Low-pressure isochoric freezing as a scalable technique for fresh food preservation

Abstract 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.