Addition of surfactin and other surfactants to a preformed biofilm accelerates biofilm dispersal. After S. enterica had reached an OD630 of ≈0.15 to 0.2, the indicated surfactants were gently mixed into the cultures in microtiter wells. Samples were harvested, and either growth (A), as determined by OD630, or biofilm levels (B), as measured by OD550 of crystal violet-stained material, were analyzed at the indicated time points. ⧫, no treatment; ○, 100 μg of surfactin; ×, 0.25% Tween 80; ▪, 100 μg of rhamnolipid; ▴, 0.2% SDS. The data are means of triplicate samples monitored on the same day.