MH-agar plate surfaces inoculated with E. coli and S. aureus and Tryptone Soya Agar (TSA, CM 0131, Oxoid Ltd., Thermo Fisher Scientific, Basingstoke, Hampshire, UK) with L. monocytogenes were prepared as described in Section 3.7. A volume of 10 µL of each pure EO was added to sterile filter discs with a diameter of 6 mm, and sterile water was used as control. The discs were placed on the inside center of a Petri dish lid in a sterile working hood. A control was also prepared by adding 10 µL of sterile water to the filter discs.