Effect of ozonated water on the microbiological physical and nutritional quality parameters of minimally processed lettuce during shelf-life

Summary

Since chlorine is not accepted for treatment of organic products, alternative sanitizing agents are needed to assure the safety and shelf-life of fresh-cut organic vegetables. Therefore, the effect of ozone on the microbiological, nutritional ands sensory quality of lettuce were studied during shelf-life at 4ºC in this project. Ozone gas was produced from extra dry oxygen by means of a corona discharge generator. After spinning, samples were packaged using 35 μm oriented PP bags and stored at 4ºC for 13 days. Sampling was done on days 0, 3, 8, 10, and 13. Analyses include aerobic plate count and psychrotrophic bacteria, vitamin C and sensory quality. One chlorine (100 ppm, 2 min) and one organic acid (0.25% citric acid plus 0.50% ascorbic acid, 2 min) disinfected sample were used as control samples during the shelf-life study, as chlorine is the generally used disinfecting agent in conventional processing and organic acids are one of the few alternatives that can be used for organic products. No significant difference was detected between the microbial quality of ozone, chlorine and organic acid disinfected lettuce samples. Although the vitamin C loss in 3 ppm ozone treated samples were significantly higher than the other samples, no significant difference was observed between chlorine washed and 1 ppm ozone treated samples. At the end of 10 days of storage, at a level of 5 %, no significant difference was observed between chlorine washed and the samples treated with 1 ppm ozone for 2 min.