The effects of atmospheric cold plasma on inactivation of Listeria monocytogenes and Staphylococcus aureus and some quality characteristics of pastirma-A dry-cured beef product

In this study the effectiveness of cold atmospheric plasma (CAP) in inactivating two bacterial pathogens on inoculated pastirma was investigated. In addition, the effect of this treatment on the total mesophilic aerobic bacteria (TMAB) and yeast-mold counts was also observed. Pastirma samples were inoculated with Staphylococcus aureus and Listeria monocytogenes and subjected to CAP applications using oxygen (100%), argon (100%) and two oxygen/argon mixtures (25%O-2/75%Ar and 50%O-2/50%Ar) for 180 and 300s. Maximum reduction of 0.85 log CFU/cm(2) for S. aureus counts and 0.83 log CFU/cm(2) for L. monocytogenes counts were found from starting level of 5.78 and 5.71 log CFU/cm(2), respectively. However, it was determined that the TMAB and yeast-mold counts were reduced by 1.41 log CFU/cm(2) and 1.66 log CFU/cm(2), respectively. It was found that pastirma samples had a 7.34% decrease in moisture content as a result of CAP application due to evaporated water from the sample's surface. In the light of these results, this study showed that cold atmospheric plasma can be used to lower levels of S. aureus and L. monocytogenes in pastirma. Industrial relevance: Thermal treatments can cause sensory and nutrient changes in meat products. Non-thermal food processing technologies are innovative applications that continue to attract attention. Cold plasma, which is one of the non-thermal technologies, is environmentally friendly and causes minimal changes to treated products. In this study, cold atmospheric plasma treatment was effective against S. aureus and L. monocytogenes inoculated on pastirma and reduced their counts. Moreover, it also succeeded in reducing counts of TMAB and yeast-mold in the pastirma.