Individual and combined effects of ultrasound, ozone and chlorine dioxide on strawberry storage life

- Combinations of ultrasound with ozone and chlorine dioxide were the most effective treatment.
- Among the individual treatments, better results were achieved using chlorine dioxide.
- All treatments reduced the physiological deterioration and spoilage of strawberry.

The objectives of this study were to determine the effectiveness of ultrasound and the chemical sanitizers ozone and chlorine dioxide, alone and in combination, on strawberry storage life. Fruits were treated with 0.075 mg/L ozone, 6 mg/L chlorine dioxide and ultrasound at 30 Watt, combination of ultrasound plus ozone and combination of ultrasound plus chlorine dioxide for 5 min and stored for up to 4 weeks at 4 °C. All treatments inhibited mold growth during storage. However, individual ozone treatment causes bleaching of the fruit. Ultrasound treatments with ozone and chlorine dioxide were more beneficial for quality factors such as pH, total soluble solids, electrical conductivity and texture compared with the individual treatment or untreated fruit. Also, nondestructive near infrared spectroscopy in transmission and reflectance modes gave promising results for evaluating the sugar and water content of the fruit. Overall our findings suggest that combinations of ultrasound plus ozone and chlorine dioxide could be used for prolonging shelf life of strawberries.