## 5 Conclusions  
Our study demonstrated that HPP improves the microbial and chemical quality of high-oil-content pesto sauce compared with thermal processing. The HPP significantly reduces _Listeria monocytogenes_ and _Salmonella_ Typhimurium counts (more than 4-log reduction) without being significantly affected by the oil content. Furthermore, the lipids are well preserved by HPP, as shown by low peroxide and p-anisidine values (under 10 meq/Kg oil). This activity increases the total phenolic content, indicating higher antioxidant properties than those observed before the treatment. The presence of functional compounds, particularly phenolics, including terpen with antimicrobial properties found in basil, likely contributes to the prolonged shelf life and maintains the quality of the pesto sauce. These ingredients--in addition to enhancing the nutritional profile, taste, and texture of the food--help boost the efficacy of this non-thermal preservation tool for high-oil-content foods, further solidifying HPP as an effective method for controlling spoilage organisms.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app14209425/s1](https://www.mdpi.com/article/10.3390/app14209425/s1)]([https://www.mdpi.com/article/10.3390/app14209425/s1](https://www.mdpi.com/article/10.3390/app14209425/s1)), Figure S1: Gallic Acid Standard Curve; Table S1. Preparation of gallic acid standards for calibration curve.  
Conceptualization, J.K., E.S. and K.R.; methodology, E.S., K.R., J.K. and S.P.; validation, E.S., K.R. and J.K.; formal analysis, E.S.; investigation, E.S., K.R., S.P., L.I.C., K.P.T. and H.H.: writing--original draft preparation, E.S., K.R., S.P., L.I.C. and K.P.T.: writing--review and editing, J.K. and M.H.; supervision, J.K. and M.H. All authors have read and agreed to the published version of the manuscript.  
This research was partly funded by the European Union, with the European Regional Development Fund A80382, admitted by the Regional Council of Pohjois-Savo.  
Not applicable.  
The raw data supporting the conclusions of this article will be made available by the authors on request.  
We want to acknowledge the European Regional Development Fund and the Regional Council of Pohjois-Savo, via which the regional ELTUVA project (A80382, 2023-2025) has enhanced research and innovation capacities and the uptake of advanced technologies for developing high-quality and safe food. We want to thank Company Ca-Sa Valimeren Herkut Oy, especially [PERSON] and [PERSON], for preparing and supplying the pesto sauce and being supportive of this study, as well as Toripiba Oy for HPP processing. We thank SIS Labs at Department of Technical Physics in the University of Eastern Finland for providing GC-MS facilities. We are also thankful for [PERSON] and [PERSON] from Development Company SavGrow Ltd. for kind cooperation in the ELTUVA project supporting this study. Moreover, we wish to thank our skillful laboratory personnel, [PERSON] and [PERSON], for their assistance in maintaining and developing the laboratory methodology.  
The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results. The companies CA-SA Valimeren Herkut and Tori-piha Oy were participating in the ELTUVA project but had no role in the design of the study, analyses, interpretation of data, or writing of the manuscript.