Inactivation of Staphylococcus aureus on the beef jerky by radio-frequency atmospheric pressure plasma discharge treatment

• Radio frequency atmospheric pressure plasma can inactivate Staphylococcus aureus.
• The plasma can severely damage the cell morphology of S. aureus.
• The plasma does not affect the fatty acid composition, color, and shear force of beef jerky.

Radio-frequency atmospheric pressure plasma discharge as an inactivation technique was tested to reduce Staphylococcus aureus on the surface of polystyrene, agar, and beef jerky. S. aureus ATCC12600 was reduced by 3–4 log colony forming unit on the polystyrene and agar after 2 min treatment, but on beef jerky sample after 10 min treatment. It suggests that the surface feature can significantly affect the inactivation of S. aureus by plasma. The scanning electron microscopy analysis showed that the S. aureus cells were disintegrated into pieces and many holes were created. The analysis of optical emission spectrum suggests that reactive oxygen species, especially the singlet state of oxygen at 777 nm are mainly responsible for the inactivation and cellular deformation of S. aureus. No significant change was found in the fatty acid composition, color and shear force of the beef jerky samples (p > 0.05). This study shows that radio-frequency atmospheric pressure plasma is effective in inactivation of S. aureus on the food samples such as beef jerky with little changes in nutritional and sensory qualities.Industrial relevanceInactivation of S. aureus on polystyrene, agar, and beef jerky samples using radiofrequency atmospheric pressure plasma is presented. The plasma treatment was a useful technology to reduce a microbial contamination on the surface of thin and dehydrated food products such as beef jerky. It is promising in the industrial application since no significant change was found in the fatty acid composition, color, and shear force of the beef jerky after the plasma treatment.