Effect of Plasma Activated Water on Microbiological Quality and Shelf-life of Strawberries

This study investigated the potential of plasma-activated water (PAW) as a non-thermal decontamination method for strawberries. PAW was produced by exposing potable water to dry air atmospheric plasma under various conditions (1 kVa, 10-40 min). Three PAW samples with different pH values (2.5, 2.75, and 3.0) were characterized by monitoring their pH, electrical conductivity, oxidation-reduction potential (ORP), and the concentrations of hydrogen peroxide, nitrite, and nitrate during 3 weeks of storage. The antimicrobial efficacy of PAW was evaluated against Escherichia coli ATCC 25922 and Botrytis cinerea in suspension. PAW with pH 2.5 exhibited the strongest antimicrobial activity, reducing E. coli and B. cinerea populations by up to 7 log CFU mL-1 and 5 log CFU mL-1, respectively, after 30 minutes of contact in suspension. The storage study demonstrated that PAW-treated strawberries maintained significantly lower microbial counts throughout 7 days of storage at 4 °C. On strawberry surfaces, a 15-minute treatment with PAW (pH 2.5) reduced E. coli and B. cinerea populations by 3.13 and 1.99 log CFU g-1, respectively. The total aerobic psychrophilic bacteria count in PAW-treated strawberries increased by only 0.8 log CFU g-1 during storage, compared to 1.4 log CFU g-1 in control samples. Importantly, PAW treatment did not adversely affect physical and chemical quality attributes of strawberries, including pH, ascorbic acid content, total antioxidant activity, anthocyanin content, and color parameters. These findings demonstrate that PAW is an effective, environmentally friendly alternative to conventional chemical sanitizers for reducing microbial contamination on strawberries while preserving their quality during refrigerated storage.This study investigated the potential of plasma-activated water (PAW) as a non-thermal decontamination method for strawberries. PAW was produced by exposing potable water to dry air atmospheric plasma under various conditions (1 kVa, 10-40 min). Three PAW samples with different pH values (2.5, 2.75, and 3.0) were characterized by monitoring their pH, electrical conductivity, oxidation-reduction potential (ORP), and the concentrations of hydrogen peroxide, nitrite, and nitrate during 3 weeks of storage. The antimicrobial efficacy of PAW was evaluated against Escherichia coli ATCC 25922 and Botrytis cinerea in suspension. PAW with pH 2.5 exhibited the strongest antimicrobial activity, reducing E. coli and B. cinerea populations by up to 7 log CFU mL-1 and 5 log CFU mL-1, respectively, after 30 minutes of contact in suspension. The storage study demonstrated that PAW-treated strawberries maintained significantly lower microbial counts throughout 7 days of storage at 4 °C. On strawberry surfaces, a 15-minute treatment with PAW (pH 2.5) reduced E. coli and B. cinerea populations by 3.13 and 1.99 log CFU g-1, respectively. The total aerobic psychrophilic bacteria count in PAW-treated strawberries increased by only 0.8 log CFU g-1 during storage, compared to 1.4 log CFU g-1 in control samples. Importantly, PAW treatment did not adversely affect physical and chemical quality attributes of strawberries, including pH, ascorbic acid content, total antioxidant activity, anthocyanin content, and color parameters. These findings demonstrate that PAW is an effective, environmentally friendly alternative to conventional chemical sanitizers for reducing microbial contamination on strawberries while preserving their quality during refrigerated storage.