Cold atmospheric pressure plasma decontamination of allspice berries and effect on qualitative characteristics

The effect of low-temperature plasma generated at atmospheric pressure was studied in term of reduction of bacterial contamination and influence on nutritional characteristics of allspice (Pimenta dioica). The low-temperature plasma was generated in ambient air using Diffuse Coplanar Surface Barrier Discharge (DCSBD). The bacterial species inoculated on the surface of samples were reduced in dependence on exposure time. Plasma treatment time of 240 s led to log(10)CFU/g ofSalmonellaEnteritidis to below detection level (1.0 log(10)CFU/g) from initial population of 7.64 log(10)CFU/g. After treatment with DCSBD plasma for 300 s, the populations ofBacillus subtilisandBacillus subtilisendospores were decreased by 2.85 log(10)CFU/g and 1.70 log(10)CFU/g, respectively. The parameters related to the decontamination effect were measured. Temperature of samples does not exceed the value declared as low-temperature limit and water activity decreased after plasma treatment. The effect of plasma on the qualitative properties of allspice studied by infrared spectroscopy showed no changes in characteristic chemical bonds on the surface and also inside the samples. Measurements of polyphenolics content in allspice showed that plasma has negligible impact on these main constituents affecting taste and flavor. The experiments demonstrated an efficient reduction in microbial contamination and minimal influence on the aroma profile of treated and stored spice.