Comparison of Aqueous Ozone and Chlorine as Sanitizers in the Food Processing Industry: Impact on Fresh Agricultural Produce Quality

Abstract

The effects of ozone treatment on fresh strawberry and shredded lettuce food quality were tested by varying applied ozone concentration, contact time, pH and temperature to assess ozone a potential food sanitizer. The produce quality was assessed by comparing the changes in texture firmness, browning and decolorization, oxygen consumption and carbon dioxide respiration after the post-treatment storage from 0 to 21 days. The effectiveness of ozonation on natural microfloras including mesophiles, psychotrophes, yeasts and molds, was also evaluated for the improvement in produce shelf-life. As compared to chlorine treatments, ozone treatments slightly increased the lettuce browning but substantially retarded its respiration rates and firmness deterioration even after 21 days of storage. For strawberry, no significant difference in food quality was observed between ozone and chlorine treatments. Finally, ozone treatments at the doses below 10 mg/L were found not effective in killing natural microfloras grown on the produce surfaces.

Keywords:

• Ozone
• Disinfection
• Food Quality
• Natural Microfloras
• Ozonation
• Water Treatment

ACKNOWLEDGMENTS

The authors would sincerely acknowledge the financial supports from Ontario Ministry of Agriculture and Food through the Food Safety Research Program, and from National Sciences and Engineering Research Council of Canada. The contributions from Pride Pak Canada Ltd. to provide the test samples and the permission to access the laboratories at Food Research Program, Agriculture and Agri-Food Canada at Guelph, are greatly appreciated. We are also grateful to Dr. R.C. McKellar, Dr. X. Li and Ms. C. Defelice from Agriculture and Agri-Food Canada Food Research Program and J. Rykes from School of Engineering, University of Guelph for their advice and assistance in collecting experimental data.