Inactivation mechanisms of cold plasma on Bacillus cereus biofilms and its application in simulated meat processing...

Bacterial biofilms are a common source of contamination in the food industry, often forming on surfaces such as equipment and pipelines, and contributing to the spread of foodborne diseases. This study aims to evaluate the effectiveness of an atmospheric pressure plasma jet (APPJ) in inactivating Bacillus cereus biofilms on glass surfaces and to explore the underlying sterilization mechanisms. Meanwhile, the formation conditions of biofilms in the beef slaughtering and processing environments are simulated to assess the application potential of plasma technology in the food industry. Results showed that 240 s of APPJ treatment reduced biofilm levels by 3.77 Log CFU/glass and significantly degraded extracellular polysaccharides, disrupting the dense structure of the biofilm matrix. The treatment also caused oxidative damage to bacterial cells, leading to the release of proteins and DNA, while inducing oxidative stress that increased reactive oxygen species (ROS) and malondialdehyde (MDA) levels within the bacteria. Metabolomic analysis further revealed that APPJ inhibited bacterial energy production and DNA replication and repair, contributing to bacterial inactivation. The plasma treatment demonstrated strong bactericidal effects on biofilms formed during simulated beef slaughtering (5.92 Log CFU/glass) and processing (6.35 Log CFU/glass). In summary, this study provides new insights into the mechanisms by which plasma technology disrupts biofilms and offers a practical reference for controlling biofilm contamination in food processing environments.