Figure 5.

Persistence of Escherichia coli O157:H7 (A) and Salmonella enterica Typhimurium 14028s (B) varies in 2.5- to 3-week-old plants of lettuce genotypes after syringe inoculation. The second leaf was infiltrated with 1 x 10⁶ CFU/mL bacterial inoculum. Leaves were surface sterilized prior to quantification of the bacterial population in the intercellular space. Results are shown as the average of three independent experiments (n = 3 ± standard error). Pairwise mean comparison (bacterial population at day 0 versus day 10) was performed with two-tail Student’s t-test (ns, not significant, *p < 0.05, **p < 0.01, and ***p < 0.001).