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A novel strategy involving Olive Leaf Extract (OLE) and Cold Atmospheric Plasma (CAP) was developed as a green antimicrobial treatment. Specifically, we reported a preliminary investigation on the combined use of OLE + CAP against three pathogens, chosen to represent medical and food industries (i.e., <i>E. coli</i>, <i>S. aureus</i> and <i>L. innocua</i>). The results indicated that a concentration of 100 mg/mL (total polyphenols) in OLE can exert an antimicrobial activity, but still insufficient for a total bacterial inactivation. By using plain OLE, we significantly reduced the growth of Gram positive <i>S. aureus</i> and <i>L. innocua</i>, but not Gram-negative <i>E. coli</i>. Instead, we demonstrated a remarkable decontamination effect of OLE + CAP in <i>E. coli</i>, <i>S. aureus</i> and <i>L. innocua</i> samples after 6 h. This effect was optimally maintained up to 24 h in <i>S. aureus</i> strain. <i>E. coli</i> and <i>L. innocua</i> grew again in 24 h. In the latter strain, OLE alone was most effective to significantly reduce bacterial growth. By further adjusting the parameters of OLE + CAP technology, e.g., OLE amount and CAP exposure, it could be possible to prolong the initial powerful decontamination over a longer time. Since OLE derives from a bio-waste and CAP is a non-thermal technology based on ionized air, we propose OLE + CAP as a potential green platform for bacterial decontamination. As a combination, OLE and CAP can lead to better antimicrobial activity than individually and may replace or complement conventional thermal procedures in food and biomedical industries.