SAFETY OF READY-TO-EAT WATERCRESS USING ENVIRONMENTALLY FRIENDLY SANITIZATION METHODS

Abstract

Chlorine-based washing systems have been widely used by the fresh-cut industry. However, there is much interest in developing safer and more environmentally friendly sanitization methods. Watercress was immersed in sodium hypochlorite (100 mg/L), hydrogen peroxide (167 mg/L) or citric acid (10 g/L) or exposed to ultraviolet C (UV-C) light (6 or 18 kJ/m2 by exposure for 3 or 7 min, respectively), and stored in modified atmosphere packaging at 5C and 95% relative humidity. The respiration rate, packaging gas composition, color, microbiological growth (psychrotrophic and mesophilic microorganisms, Enterobacteriaceae, mold and yeasts), antioxidant capability, polyphenol content and sensory quality were measured. The different treatments did not affect the respiration rate (average 22 mg CO2/kg·h) after 14 days. Psychrotrophic bacteria reached approximately 7 log10 cfu/g, regardless of the treatment, after 14 days. UV-C decreased mesophilic counts, while H2O2 reduced Enterobacteriaceae. UV-C exposure increased the antioxidant capability, which was maintained throughout the storage. None of the treatments affected the color parameters and sensory quality. All of the treatments analyzed, especially UV-C, may be useful for maintaining watercress quality.