Effect of pasteurization on different antibody components. Two breast milk samples (A and D) were thawed and IgA isolated by passage over a Peptide M column. Each sample was split in two then treated by Holder pasteurization (62.5°C for 30 min) or left on ice for 30 min. Control samples were used just after Peptide M isolation. (A) Samples were boiled in Laemmli buffer and run on an LDS-PAGE gel (4–15% Gradient Acrylamide gel). Samples were normalized to protein content after pasteurization. (B) “D” samples were transferred onto nitrocellulose and blotted for heavy chain (right) or light chain (kappa; left). Samples were normalized to protein content after pasteurization. HP, Holder pasteurization; Ctrl, no treatment; SecF, SeF; IgAHC, IgA heavy chain; LC, light chain; MW, molecular weight. Source data are available for this figure: SourceData FS4