Quality and Safety Assessment During the Ozonation of Cloudy Apple Juice

Traditionally, ozone processing within the food industry has focused on solid foods by either gaseous treatment or washing with ozonated water. However, with the FDA’s approval of ozone as a direct additive to food, the potential for liquid applications has emerged. This study investigates the effect of ozone processing on microbial inactivation (E. coli ATCC 25922 and NCTC 12900), and quality parameters (colour, phenolic content) of apple juice. Apple juice samples were ozonated at room temperature (20±1.5oC) with an ozone concentration of 0.048 mg O3 min-1 ml-1 and treatment time of 0 to 10 min at a constant flow rate of 0.12 L min-1. E. coli inactivation in apple juice was fitted using the Weibull and shoulder log-linear model. Ozone treatment of E. coli ATCC 25922 in apple juice resulted in complete inactivation within of 5 min treatment. Apple juice colour (L*, a* and b*) and total phenols were significantly affected by ozone concentration and treatment time. The results presented demonstrate that a desired 5 log reduction can be achieved within 5 min