Modelling microbiological and quality marker responses to enhance cold plasma cereal grain processing

This study employed response surface modelling to establish key process parameters for high voltage dielectric barrier discharge (HVDBD) atmospheric cold plasma (ACP) decontamination of cereal grains that were in alignment with maintenance of product critical quality parameters. Response surface modelling of experimental data probed the key factors in relation to microbial control and seed germination promotion. Depending on treatment parameters and target intrinsic characteristics, significant reduction of microbial contamination on wheat and barley grains was achieved. The efficacy of the plasma treatment (20 min) against microorganisms decreased in the following order: E. coli > P. verrucosum (spores) > B. atrophaeus (vegetative cells) > B. atrophaeus (endospores). Germination percentage of samples treated for up to 5 min was not affected, but it was decreased after 20 min of treatment. Overall, ACP was effective for cereal grain decontamination, however the diverse native micro-flora may pose greater resistance to the closed surface decontamination approach than the individual fungal or bacterial challenges.