The effect of cold plasma technique on some pathogen microorganisms for meat products

In this research, the effect of cold plasma on Listeria monocytogenes and Staphylococcus aureus inoculated on sliced pastirma was investigated. In the study, cold plasma which was produced using oxygen gas for 3 min (SP1), oxygen gas for 5 min (SP2), argon gas for 3 min (SP3), argon gas for 5 min (SP4), % 50-50 argon-oxygen gas for 3 min (SP5), % 50-50 argon-oxygen gas for 5 min (SP6), % 75-25 argon-oxygen gas for 3 min (SP7) and % 75-25 argon-oxygen gas for 5 min (SP8), was applied to pastirmas. While moisture contents of samples which was applied cold plasma process were between 44,54-51,88 %, there were not any significant changes in pH values. Both moisture content and water activity values of pastirma samples decreased by the application of cold plasma process. The maximum decrease in aw value was observed for SP7 and SP8 samples. SP1 sample which was treated with pure oxygen had 0,99 malonaldehyde/kg and it was the highest TBA value after cold plasma treatment compared to the TBA values of other samples. There has been significant changes in color values L*, a*, b* of pastirma samples. While the lightness of pastirmas decreased, the redness (a*) and the yellowness (b*) of the samples increased. As a result of cold plasma process applied to pastirma samples inoculated with Staphylococcus aureus and Listeria monocytogenes, maximum 0,95 log cfu/cm2 and 0,91 log cfu/cm2 decreases were observed for S. aureus and L. monocytogenes, respectively. Moreover cold plasma process decreased TMAB numbers, yeast-mold numbers and psychrophile bacterium numbers in pastirma samples up to 1,41, 1,66 and 1,58 log cfu/cm2, respectively. In this study, it was determined that cold plasma was effective on sensory properties. Color, appearance, flavor-aroma, texture and general discrimination points showed decrease compared to Control samples. This study showed that gas type and process period being used in cold plasma process was effective in inactivation of pathogens.