Controlling Brochothrix Thermosphacta as a Spoilage Risk Using in Package Atmospheric Cold Plasma

Brochothrix thermosphacta is a predominant spoilage microorganism in meat and its control in processing environments is important to maintain meat product quality. Atmospheric cold plasma is of interest for control of pathogenic and spoilage microorganisms in foods. This study ascertained the potential of dielectric barrier discharge atmospheric cold plasma (DBD-ACP) for control of B. thermosphacta in response to key parameters such as treatment time, voltage level, interactions with media composition and post treatment storage conditions. Challenge populations were evaluated as suspensions in PBS, as biofilms in meat model medium and surface attached on raw lamb chops under MAP. ACP treatment (80kV) for 30s inactivated B. thermosphacta populations below detection in PBS, while 5 min treatment achieved a 2 Log cycle reduction using a complex meat model medium and attached cells, suggesting useful control for meat processing facilities. A ‘worst case scenario challenge’ of high population density on a nutritious medium in a biofilm matrix was evaluated using a surface inoculated lamb chop and the antimicrobial efficacy of plasma was reduced but still apparent over the 10 day storage period. However, there is scope to further enhance microbial control leading to meat storage life extension through adjusting the modality of treatmen