Shiga Toxin-Producing in the Long-Term Survival Phase Exhibit Higher Chlorine Tolerance and Less Sublethal Injury Following Chlorine Treatment of Romaine Lettuce.

The extent of chlorine inactivation and sublethal injury of stationary-phase (STAT) and long-term survival-phase (LTS) cells of Shiga toxinproducing (STEC) and in a lettuce postharvest wash model was investigated. Four STEC strains were cultured in tryptic soy broth supplemented with 0.6% (w/v) yeast extract (TSBYE; 35°C) for 24 h and 21 d to obtain STAT and LTS cells, respectively.