Inactivation of foodborne pathogens on the surfaces of different packaging materials using low-pressure air plasma

- Low-pressure air plasma was generated over a wide range of pressures.
- Usefulness of the plasma for sterilization of food packaging materials was tested.
- A 4-log reduction in pathogens' viability was observed within 5 min of exposure.
- Modeling of microbial survival during plasma exposure.
- Materials' optical and mechanical properties were unaffected by plasma exposure.

In the present study, low-pressure glow discharge plasma was used for surface decontamination of the common food packaging materials, namely glass, polyethylene, polypropylene, nylon, and paper foil. Low-pressure air plasma was generated over a vacuum pressure range of 0.5-5.0 Torr, and at a power density range of 12.4-54.1 mW/cm3. Compared to plasma-unexposed surfaces, no significant changes in optical properties, color characteristics, surface temperatures, tensile strengths, and deformation strains were observed with plasma-exposed surfaces. On plasma exposure of food pathogens-loaded packaging materials surfaces, as high as 4-log reduction (99.99%) in viable cell counts of tested food pathogens, especially Escherichia coli O157:H7 and Staphylococcus aureus, was observed within 5 min. And, the pathogens inactivation pattern can be better explained by Singh-Heldman model. Therefore, low-pressure air plasma was shown to be effective for inactivation of major foodborne pathogens, and different food packaging materials can be decontaminated using the plasma without adversely affecting their physical properties.