A protocol for the use of cold plasma treatment to inhibit in vitro growth of Fusarium graminearum.

Cold plasma is an ionised gas that can be used to control a range of microorganisms. In this study, a protocol was developed for cold plasma treatment of in vitro growth of Fusarium graminearum, a global mycotoxic species generally associated with cereal grain. Four F. graminearum isolates on potato dextrose agar (PDA) were treated with cold plasma for 70 s from a distance of 21 cm in a closed environment, and their radial colony growth was measured. To consider whether cold plasma modified the culture media, non-inoculated half-strength PDA plates were also treated with cold plasma prior to inoculation with the F. graminearum isolates. Similarly, to determine if a rise in temperature during the treatment impacted the growth of the isolates or the culture media itself, the plates were treated with dry heat before and after inoculation with the isolates. Treatment of F. graminearum isolates with cold plasma inhibited their growth and was not associated with the culture media or the rise in temperature during the treatment. Optical emission spectroscopy of cold plasma identified reactive (ionised) species of argon, nitrogen, hydrogen, oxygen, copper, and carbon with the highest number of peaks produced for argon. These results demonstrate that cold plasma can significantly reduce the in vitro growth of F. graminearum isolates when treated in a closed environment and suggest there is potential to control the in vivo growth of F. graminearum.