Enhanced Chlorine Efficacy against Bacterial Pathogens in Wash Solution with High Organic Loads

Abstract

Chlorine is widely used as a sanitizer in commercial fresh-cut produce wash operations. However, chlorine reacts rapidly with organic materials, leading to potential pathogen survival when chlorine concentration nears depletion. This study evaluated a new process aid, T128, for its capacity to enhance chlorine efficacy against Escherichia coli O157:H7 in solutions with high organic loads. Chlorine solutions were prepared with either T128 or citric acid (control) to adjust pH. Survival of E. coli O157:H7 was assayed during washing of increasing amounts of shredded lettuce, or addition of lettuce juice as organic load. The application of T128 significantly reduced survival of E. coli O157:H7 when free chlorine in solution decreased to levels approaching depletion. In the presence of T128, no pathogen survival was observed with the free chlorine concentration as low as 0.05 mg/L, while 0.4 mg/L free chlorine was required to kill pathogens in the absence of T128 in the wash solution. Practical Applications The foodborne illness outbreaks that plague the fresh-cut produce industry are a testament to the need for a more effective sanitizer to prevent pathogen survival and cross contamination in commercial produce wash systems with large influxes of organic matter. This paper reports the investigation of the effect of a new process aid, T128, on reducing the survival of E. coli O157:H7 in wash solutions in which chlorine is near depletion due to high organic load, and thus the potential to improve the safety margin of fresh-cut process control.