Activated persulfate as a potential sanitizer to ensure food safety

Summary

Activated persulfate, a relatively new advanced oxidation process, was evaluated for its efficacy on inactivation of foodborne pathogens. More than 7 log CFU/mL reductions can be achieved in 120 s for both Escherichia coli O157:H7 and Listeria monocytogenes at appropriate activation conditions. For ferrous activation, the maximum pathogen reduction (7.77 log CFU/mL for E. coli O157:H7 and 7.25 log CFU/mL for L. monocytogenes) was achieved at persulfate to ferrous molar ratio of 1:0.33 when the initial persulfate concentration was set at 40 mmol/L. For alkaline activation, the inactivation efficacy increased with increasing initial sodium hydroxide concentration. The maximum reduction was achieved at 40 mmol/L persulfate with 30 mmol/L sodium hydroxide for E. coli O157:H7 (6.21 log CFU/mL reductions) and at 500 mmol/L persulfate with 350 mmol/L sodium hydroxide for L. monocytogenes (8.64 log CFU/mL reductions). Hydroxyl radical was demonstrated to be the major radical to inactivate both pathogens in ferrous activation while superoxide radical was found to be the major radical to inactivate both pathogens in alkaline activation.

Situation

Fresh fruits and vegetables are essential sources of numerous nutrients, and the fresh produce industry is one of the most important parts of the global food market. However, trends of increasing consumption of fresh produce coincide with increasing cases of foodborne illnesses and outbreaks. Chlorine based sanitizers, such as sodium hypochlorite, are commonly used disinfectant chemicals in the fresh produce industry because of the low cost and high efficacy in pathogen inactivation. However, the production of toxic disinfection by-products (DBPs), such as trihalomethanes, haloacetic acids, and nitrogenous DBPs, during chlorine sanitation pose potential threats to consumers' health. Hence, alternative sanitizers that are effective in pathogen removal with less or no toxic DBPs production are needed to ensure produce safety.

Response

Fresh fruits and vegetables are essential sources of numerous nutrients, and the fresh produce industry is one of the most important parts of the global food market. However, trends of increasing consumption of fresh produce coincide with increasing cases of foodborne illnesses and outbreaks. Chlorine based sanitizers, such as sodium hypochlorite, are commonly used disinfectant chemicals in the fresh produce industry because of the low cost and high efficacy in pathogen inactivation. However, the production of toxic disinfection by-products (DBPs), such as trihalomethanes, haloacetic acids, and nitrogenous DBPs, during chlorine sanitation pose potential threats to consumers' health. Hence, alternative sanitizers that are effective in pathogen removal with less or no toxic DBPs production are needed to ensure produce safety.

Impact

The results indicated that sodium persulfate activated by ferrous sulfate and sodium hydroxide can effectively inactivate E. coli O157: H7 and L. monocytogenes. The persulfate to activator molar ratios played an important role in determining the overall pathogen inactivation efficacy. For ferrous activation, insufficient or excess amount ferrous sulfate will lead to reduced pathogen inactivation efficacies. For alkaline activation, the inactivation efficacy can be improved by higher basicity. Hydroxyl radical was determined to be the major contributing radical in ferrous activation while superoxide radical was determined to be the major contributing radical in alkaline activation to inactivate E. coli O157: H7 and L. monocytogenes. Alkaline activation can be advantageous to ferrous activation due to the prolonged activation period. Thus, activated persulfate can be used as a novel sanitizer for fresh produce sanitation.

State Issue

Food Safety & Quality

Details

• Year: 2020
• Geographic Scope: National
• County: Spalding
• Location: Georgia Station, Griffin
• Program Areas:
  • Agriculture & Natural Resources