Development of innovative and sustainable food process for pasteurization through a holistic analysis

This thesis addresses food safety with a specific focus on pasteurization strategies based on supercritical carbon dioxide (SC-CO2). The aim was to evaluate this non-thermal technology as an alternative to conventional treatments, preserving product quality while ensuring microbiological safety. Three different SC-CO2 processes were studied, including one innovative configuration that led to a patent application. In addition, the combination of SC-CO2 with natural antimicrobial compounds such as essential oils and terpenes was investigated. Results showed that SC-CO2 was able to achieve microbial reductions of up to ~3 log at temperatures between 30 and 45 °C, with higher efficacy in the SC-CO2MAP+ process. The integration with natural antimicrobials further enhanced inactivation in specific systems, confirming the potential of hurdle technology. In parallel, the growth behavior of Listeria monocytogenes at 7 °C was investigated under different modified atmosphere packaging (MAP) conditions and pH levels, using both liquid media (broths) and solid matrices (agar). Growth was not completely inhibited, but high-CO2 atmospheres combined with lower pH significantly slowed down the development of the microorganism. This finding is particularly relevant in the context of sustainable packaging materials, which often present reduced gas barrier properties and may compromise MAP effectiveness. Overall, this work demonstrates the potential of SC-CO2, alone or in combination with natural antimicrobials, as an innovative technology for microbial inactivation, and provides new insights into the role of packaging conditions in the control of Listeria monocytogenes. The results are especially relevant for ready-to-eat foods, in light of the recent European regulatory framework that introduced stricter limits for Listeria in foods that support its growth (Regulation (EU) 2024/2895). This research provides a scientific basis for future industrial applications, combining microbial safety with sustainability in line with the goals of the 2030 Agenda.