SUPERCRITICAL CARBON DIOXIDE DRYING PROCESS OF SHRIMP: EVALUATION OF ITS EFFECTIVENESS USING STORAGE TEST AND CHALLENGE TEST

Supercritical carbon dioxide (scCO₂) is an emerging and sustainable technology for food processing, capable of combining drying and microbial inactivation at low temperatures. This study evaluated the effectiveness of scCO₂ treatment applied to shrimp (Parapenaeopsis stylifera), a highly perishable seafood product prone to microbial contamination during storage and distribution. The primary objective was to assess the microbiological safety of scCO₂-dried shrimp through challenge tests, aimed at verifying the inactivation of pathogenic and spoilage microorganisms, and storage tests, designed to monitor microbial stability over time. The results were compared with samples processed using conventional hot-air drying and freeze-drying, two widely used technologies in the food industry. Challenge tests were conducted in accordance with ISO 20976-2:2022, using surrogate strains of pathogenic microorganisms to evaluate the inactivation potential of the treatment. The results confirmed the absence of detectable pathogens in treated samples, demonstrating a strong inactivation capacity. In addition to pathogen-focused testing, the study examined the natural microbiota of shrimp before and after treatment, comparing scCO₂ drying with conventional hot-air drying and freeze-drying. Microorganisms commonly associated with spoilage and foodborne illness (including mesophilic bacteria, Pseudomonas spp., molds, yeasts, E. coli, enterobacteria, and mesophilic lactic acid bacteria) were monitored across all treatments. To assess long-term microbial stability, storage tests were performed at six distinct time points: 0, 15, 30, 60, 90, and 120 days, with samples stored under vacuum at 20 °C in the absence of light. Throughout the entire storage period, scCO₂-treated samples consistently exhibited lower microbial loads compared to those processed with conventional methods, often remaining below the detection threshold. Experimental data demonstrated that scCO₂ treatment effectively inactivates microbial populations and ensures long-term microbiological stability, significantly reducing the risk of bacterial growth during shelf life. These findings highlight the potential of scCO₂ as a viable alternative to traditional methods, offering clear advantages in terms of food safety and process sustainability.