FIGURE 4.
Effect of P. freudenreichii (PF) CFCS on (A) S. Heidelberg (B) L. monocytogenes, and (C) E. coli O157: H7. TSB containing S. Heidelberg, L. monocytogenes, or E. coli O157: H7 (106 CFU ml−1) were treated with 5, 10, 15, or 20% (v/v) of cell-free culture supernatant (CFCS) of PF. The pH of TSB was adjusted to match the pH of treatments having CFCS were inoculated with the respective pathogen and used as positive controls (CTRL) for each CFCS concentration. The pathogen survival was determined by determining optical density (OD = 600 nm) after incubating samples at 41°C for 24 h (n = 6; ∗P < 0.05). Bacterial counts were represented as OD600 ± standard error.