This study investigated the effects of isochoric freezing (IF) on the shelf-life and quality of raw bovine milk over a 5-week period. The results were compared with conventional refrigeration (RF) and refrigeration after pasteurization (HTST). The IF treatment process entailed storing liquid raw milk in isochoric chambers in thermodynamic equilibrium at −5 °C/77 MPa and −10 °C/96 MPa. Several parameters were analyzed, including microbiology count, physicochemical properties, indigenous enzyme activity, protein content, volatile organic compounds profile, and lipid degradation. Both raw and pasteurized milk experienced increases in the microbial level past the acceptable threshold (≥5.5 log CFU/mL) after 2 weeks and 5 weeks, respectively, leading to the deterioration of other parameters during storage. In comparison, microbiology count decreased significantly during storage for both IF treatment conditions but was more pronounced for the higher pressure (96 MPa) treatment, leading to undetectable levels of microorganism after 5 weeks. IF treatment maintained stable pH, titratable acidity, viscosity, lipid oxidation, volatile profiles, total protein content, and lactoperoxidase activity throughout the storage period. Color was preserved during IF treatment at −5 °C/77 MPa; however, color was impacted during IF treatment at −10 °C/96 MPa. Protein structures were also modified during pressurized storage in both IF treatments. Overall, the study demonstrated that isochoric freezing could significantly increase the shelf-life of milk by reducing microbiology activity, whilst maintaining its nutritional content. These results underscore the potential role of isochoric freezing as a valuable tool in eliminating pathogens while maintaining quality characteristics similar to raw milk over long storage periods.

In this study, we investigate the potential of low-pressure isochoric freezing (LPIF) at −1.5 °C/15 MPa to simultaneously inhibit microbial growth and preserve fresh-like physiochemical and bioactive properties during storage. Using raw cow’s milk as a model product, we compared LPIF conditions to conventional refrigeration (4 °C) and atmospheric-pressure supercooling (−1.5 °C) over a 5-week storage period. Low-pressure isochoric freezing conditions effectively inhibited the growth of aerobic mesophiles and key microbial spoilage agents (Pseudomonas spp.), whereas significant growth was observed under both un-pressurized conditions. Low-pressure isochoric freezing furthermore showed reduced milk degradation across quality parameters, including pH, titratable acidity, colour, and volatile organic compounds profile. These data demonstrate that the synergistic effects of mild low temperatures and mild enhanced pressures encountered during LPIF can significantly improve preservation for storage periods up to 5 weeks, relative to paired controls leveraging low temperature alone. Given the passive nature of the technique and the compatibility of the employed pressures with standard industrial compressed gas containers, these results suggest a route towards a scalable new cold storage modality.