Effect of ozone treatment on quality of orange juice

Orange juice and orange juice fractions were treated with ozone to determine the effect that ozone has on ascorbic acid, color and Saccharomyces cerevisiae (predominant spoilage yeast in orange juice). Several foodborne disease outbreaks associated with fruit juices over the past decade have brought about new regulations by FDA requiring juice processors to implement a Hazard Analysis and Critical Control Point (HACCP) program and a 5-log reduction of pertinent pathogenic organisms. Those unable or unwilling must provide a warning statement on the product package stating the possible hazards associated with consumption of the product. High-temperature short-time (HTST) pasteurization is predominately used in milk and fruit juice processing. However, the high cost associated with this method has led to research on less expensive methods to achieve a 5-log reduction of pertinent pathogenic organisms. Ozone is a possible alternative to HTST pasteurization. Ozone has long been used in treatment of water supplies and as a sanitizer. Recently, ozone treatment has been shown to be an effective method in achieving a 5-log reduction of Escherichia coli O157:H7 in apple cider and Salmonella in orange juice.; Analysis of ascorbic acid in orange juice and water + 25mg ascorbic acid/100ml revealed that ascorbic acid was almost fully degraded after 90 min of ozone treatment. Spectrophotometer readings showed a significant (P < 0.05) decrease in redness (“a” color value) in ozone-treated orange juice, although, the difference was not visibly noticeable. In preliminary studies, ozone treatments longer than 150 min led to visible color differences (i.e., lightening). Seven different samples containing various components found in orange juice were inoculated with S. cerevisiae. Samples lacking or containing very low levels of ascorbic acid showed a significant decrease in yeast populations, with yeast being undetectable within 5 to 60 minutes of ozone treatment. Samples containing ≥6mg ascorbic acid/100ml solution had no significant (P > 0.05) effect on inactivation of S. cerevisiae. Survival of S. cerevisiae was not significantly different between ozone- and air-treated orange juice samples after a 5-day storage period at 10°C. An accelerated shelf-life study was terminated after yeast counts increased to >5.7 log cfu/ml.; Although ozone treatment has been proven to reduce pathogens in fruit juices, ozone is not recommended as an alternative to pasteurization of orange juice because ozone reduces ascorbic acid levels and alters typical orange juice color. Furthermore, ozone was ineffective at decreasing the level of spoilage yeast in orange juice.