Figure 4.
Chlorine stress induces Vero-cytotoxicity of non-O157 Shiga toxin-producing Escherichia coli (STEC). Vero-cytotoxicity was assessed using lactase dehydrogenase assay of Vero cells treated with supernatants of STEC cells. (A) Supernatants were collected every 12 h from STEC for 48 h. (B) Supernatants were collected after 24 h of growth. Vero-cytotoxicity was determined and normalized by each cell density population. The results are the average of three independent experiments. *P < 0.05.