FIG 3.

Destruction of cell membrane of non-acid-adapted or acid-adapted Salmonella Typhimurium (A) or Escherichia coli O157:H7 (B) as determined by the PI uptake assay. Data represent averages for three independent experiments, and error bars indicate standard deviations. The data were normalized by subtracting fluorescence values obtained for untreated cells and against the OD₆₀₀, as follows: (fluorescence value after treatment − fluorescence value for untreated control)/OD₆₀₀. Different uppercase letters for cells grown in the same matrix indicate significant differences (P < 0.05). Different lowercase letters for the same treatment dose indicate significant differences (P < 0.05).