantification ranged from 0.0018 to 0.014 mg L⁻¹, and trueness was verified using reference materials and spiked samples. In raw human milk samples from a Uruguayan milk bank, mean concentrations in colostrum (n=10) and mature milk (n=30) (mgL⁻¹) were: 0.0042/0.0036 (arsenic), 0.45/0.40 (copper), 2.5/1.9 (iron), 0.0030/0.0020 (lead), 0.0164/0.0132 (selenium), and 6.2/4.5 (zinc). Pasteurization caused significant losses only for selenium (up to 10.4% in colostrum, p