Cold atmospheric plasma (CAP) is a non-thermal decontamination technology capable ofgenerating groups of antimicrobial agents including; photons, electrons, positively andnegatively charged ions, atoms, free radicals and excited or non-excited molecules. CAPtreatments (70 kV, 50 Hz) at different times (i.e. 15, 30, 60, 90 s) were applied to a broth sys-tem inoculated either with Escherichia coli NCTC 12900, E. coli ME 9062 or E. coli knockoutmutants of soxS, rpoS and dnaK genes. Optical emission spectra were performed and themain antimicrobial reactive substances generated by CAP treatments were found to be N2,N2+, NO, H�and He. After treatments, reduction levels of the studied bacteria were up to0.5 log CFU/mL, no showing statistical differences. Moreover, the kinetic growth parameterswere calculated by applying the 2-fold dilution method. �maxdecreased in all bacteria whenthe time of CAP treatment increased. E. coli dnaK was the most sensitive mutant to plasma,showing no recovery after CAP of 60 and 90 s. In addition, CAP challenge test treatmentswere applied on butter head lettuce inoculated with E. coli NCTC 12900 with CAP treatmentsof 60 and 90 s reducing bacteria levels by more than 1.5 log CFU/cm2.