Figure 2.

Inhibition of C. perfringens by cell-free supernatants with and without pH neutralization, obtained from L. acidophilus and L. fermentum. Agar well diffusion assay was performed and the inhibition zone was assessed visually (A). Lactobacilli supernatants were collected after 24 or 48 h of incubation. Central wells were filled with sterile MRS broth adjusted to pH 4.2 or standard MRS broth. The colonies of C. perfringens were black in the TSC agar. The growth of C. perfringens in fresh MRS broth supplemented with lactobacilli supernatants was measured by OD₆₀₀ after 24 (B) and 48 (C) hours of incubation. Data are presented as mean ± standard error (n = 3). ^**P < 0.01. La-S, supernatants from L. acidophilus cultures; Lf-S, supernatants from L. fermentum cultures; MRS, Mann-Rogosa-Sharpe medium.