Label free-based proteomic analysis of proteins in Bacillus cereus spores regulated by high pressure processing and slightly acidic electrolyzed water treatment

To investigate the mechanism of high pressure processing (HPP, 200 MPa/20 min + 500 MPa/20 min) and slightly acidic electrolyzed water (SAEW, 44 mg/L available chlorine concentration (ACC)) on B. cereus spore inactivation, a label-free quantitative proteomics approach based on high-resolution mass spectrometry (MS) data was used. Quantification of 2810 proteins was obtained with high confidence. A total of 93 and 83 proteins showed significant differential abundance after HPP-SAEW and HPP treatments, respectively, and 21 proteins changed significantly when both treatments were compared. The results indicated that the spore cortex-lytic enzyme was upregulated 3.15 fold after HPP treatment, and the germination was influenced by ATP generation. The metabolic, degradation, signaling, and biosynthesis pathways were involved in HPP-SAEW mediated spore inactivation. Amino acid-biosynthetic and quorum sensing were the main KEGG pathways mediated by SAEW under HPP conditions. Specifically, our results showed that the phosphorylation of the Spo0A transcription factor was mediated by the downregulation of the ABC transporter ATP-binding protein, which was associated with inactivation of spores.