Effect of low-pressure cold plasma on surface microflora of meat and quality attributes

The aim of this study was to investigate the effect of cold plasma treatment on the inactivation of microorganisms on meat surface and its influence on colour of meat and pH value. Nitrogen, argon and helium plasma were generated by high voltage discharge in a vacuum chamber (final 0.8 MPa) with exposure times of 5 and 10 min. Total number of microorganisms, psychrotrophs and number of yeast and mould were determined using plate method. Instrumental evaluation of colour parameters L* a* b* was performed by colorimeter Minolta Cr 400. Psychrotroph bacteria counts and total number of microorganisms exposed to helium and argon plasma for 10 min were reduced about 3 log cfu/cm(2) and 2 log cfu/cm(2), respectively. Increasing reductions of yeasts and moulds were also obtained and were about 3 cfu/cm(2) (helium) and 2,6 cfu/cm(2) (argon). The usage of nitrogen plasma has not resulted in any significant reduction of counts of psychrotrophs and total. number of microorganisms. Yeasts and moulds were little affected by nitrogen plasma and their numbers decrease about 1 log cfu/cm(2.) after 10 min of treatment. No significant differences in colour parameters and pH value after cold plasma treatment were observed. These results demonstrated that cold plasma has antimicrobial activity and could be a promising method of biodecontamination, but further investigations focusing on meat quality have to be determinate.