Effect of Enprocal D and other digested milk product controls on transepithelial electrical resistance (TEER) (A), tight junction protein-ZO-2 expression (immunofluorescence in confocal microscopy) (B). Caco-2 monolayers (21 day old, differentiated cells) were incubated with 500 μg/ml of test samples and control (no treatment) for 48 hours as indicated. All treatments were performed in triplicate and assay was repeated three times independently with similar results. The effect on epithelial barrier integrity was measured (TEER results in ohms-cm2) and mean ± SD to relative TEER values were calculated with respect to media only controls and plotted. Significant differences (*P, < 0.05) and highly significant differences (**P, < 0.001) between the relative TEER levels as compared to control cells are indicated by asterisks.