In-package atmospheric pressure cold plasma treatment of strawberries

• In-package cold plasma treatment of strawberries based on dielectric barrier plasma discharge.
• Electrical characterisation of the plasma discharge revealed a filamentary regime and ozone production.
• A significant background microflora reduction was achieved.
• No adverse changes in respiration rates, texture and colour of treated strawberries.

The ability to generate low temperature plasma at atmospheric pressure offers new opportunities to decontaminate biological materials, including fresh foods. In this study, strawberries were treated with atmospheric cold plasma (ACP), generated with a 60 kV dielectric barrier discharge (DBD) pulsed at 50 Hz, across a 40 mm electrode gap, generated inside a sealed package containing ambient air (42% relative humidity). The current–voltage characteristics revealed that the plasma operated in the filamentary regime. The background microflora (aerobic mesophillic bacteria, yeast and mould) of strawberries treated for 5 min was reduced by 2 log10 within 24 h of post-ACP treatment. The respiration rate of ACP treated produce, measured by the closed system approach, showed no significant increase. The effect of ACP on strawberry colour and firmness was insignificant.