# Differential Proteomic Analysis of _Listeria monocytogenes_ during High-Pressure Processing
###### Abstract  
High-pressure processing (HPP) is a prevailing non-thermal food preservation technology. The inactivation mechanisms of _Listeria monocytogenes_ under sub-lethal to lethal damage by different levels of HPP treatments were conducted by label-free quantitative proteomic analysis. HPP might promote translation initiation due to population of most ribosomal subunits and initiation factors. However, protein synthesis was arrested according to the shortage of proteins responsible for elongation, termination and recycling. The quantitative proteomics approaches provide fundamental information on _L. monocytogenes_ under different HPP pressures, and provide theoretical support for HPP against Listeriosis illness and for promotion of safer ready-to-eat foods. HPP, 2022, 11, 1152, [[https://doi.org/10.3390/biology11081152](https://doi.org/10.3390/biology11081152)]([https://doi.org/10.3390/biology11081152](https://doi.org/10.3390/biology11081152))  
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Listeria monocytogenes.The U.S. Centers for Disease Control and Prevention estimate that approximately 1600 people become sick and 94% will be hospitalized yearly [1]. _L. monocytogenes_ can contaminate various food, including raw meat, seafood and vegetables, ready-to-eat (RTE) processed foods, and unpasteurized milk or milk products. The U.S. Department of Agriculture's Food Safety and Inspection Service (FSIS) established a zero-tolerance policy for _L. monocytogenes_ in RTE meat and poultry products [2]. In the European Union, 5175 cases of listeriosis, more than 2 fold the cases in 2018, and the highest case fatality rate (17.6%) among foodborne diseases were reported according to the 2019 zoonoses report. A significant increase in confirmed listeriosis cases in the European Union was also observed from 2009 to 2018 [3]. High-pressure processing (HPP) treatment is among the most established non-thermal pasteurization techniques for food preservation by inactivating vegetative putrefaction and pathogenic bacteria with minimal degradation of the nutritive and organoleptic quality of food [4; 5]. Application of HPP to food is mainly at a range of 100-800 MPa. The primary target of HPP is the denaturation of proteins and enzymes, the disruption of membrane and ribosomes, and the leakage of intracellular material when the pressure is higher than 400 MPa. HPP can eliminate _L. monocytogenes_ in several types of meat products and partially reduce nitrites without causing negative effects on the safety of RTE dry-fermented sausages [6]. HPP can extend the shelf life of rehydrated saltfish from 5 days to more than 49 days [7]. HPP can also inactivate microbial loads and retard total volatile basic nitrogen (TVB-N) production to better preserve Asian hard claims during refrigerated storage with pressures of 400-600 MPa for 3 min [8]. The mass spectrometry (MS)-based proteomics approach comprehensively enables the identification, quantification, and characterization of global proteomes and post-translational modifications [9]. The most substantial developments in sensitivity and quantification can be attributed to significant advances in nano-UPLC, fast-scanning high-resolution accurate MS, and bioinformatics analysis methods [10]. Gene set enrichment analysis of a barotolerant _L. monocytogenes_ strain S2542 indicated that HPP (400 MPa/5 min or 600 MPa/5 min) induced a significant reduction in the expression of the PrfA and SigB regulons [11]. PrfA is the primary virulence regulator, and SigB (\(\updelta\)), in concert with PrfA helps regulate virulence in _L. monocytogenes_.