From Waste to Natural Preservation: An Experimental Study on Using Olive Oil Mill Wastewater Phenolic Compounds for Surimi Safety and Shelf-life Extension

This study investigates the application of phenolic compounds extracted from Olive Mill Wastewater (OMW) as a natural preservative to extend the shelf life and enhance the quality of Red Mullet (Mullus barbatus) surimi. Given the vulnerability of fish and the dual antioxidant-antimicrobial properties of phenolic compounds, this research aims to evaluate the valorization of these compounds to mitigate microbial spoilage and lipid oxidation. Beyond improving food safety, quality, and organoleptic characterization, this research contributes to environmental protection through waste valorization and the circular economy. The phenolic extract, derived via enzymatic hydrolysis and a multi-stage membrane system, was spray-dried and incorporated into surimi during mincing. The experimental design compared two processing protocols: washing before freezing versus washing after thawing, to evaluate their impact on product stability. Samples were stuffed into collagen casings, steam-cooked, and stored under modified-atmosphere packaging (80% N2 /20% CO2) at 4 ± 1°C for up to 60 days, with analyses at 0, 15, 30, 45, and 60 days. To determine shelf life and quality, microbial growth (TVC, LAB, specifically Lactobacillus spp., Staphylococcus aureus, yeasts, and molds) and physicochemical properties (pH, aw, TVB-N, peroxide value, acidity, and conjugated dienes) were monitored. Preliminary results suggest that the phenolic extracts, combined with an optimized protocol and controlled packaging, maintain microbial counts below spoilage thresholds. This research offers a sustainable strategy for improving food safety and quality, particularly for seafood products, while reducing environmental impact and the reliance on synthetic additives.