Treatment of beef with gaseous ozone: Physicochemical aspects and antimicrobial effects on heterotrophic microflora and listeria monocytogenes

Abstract

The treatment of beef with gaseous ozone (GO) was analyzed and the physicochemical characteristics (texture, lipid oxidation, surface color) and food safety (microbial growth of heterotrophic microflora and inoculated Listeria monocytogenes) were evaluated. Transient changes in ozone concentration within the chamber were mathematically modeled using a non-stationary mass balance. Ozone pulses were applied and treatment intensities were evaluated in each case. GO treatment prolonged refrigerated storage of vacuum packed beef. Long periods of exposure to ozone (>10 min) negatively affected the red color and oxidative rancidity. The most effective treatments to control microbial flora were ozone pulses ranging between 5 and 10 min duration every 30 min for 5 h using 280 mg O3 m−3; these treatments allowed the reduction of more than 1 logarithmic cycle the counts of the natural flora in beef (lactic acid bacteria, mesophilic and enterobacteriaceae), maintaining oxidative stability and adequate physicochemical parameters. Additionally these low doses of GO decreased the counts of inoculated L. monocytogenes (102 CFU g tissue−1) to values below the detection limit for 16 days at 4 °C limiting its growth during refrigerated storage. The use of GO in beef products allows the control of microbial growth during refrigerated storage maintaining high quality parameters.