Figure 2

Bacterial growth, Salmonella invasion and TER across HT29-MTX monolayers are affected by experimental and environmental factors. Values correspond to means ± SD (error bars) calculated for effluents of R1, R2 and R3 in F1 and F2 during the last 3 days of each experimental period (Figure 1; N = 9 for Bif, N = 6 for Stab, Sal and Ecol, N = 3 for Inulin). (A) Salmonella, E. coli L1000 and B. thermophilum RBL67 counts measured by plate counts and real-time qPCR analyses, respectively. Counts of major intestinal bacterial groups were presented previously [15]. (B) Invasion and adhesion ratios, expressed as the percentage of invaded and adhered Salmonella related to the total number present in effluents. (C) Efficiency of Salmonella to invade HT29-MTX cells, expressed as the percentage of cell-associated Salmonella. (D) TER across HT29-MTX cell monolayers measured 1-3 h after incubation with reactor effluents, expressed as ratio to values measured with samples of initial model stabilization periods (Stab). Values reported for subsequent experimental periods and connected with an asterisk are significantly different with the Tukey-Kramer-HSD test (*P < 0.05; **P < 0.01).