The persistence of contamination in food processing lines and contact surfaces has caused rapid economic losses for the food industry and increased health risks. Pseudomonas spp. is extensively reported as a spoilage microorganism in food stores under aerobic conditions (Bassey et al., 2021; Comi, 2017) and frequently detected in foods such as vegetables, fruits, milk, meat, and water, including various food processing surfaces (Liu et al., 2021). It effectively competes with other microorganisms for resources due to physiological strategies that allow curtailing the growth of its competitors (Nolan & Allsopp, 2022). It also poses a significant risk of severe chronic and acute infections such as otitis, soft tissue attack, urinary tract infections, and respiratory infections, particularly in immunocompromised individuals (Fernández-Billón, Llambías-Cabot, Jordana-Lluch, Oliver, & Macià, 2023). High P. aeruginosa counts in water distribution systems have also posed a serious food safety threat in China (Liu et al., 2022).

The uncomplicated cellular arrangement and plasticity of bacteria at the gene level enable them to activate specific response mechanisms for essential genetic and cellular adaptation under adverse conditions (Shome, Talukdar, Nath, & Tewari, 2023). These include i) producing thick biofilms, ii) reducing the affinity of the antibacterial compounds for the bacterial target, iii) decreasing the entry of antibiotics via the bacterial cell membrane, and iv) accumulating defense compounds for releasing quorum sensing (QS) inducers (necessary for biofilm formation) from the cell (Shome, Talukdar, & Upadhyaya, 2022). In P. aeruginosa, QS is triggered by a complex network of receptors and response regulators. QS comprises three primary circuits (las, rhl, and pqs), arranged in a series for the expression of virulence factors (Kostylev et al., 2019). When the concentration of N-acyl homoserine lactone (AHL) signaling molecules reaches a threshold level, target genes are activated, which facilitates the production of virulence factors and pathogenesis-promoting enzymes, such as exotin, elastase, protease, pyocyanin, and siderophores (Schuster & Peter Greenberg, 2006). Overall, the micro-actions of individual cells in a biofilm determine the macro-action of the overall biofilm, allowing it to produce matrix components, surfactants, and detoxifying proteins for structural stability, migration, and defense against external threats (Penesyan, Paulsen, Kjelleberg, & Gillings, 2021) Since the function of these QS pathways are essential in biofilm formation as demonstrated by genetic analysis of biofilms, it is imperative to explore innovative and green measures to effectively inactivate P. aeruginosa.

High-power pulsed microwave (HPPM), an innovative nonthermal technology, has shown remarkable advantages over other technologies. It can generate frequency waves similar to electromagnetic waves, with frequencies ranging from 300 MHz to 300 GHz, significantly higher than those of home (2.45 GHz) and industrial microwaves (915 MHz or 2.45 GHz) (Guo, Sun, Cheng, & Han, 2017). Although HPPM has been extensively applied in the medical field to investigate the impacts of repeated exposure on cancer incidence and biological effects (de Seze et al., 2020), it has gained traction in food science due to its simple handling after decontamination and the ability to maintain the structural and nutrient compositions of foods. HPPM can directly interact with specific (polar) molecules, aiding an array of bioeffects, including the modification of intracellular oxidative defense machinery and DNA damage-induced inactivation of bacterial cells (Shaw et al., 2021). However, the inactivation mechanism of HPPM against biofilm-forming P. aeruginosa has not been explored.

Proteomics has been explored to unravel protein responses, helping to describe microbial metabolism and elucidate protein-mediated biological responses to diverse experimental factors (Bassey, Ye, Li, & Zhou, 2021). Thus, tandem mass tags (TMT)-based quantitative proteomics was explored to investigate the inactivation efficacy and the underlying mechanisms of HPPM treatment against P. aeruginosa. The result will deepen the molecular insights of HPPM treatment against P. aeruginosa and provide a reference for controlling other pathogenic microorganisms of food safety concern.