Assessment of the efficacy of a low-temperature gas plasma prototype for superficial decontamination of table eggs

A resistive barrier discharge (RBD) prototype was set-up in order to decontaminate table eggs surface from Salmonella Enteritidis and Listeria monocytogenes. The eggs were treated in the discharge afterglow where the gas temperature was similar to room temperature, thus minimizing thus the risk of thermal alterations of the samples. The examined prototype appeared to be very effective for the inactivation of both the pathogens deliberately inoculated onto the surface of egg shells. Its efficacy was significantly increased when treatments were performed in the presence of humid air: in particular, reductions ranging between 4 and 5 Log CFU/egg shell in relation to the time of treatment were achieved for both the pathogens with the highest relative humidity in the treatment chamber. Moreover, a gas plasma treatment of 90 minutes only slightly affected the egg cuticle without other modifications of the egg.