Afterglow corona discharge air plasma (ACDAP) for inactivation of common food-borne pathogens

- Afterglow corona discharge air plasma (ACDAP) was generated with a DC voltage of 20 kV and a frequency of 58 kHz.
- As high as 3.5-log reduction in viability of tested food pathogens was observed.
- Inactivation pattern was better explained by using pseudo-first-order kinetics.
- Temperature and humidity fluctuations are within the normal range by plasma exposure.

Atmospheric pressure cold plasma technology is becoming increasingly popular for microbiological decontamination of food and bio-materials. In the present study, afterglow corona discharge air plasma (ACDAP) was used for the inactivation of most common food-borne pathogens, namely pathogenic Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Bacillus cereus, Listeria monocytogenes, and Vibrio parahaemolyticus. Corona discharge plasma was generated at an output voltage of 20 kV DC, and a frequency of 58 kHz. And, a centrifugal blower that provides an airflow velocity of 2.5 m/s at electrode tip level was used for generating the flowing afterglow of the plasma. During plasma exposure, about 20 °C rise in temperature and a 50% decrease in relative humidity were observed in a treatment chamber within 3 h of exposure. Upon ACDAP exposure, as high as 3.5-log (99.97%) reduction in viable cell counts of tested food pathogens, especially E. coli O157:H7, was observed over a 24-hour exposure. The pathogen inactivation pattern was better explained by using the Singh-Heldman model, which belongs to pseudo-first-order kinetics. In conclusion, ACDAP was shown to be effective for the inactivation of common food-borne pathogens.